Pretty exciting for Science in my decision there for science or for science to your six six four years. Thanks for the introduction and very nice back and giving a talk here and the work I talked about today is actually a very new work that we're just getting some results for now I'll try to sketch out a lot of the details and it's all work done by dodging the student who is a graduate student in my group and just picked up this project a couple years ago after working on a different one for a little while and she is that an exceptional job thinking about how it is that we can influence materials processing by virtue of thinking about the self-assembly of biological molecules everything we do really thinks about how it is that we can use rational design to generate protections where we can manipulate sequence and control secondary structure and self-assembly what we wind up doing that is taking these molecules and this is an example of one of those small. And see if we can't control the pathways for self-assembly and combine them with the pathways nucleation and growth to see if we can't then generate complicated structures structures with more than one length scale and actually what I mean by that in a minute from a natural example but first I just want to briefly say this is a molecule that's the peptide molecule it has seventeen amino acids. It has an alternating periodicity meaning that it has I differ because you know acid by hydrophilic them you know acid bad phobic meter acid hydrophobic when the shown in yellow to fill in the shade of blue and you can see that that generates an empathetic molecule with trip to fan sitting at the end. So you look at the molecule and it's going into the you wind up generating a molecule with hydrogen bonding in the plane of the page hydrophobic down going how to fill it and it's just a toy we can play with this molecule we can understand how it self assembles and we really really like the fact that it's a very simple linear molecule and we'll talk about how we can define chemical functionality along the backbone of that molecule to really think about materials design. So before I start talking about the particular design. We tend to try to define ourselves in a given field in the field that my group has thought about is really matter molecular materials and there's lots of ways to think about math homework in materials the way we like thinking about it. Putting ourselves at the very top of this latter is in the following axes moving down you have an increased diversity of chemical functionality to the very bottom of this list you have random polymers you have things like polyethylene polystyrene lots and lots of control over very high molecular weights but you lose control of attack to city you lose control of the ability to really control Pods Firstly precisely as you start to move up this axis you have an increased capacity for folding in self-assembly so you can pursue more precisely control handedness of these molecules you can more precisely control the molecular weight you get mana dispersed polymers from things like and cattle. You get structural block of polymers and then you can start playing with diagrams and getting in the face face that. Things like double gyro and hexagonal patterns and really then as you start moving even farther up you can start to see protein based polymers which can be very very precise structures as you get to the very top of this and a lot of people here start have started working on this you get natural engineer proteins as well. Sequence specific ligaments and this is really what I'm going to talk about things kind of a philosophical question that I've included in the corner here. Do these arrows really have to move in opposite directions and there's really marvelous work that's being done all over including here on non-natural meter last has been incorporated into the sequences that allow you to have very very diverse chemical species that also have interesting structures and abilities to self assemble. So what are we talking about is our goal to try to design molecules at the top of this list where we can really control an official assembly and then by virtue of that control nucleation and growth processes in complex systems we have like I said more than one length scale. Let me started with was really self-assembly and I want to find self-assembly for the study and what I'll do is highlight a couple different words the first a spontaneous we want to try to drive the formation of structure spontaneously to frantically of assembly to be negative. We want to be able to have stuff assembled structures that are non covalent for Palla processing of complex neither also super molecular and so we just design the molecule with the information required to solve assemble with in the sequence itself. I want to talk about three dimensional structures there's a large effort my group actually to do dynamic surface activity by virtue of controlling the unfolded state and then controlling the fact that state where the forward state is in fear like in self assembles the end folded state is not really think about this is a simple first sort of reaction although it's much more complicated than that and then we can actually have tenable. Structures talk about exclusively today really thinks about this to the self-assembly and make molecules that have this architecture like a shed which hydrophilic on one side to focus on one on the other side and the dynamics to make non equilibrium materials really lie. Yes And the fact that you can control new creation and growth rates but you can also control diffusion self-assembly rates and so a wonderful example that I've actually rotate the examples I get bored with certain examples but this particular example actually comes from a broad war and the bread warm and it's not shown very well here is the bedroom itself a show here but a tooth is not. And so it has a tooth of the very tip of its head and that tooth actually serves two functions and what's interesting about that tooth is the first function and its second function are actually contradictory to one another. The first function is it needs a very very high lastic modulus to penetrate the shell of mollusc for instance and that's what it eats for food but it also needs to be able to hide itself and do it. Inside the cell and so it needs to be abrasion resistant right and abrasion resistance is contradictory to that it has the Youngs modulus in the in the denominator. And so the higher the stiffness the lower the greater resistance is a trouble logical property where you want to actually have a very high hardness and so from Imperial standpoint how do you do this. How do you actually solve this paradox. We have something where you want a very very high hardness but a stiffness that's also hide but you know not so high that it a bit reduces your brain resistance and and the answers microstructure the answers to template minerals and such a way that you have lots and lots of small crystals. Now one big crystal rather lots and lots of fiber or small. Crystals and it does this very effectively to get both high stiffness and high hardness at very low mineral contents and so it actually mimics in this case a lot of properties that are in your teeth and your teeth actually are something like ninety percent mineral and so you know it does this with much much lower in again a content and so it's a wonderful example of how it is that by virtue of controlling structure. You can control the tears properties but you can control them in a way that. Rinds requiring complexity of structure right and so this is really our aim. I mean how do we get here. How do we get to something where we have a template molecule but that template molecule controls the Christopher mation but doesn't control the crystal structure and the answer is in my opinion. What has become the field of head or tactile growth and the series existed for a number of years. It's it's certainly older than a couple of decades where the predominant thinking over the last fifty years has been has been shown to be somewhat incorrect the predominant thinking was you have a sort of manic template and I'm showing that they're what interface because for them it experiments that are going to strive to predominate think is you have a certain a template and on top of that sort of get a template you started to recreate the inner getting. So this organic templates very well defined if you start to by virtue of the coordination on to the organic pattern and energetic structure Well this actually isn't the way to make complicated structure how you want to make complicated structures actually this more Securitas route where you start with deposition on to that interface you get depth densification as you start to weight as a function of time and then you get face transformation into these structures and by virtue of this you can actually have a much longer pathway and multiple energy steps and so thermodynamically it looks something more like this for the direct epitaphs field pathway as far as the free energy is concerned it's one big step but the pathway towards getting these more complicated structures is more steps. So for instance in this first step you have a more fair steppers mission to form a very small crystals followed by kinetic steps that are governed by self-assembly rather than just new growth and so we think that this is key and we think of the system that I'll talk about next is really how you get there so far as a nice fundamental approach to understanding these complicated structures that wind of forming on be organic template that I'll talk about. For the rest of the top is this particular type of it or a should start by virtue of it thinking about rational design with think about how it is that we can design a sequence and pattern that organic interface in such a way that not only can we have chemical functionality presented with a very precise centimeter length scale we can also assemble this in two dimensions after we sever the can we really understand the phase behavior to really understand both the inner molecular interactions and the formation of larger higher order to self assemble phases to form these patterns and then by virtue of that can we actually control crystallization phases of the organic I'll take you through at least one iteration of this script a couple of the bad things that we did along the way that were in quick steps. Except to say to the graduate students that it certainly wasn't up aeration and so again I'll step by talking about design so can we actually design a surface active second structure of this alternating period. Can we define something that sits at the air water interface and is stable there. Next we'll talk about can we actually control the self-assembly in two dimensions and really what we wind up seeing over and over is the transformation from these mysel or stages into these superstructure I'll show you what I mean by that using string on my cross to people next step is can we really understand the inner molecular interactions on the surface forces by looking at that phase behavior the transformation from a gas phase a century to condense phase to the Cybill or phase and then last we actually control nucleation and growth process is very much like the blood worm does and it's to not only do you have a crystal phase but you have a crystal phase that's where our line and small fiber organizations and we're really starting to get towards that. Now as far as design is concerned I don't I don't want to have him with details about the hierarchy of structure of proteins I showed a slide not as a tutorial rather to really try to emphasize what it is that we do and what it is that we think about when we're doing design. So this. Pad that we design is usually very small typically between fifteen and thirty amino acids it typically has a molecular weight of rest and ten thousand from all the primary structures just the sequence that we write down how this hypothesis would put the pellets on paper. You know where it is that we think we need to design as far as controlling the second a structure and controlling them for Felicity in a molecule such shown one example of the primate structures and Alan ina life seen Lucy and Alan in a coup attempt at that and I salute scene and another two to make acid which particular septet this particular sequence of seven amino acid does nothing at all by itself it does nothing when you start repeating it though over and over when you have three four five repeats of the seven amino acid sequence. It starts to form secondary structure in fact it sets to form an alpha helix way in trauma like you are hydrogen bonding starts to form this alpha helix. And you actually by virtue of the periodic structure lined up with hydrophobic base and hydrophilic face very much like the molecules I'll be talking about for the rest of this time I include tertiary structure the three dimensional structure to say that we don't touch this were not intrepid enough to try to design tertiary structure this mixture of things like sheets and heal a season hydrophobic interactions becomes far too complicated to try to understand Aspies understanding and moving forward with fundamentals of materials but I think we skip this we go straight to what I'll call quaternary structure but it's just self-assembly those are the non covalent assemblies of proteins is a classic illustration of hemoglobin where you have proteins separate sampling to form a structure but all based on non-privileged interactions. So we take this idea designing this hierarchy of structure and we really start with kind of a list what do we want the molecule to do what is it that it needs to do what are the design criteria for what we're trying to do and the first and second are very clear we want to stable and facilitate that architecture. Something that exhibit hydrophobic base exhibit hydrophilic face and sit at their water interface a typically these molecules have to be insoluble in water to sit stable at the interface just very different from typical protein molecules The second thing is we want not only for babies she preference but we want hydrogen bonding to dominate in a molecular forces that means instead of just having something like electrostatics with a positive a negative molecules kind of interacting one hydrogen bonding in the plane of the interact interface to dominate those interactions. So that by floating these guys at the interface with the hydrophobic in or through the hydrophobic amino acids twenty up to thirty communal aspirin down in the plane of the interface all the C.E.O. groups and all the age groups wind up interacting with one another with very strong hydrogen bonding interactions This allows us to suffer some of these molecules as a function of pressure and so the question still remains can we design a molecule to do this and what a kind of sticks that we'd like to use to be able to publish SOP And the answer is we really just use two very simple rules of thumb the first rule of thumb is one that I'll call it and there's also a new one. The old rule of thumb comes from a classic paper one hundred seventy eight and turns out this list hasn't changed very much. Since then published by showing fast men and it specifies an intrinsic propensity for certain amino acids to be in certain secondary structure seven you know acids want to be an alpha he was some of you know acids want to be in beta sheets. You know I says I want to be an alpha healer scenes are shown here the last thing they want to be in data sheets are shown here. And so if you want an alpha helix for instance you just choose a clue to make acid A Alan you know Lucy in his fifty and these were ten when repeated to form an alpha helix in order for these data sheets that we want. We've had to have a lean which direction is France that's the second. It's a it's a newer provides for those characteristics at the same time it provides fair Felicity ended the fines said Peter. The that it's the formation of secondary structure. So for instance an alpha helix has appeared a city of seven amino acids for every two turns to choose amino acid number one number four. Number five and number eight of the same. I just for busy tend to define a hydrophobic face that hydrophobic face will tend to want to self assemble and then form an alpha helix. Alternatively because of the CHI reality of a beta she ever needed acid in a beta sheet. If you choose an alternating period a city so every two amino acids. I just had to feel like I just had to fill it had to fold it had a feeling you had to form all those hydrophobic interactions on one face of the peptide of the hydrophilic amino acids wind up being on the other face and so if you choose amino acids that are at the top of this list of chemical or shit like propensity and that have this alternate to decide that you really can really drive the formation of a beta sheet that's F.L. I can see lines of capitalizing on that sequence and the ability to form self-assembly by virtue of empathy Felicity Now this is kind of a lesson that I use for all my newer graduate students now this is our first generation molecule it's completely functional it worked exactly how we wanted it to but it made no sense at all. And I'll tell you why. So we designed the sequence. I think it was something like twenty eight amino acids long. So this is one leg this is another leg we designed a hairpin very nicely. So it's the best meds actually wound up being straight in the plane of their water interface. It's charge all the negative charges on one face all the positive charge on the other face so that in a molecular interactions tended to want to stabilize the type alpha helix or a tight hairpin and has here which is assisting group a group here which in those distinct. So when they align by virtue of these charges with other molecules that are similar. We can cross-link them and form a stable interface that has these two groups one is a trip to fan of the others higher scene so we can characterize the. Tracing in two dimensions and figure out how much we actually have of the interface and then we put it at the end if a self assemble it it does exactly what So this is actually an image looking into the sheet from this side right here looking down this happened legen this hairpin leg and you see all the hydrophobic groups here and all the hydrophilic groups here and that's what we wanted it to do nicely as long as it faded nicely and it worked very well the problem is it was way too complicated but if you're trying to make a fundamental study about materials design and how it is that you can process things with a pathway coupling Nonny for Librium self-assembly with Dani probably nucleation to this is the wrong molecule to use and look at on paper it made sense when we synthesize that we worked with it for about two months and then we said well that's the next experiment and my state and I looked at each other and perhaps I should know better but she said I don't know and I said I don't know. And so we had to throw this move this molecule away and it couldn't teach us anything about the fundamentals of the process because it's too complicated had too many charges here too many charges here too much complexity here happened where we didn't necessarily know although in theory it should have right fried it could have tilted a bit back and forth and so I tossed it. We tossed it much simpler molecules called these the second generation molecules and what they are I'll call them Beta nine and Beta three and I'll tell you why in a second. It's seventeen amino acid sequences where the charge groups are separated by two different likes right. So this has the same alternating create a city its failings on this face and then to charge groups are spared despotic acids on this side and this side right this one is separate from this one by nine amino acids so one two three four five six seven eight nine. But this one separated by bit from from this one by three mean I says one two three. That's Beta three and bit and nine when allowed us to do is have two molecules that sit on their water interface where the charge repair shed is based on just charge separation pro molecule but the overall charge for molecules the same sequence of this Mollica. In this molecule exactly the same in terms of the components of amino acids. All that is different is the spacing in the you know acids. I have a down here to kind of show the difference in the spacing between those two molecules. So now we have a molecule that how's this ability to sit there. What interface to suffer somebody by virtue of hydrogen bonding in the plane of the interface and we can really precisely understand what's going on with the ice affirms by virtue of the fact that we know exactly the difference between this molecule in this molecule. So here we have to make the molecule now there's a variety of ways to make these sorts of molecules we use a technique that is solid face peptides and. We do a lot of chemistry we make these molecules ourselves in the lab and what you wind up doing with solid face peptide chemistry is very very elegant it's it's elegant in fact that Bruce Mayfield won the Nobel Prize in Nineteen Eighty-Four by virtue of the fact that he had a system maybe one of these molecules and he made Robyn to please a one hundred twenty four. I mean acids and it fell of the just like privately creates a I don't think he made enough to check its activity but he certainly was able then to say that you can sympathetically make a whole protein we want to do nothing as complicated as this everything we want to do is to make very very small sequences the sequence that I showed is the seventeen amino acids and so we do and I don't I won't spend too much time on it as we start by attaching one amino acid to a solid case polymer So this is a big rock that's about a micron in size right. We take this polymer and we attach amino acid number one and then you have the Palmer with amino acid number one and this protecting group which is known as an ethnic group we cut the F. block group off in a process that's called the protection and then we have a free Amine that's ready to react to take amino acid number two shown here with an activating group and it couples to that three I mean. And then it winds up form a amino acid one an amino acid to protect it with an ethnic group the protection group actually takes only one of these. At the time and not a whole bunch after how did this then you just repeat until you wind up with the seventeen sequences or seventeen amino acids and sequence that you want and then you clear that off the polymer and then you have this free peptide with seventeen M eight amino acids that you clarify using H.P.L.C. mass spec to verify what you have to this whole process you actually automate you don't do this by hand anymore the arrogance of it is that you just start it up overnight you don't have to do any purification during the reaction because it's on a solid face so you don't have to do any recourse lies ation you just filter out the polymer with within you know assets that are growing and then you cleave it and then you do your purification at the very end. We usually get a year now not initially around ninety percent we purify that around ninety eight percent. So this is just a picture of the robot and you can see we program in the sequence in these vials it's very very easy. You know if you have amino acid in one two three four five six seven eight I ten just rotates and does the reaction one at a time in one of these three reaction vessels and then the wind up with a polymer with a bunch of peptide around it that has the exact sequence that you've programmed here. It's a very very easy process the end you can actually look to see if you can see this from the back the purity of these molecules right so this is a scale See this is the product peak and this is the mass back in the mass spec shows that we get the molecular weight more or less precisely that we want. They designed the sequence and we've designed the sequence to have this alternating period a city where all the hydrophobic groups are here all the hydrophilic groups are there. Can we actually control the phase behavior by virtue of putting these molecules on an interface we can travel lateral diffusion coefficients of the self-assembly as we start to increase the concentration allow these molecules interact with one another in two dimensions as they can find on the interface. Here is how we try to do that we take. This instrument which is known as a language logic trough. I like to tell undergraduates because they see this you know as this very new tool but it's just like a piston cylinder It's just like a piston cylinder you put ammonia at it you start to compress to see a face change the function of pressure as molecule start to interact with one another higher higher pressures you get a face change rate and sell this is exactly what's going on except into that you feel this trough up with water you put the molecules in two dimensions you close the barriers which is exactly the equivalent of compressing the piston and then you start to see self-assembly or face transformation in two dimensions right on that air water interface right when you do that the molecules theoretically to align it and then we'll see if we can't actually control how it is but self-assembly occurs in two dimensions and when I say is there's three things I'll show next and these three things to which unexpected one of which we kind of knew was going to happen. So the first thing that occurred. That was somewhat unexpected is there's the first order face transition surround showing here is what's known as a pressure area I saw thermos just the same as a P.V. diagram except into the units match instead of having per meter squared. It's millions per meter and there is in terms of banks from squared plate and so what you see is that you start to decrease there you start to increase the pressure but if you have classic phase transformation if you have a classic face pitch mission as you increase the pressure you get to see a plateau and then you see it increase as it goes through would face for instance we see a transformation from the gas phase to the solid phase but there is no first order phase transition that we expected a little bit more about why that is absent in a second. I'll tell you the two other things we observe right out of the gates first the next thing we observed is something that was somewhat unexpected to three smaller than beta nights and let me remind you again Beta three was that molecule where the charges were closer together nine where the pads those charges were a little bit farther apart and so we expected the molecules that had the. Are just slightly more lies self-assembly more readily that actually doesn't happen. Beta nine is shown here in red in the Beta three shown here. Run hypothesis and we're actually verifying that now with some reflectivity tools is that the beta three by virtue of the fact that it can pack those charges a little bit more tightly and it doesn't necessarily need to self assemble and then allows you to actually get to a better packing in two dimensions by staggering its assembly in in a way that shown in this cartoon here. This is true then lots of other sequences where we play with the position of the charge at the charges or closer together as long as there's two charges itself assembles better. So the last thing we observe this is kind of the thing we expected to observe is that as you start to compress compress compress change fades self assemble allow hydrogen bomb to do occur as you get to the highest possible pressure and you decompress. You always see history sis and we can do this over and over and over and we always see this history says where the assembled state then fall straight down as far as pressure to disassemble state after each kid. Only then can he actually bring it back up and hypothesis here is very palm Merican nature so if you were to take the high molecular weight polymer in the melt phase and put in a tube and started flowing it. It would require a critical velocity and that too. Before it had a snap straight right. Then you could start slowing it down as you said to reduce the velocity. It will stay straight to see a very strong history since the flare was a function of pressure until you reached another critical philosophy and then back up to believe this is what's happening here we have a little bit of evidence for this and it's increasing pressure it doesn't actually interact with another molecule until it reaches a critical pressure the hydrogen bonding then takes over and then after it snaps street then it's the need to start dropping the pressure back down and a wind up falling down and the December state is persisting. As he decreased the pressure and we actually have some evidence for that. I'll show in a second as well. Can we verify that what we think is happening is happening as far as the molecular structure in two dimensions and I'll tell you what we did to do this we did we did we did two spectroscopy techniques we have F.T.L. we have such a look at the secondary structures the function of surface pressure at the molecules directly on the interface instead or we do as we transfer these molecules on the courts to sort of functional eyes with their Ts and such a way that we have a model of these molecules presumably preserved in their state on a solid substrate and there's a lot of artifacts that can occur when you do this sort of thing we actually take something off their water interface and put it in a solid substrate there's a lot of things that can happen that make it so that you can question whether or not we're looking at the right thing. One piece of evidence that suggests that we're looking at the right thing is that the transfer ratio is always one and so what that means is every time we take this what's just been pushing through their water and face to the positives molecules on that it want to face. We see a decrease in the area of the surface that matches the area of the surface associated with that quartz disk. So everything. Presumably that was sitting on the interface is now on that point. Sis We take that puts this and then we do things like circular diapers and spectroscopy secondary structure as a function of wavelength. So what you're doing in Circular Diagram spectroscopy is you looking at a higher kewl. Structure if you have a color molecule periodic structure and you look at the difference between the raft on the right circular polarized light and a characteristic spectra So we're shown what I'm showing here is several characteristic spectra So this is the main residue with this it is a function of it. Wave like the only thing you need to remember about this chart is what this is doing is pointing at a particular wavelength around two hundred fourteen nanometers at two hundred fourteen nanometers a beta sheet has a minute mine. So if you enter data sheets structure and having them for instance if you have an alpha helix you look at two hundred twenty two and around two hundred eighty. See to minimum. This is a data sheet if you have this minimum size that you have a beta sheet and sell we look at what happens is a function of service pressure. What you'll see is the following the red triangle comes from these lower surface pressures these higher areas and the red circles. That says my time machine hasn't backed up for twenty days. I'm surprised at that shut down my presentation. There we go. So the green circles to the green circle show that we have is it a sheet structure at fifty million units per meter much higher pressures right. And so going back to this you're looking at a look to see it as a function of wave like at these low pressures this is where molecules to float around freely at the interface where you have is very little second ish action that might actually be slightly out here I don't understand why that is as you start to increase the pressure what you see is this minimal developer two hundred fourteen nanometer as minimal as indicative of secondary structure at the interface and this makes sense configuration only the entropy is going to dominate at these lower pressures and prevent you from reaching these very well defined secondary structures even there. That's what they have a history of the molecule wants to do so this is actually backed up as well by using a technique called attenuated total reflectance F.D.R. So it's just like the F.D.A. experiments that you learn in under bad except for we put these things on interface and we look at them with attenuated to reflect this. But this means you take iron through that prism bounces the source back and forth and by the fact that way right at the interface where you can do it you can look at what's going on very very near the interface so the signal actually to Kazan it as an exponential away from the. Interface and so when you have these puppet sitting at the interface. You can actually try to amplify by virtue of the bouncing the signal peptides as they sit close to the interface plate and then you can look at the wavelength and then see where the wave numbers I suppose. And you can see whether you get random coil a week but a sheet or an intimate life strong data sheets and this is a strongly forming hydrogen bomb and that what they're there for to soak the rich it all showed red and the strong sheet all showing green. On the following side and it's shown here. And so this is at three different pressures this is shown at five millions per meter so at the a large areas at twenty five million Indians for meters you start to compress at fifty million from either way you have this very very small area per molecule right. And let's start by looking at the week sheets of the week signal actually at five millimeters per meter is fairly small and if you search it compress it you actually get slightly more we keep saying no and then as you compress even farther. So this is at twenty five and you can press even farther you wind up getting something in between the two which is really confound NG until you look at what happens in terms of the F.D.R. signal and the strong on the strong so you see very very little signal as far as five million inspire me to it increases the sexy twenty five million. And then increases even further was you get to fifty million from it and this really supports this notion. This is such a crowd the molecules in two dimensions will start to form this beta sheet of the plane of the air water interface and so the question remains what happens as far as these molecules are concerned. I mean we you can kind of envision what's happening with these molecules. But we've enlisted the help of and I want to talk about this is actually very recent We listen to the help of a couple of the attentions to do simulations as far as what's going on at high areas that medium areas that have a very small areas of molecules and you tend to see a couple new things that we didn't expect the first is well of course you wind up with the staggering enjoyments which was borne out in the L.B. experiments but you also wind up with and I've only shown want to four here and wind up with a lot. These tea like structures in immediate pressures you tend to form assemblies that aren't necessarily dominated by hydrogen bonding actually and that we spend a lot more time exploring but instead talk about these equations of state and really how it is that we can quantify their molecular actions as a function of surface pressure and to do this some way of visualizing the change in phase the function of service pressure and some of this restraint in my cost of P. and research by end of my cost is a really really nice noninvasive technique to look at and what interface. So what it involves is bringing in a laser beam at the boost angle and at this. Bruce triangle. Essentially what happens is if you use polarized light the surface disappears. If there's nothing on it every time you have something of the different refractive index on that interface. You can image it by virtue of a jet is sitting on the reflected side of that laser beam and so this is just a sample of a faster lip of that stuff assembling in two dimensions. Right. And it's a very very nice tool to see face change without including any for us and dyes and so this is what happens with our molecules as you start to compress as a function of area and you wind up seeing a change in the phase behavior that's very very distinct so I'll describe to first say what I want to say about how robust this phenomena is so as you start to compress from there marrow surface pressures five to thirty five to forty or fifty and fifty two. You see a transition in the structure and we only see the same transistor in structure as long as you have a periodic sequence. It doesn't matter whether it's compressed in like on Beta. Beta three or out is in Beta nine we see this transition from my cellar phase at these very low pressures to these islands that kind of intermediate pressures and these fibers at very very high pressures to align. Fibro is a very very very high pressures and so this transition from the gas phase to condense phase to a solid five phase is consistent and this is actually what we kind of expected. I should say as far as the history says consider as you start pulling back down and pressure. You keep this phase until you get the very very low pressures and a house back you can really understand what's going on as far as two dimensional self-assembly by virtue of an equation of state and I'll talk about efforts to do so I think we've actually made a pretty significant effort to do this properly. You can think that much like I said earlier about the pressure much I can think about the pressure of volume diagram for something like an ideal gas it's P.V. is equal bad R.T. when you talk about three dimensions it's pies equal to Katie or egg. When you think about two dimensions and you wind up with something that looks like this there's no phase transformation there because there's no term that takes into account intermolecular potentials. If you want to take into account in a molecular potentials creation goes through what's known as the equation which is very much like a Vanda Walser variable Quezon of state except in two dimensions right now pressure is a function of that thermal energy area. The molecular area and cohesion pressure right. And so very much like in three D. If you use this equation a state where you see a face transit from a should occur as a function of very decrease Sherry increase your pressure and you see a face transformation in this region right. So this doesn't account for self-assembly though. This doesn't account for the what happens when these molecules transition from a state that looks like this is right out and simulations a lot of these teas to state that looks like this where you wind up decreasing the area and saying alignment due to hydrogen bonding. Well in order to do this we actually I should say that my student I sat. Down and wrote down. You know what we found would be a nice equation to govern self-assembly for the better part of a month and then we went to the library and found that other people had had done so very nicely in the last ten years or so and so again the lesson of the graduate students is that you know a few days in the library might save you a month and it was fun to do with the student but famine and verify wound up doing was thinking about aggregation within this equation a state so they thought about not only the number of aggregates relative to the number of monomers which they seemed was a small number. During the transition from a disassembler say to December fifth. But they also thought about this aggregation number being very very big we assume that this is a correct assumption because we have lots of molecules that form very large aggregates as a function of surface pressure and when you do this you wind up in that equation a state that incorporates the same sort of molecular area to small molecular and also incorporates a critical area of a critical area is very much like the inverse of a critical myself concentration so this is the concentration a bad thing which is a fact of molecules said to form self assemblies and he takes the inverse of that you have a critical value and in this case you have a critical area which is just too critical and in two dimensions. When you do this you can actually fit the data very nicely and this is a fit for Beta three the red line is the fit the blue lines the data and you can wind up saying wow you know we have a molecular which matches how big we actually think the molecule is it's about one hundred sixty actually scared and you have a critical area above which which she wind up having self-assembly is right and so that's about one thousand one hundred X. from squared away and so this really gives us an idea about what's going on with these molecules as you start to compress and it allows us to explore what happens if we have different sequences. But it's so far shown you two sequences we made two more the two sequences I sure was a Beta nine and a beta three. We also synthesize the Beta three eight and after this is doing the only difference between the beta ages we've substituted those charged groups for his sitting groups I'll tell you why in a second the system in groups that are ph sensitive then no longer charge the positively charge only a particular ph is right and so we expected to happen is exactly what happened in the area. The smallest area this Omega term which was noted and not there becomes smaller right. The critical area also becomes smaller as a function of switching from these charged groups to these histidine groups and this is actually kind of the we expected as far as the assembly but now we have a way to really think about what's going on with these fibers is a function of the surface pressure valve and one other thing we thought about doing image analysis on these images and what the image analysis allows us to do is really isolate whether it's fibers are right. So this is an image that's been modified such that you can not only figure out the function of the view that's occupied by the fibers you can also figure out the with of each individual fiber and then figure out what the average with is within the screen and done that experiment and what it tells us is it tells us the types of intermolecular forces that are dominating here. And so our backyard McConnell spent some time thinking about the free energy associated with the formation of straight faces red and these are either straight faces that transition from myself or faces which is exactly what we're observing right. And so the straight faces are shown here the primitives are things like the with Mount of the field occupied a dipole density in a line tension right and so really what we want is these in a molecular action to really what we want is the ratio of the line tension to the dipole density plate we have all the other parameters we know the area that occupied. We know the stripe with we know the occupied overall area for these molecules we can really figure out what the line tension is now relative to the dipole and so. I should say but these dipoles point to the direction of the plane of the interface a bit odd repulsive very much like the molecules. Minus two charges or minus two charges close together expect repulsion into line tension etc to form these stripes right. And so we do this we actually can be very quantitative about what's going on the numbers bear out as you'd expect measurement of the line tension of a dipole suggest that Beta three is the big S. bit and nine is the next biggest Beta three is the next biggest and then Beta nine. Is this next milestone but a nine is a small Saval right and that makes sense because remember that a nine is for a charge but a three eight is not right and so this dipole time gets smaller and smaller as you go and this direction. Right. And so this image analysis combined with understanding the equation of state. I do this to then express my final hypothesis that our final hypothesis is follows. Can we actually take this idea when we design a molecule assemble an entity try to understand it a molecular actions and then control crystallization. And some Put another way. How does crystallization different if you're here says if you're here. How does crystallization differ if there's no self assembly because it's a simple sound. Which is here where you actually can drive self-assembly in this direction. Well what we did to do that experiment is we took it in this case and then we hit Cyber Lies in the subways. We looked at how self-assembly took place at low pressures and then we looked at how self-assembly took place at high pressures when you actually self-assembly low pressures and said This is the brute strength of microscope again and then this is the brute strength of microscope after coordinates with but you wind up forming via T.M. images is the formation of these large distinct Christhood structures right and you don't wind up with anything that looks like the blood where you don't wind up with microstructure you don't wind up with two like scales right over them on my scale that. Defined by new creation and growth only right where you wind up with if you have packed organic faces. This is the organic face fifty million units per metre so this is this image where they tend to be very very aligned into these by building structures. Again this is the blue stripe on microscope and it's the Bruce triangle microscope with the it's frustrating crystals forming and so if you look at the scattering patterns of these you see tons and tons of peaks associated with any given Crystal because it winds up being bad day. Crystal in nature and this is what we expect it. Expect it's in the crystal are pressure part Crystal and high pressure and then really what we want to do is the following want to go to intermediate pressures where it's just about the surface sample and you can combine the time scales of socialist self-assembly with the timescales associated with new creation and see if you can't form something that's kind of in between write something that matches the fiber direction associated with the natural self-assembly these molecules and this is actually very near my seat actually just said this to me. So you go. And so what we wound up seeing when you started going to thirty millions per meter where you actually have to see it immediately. So some structures nucleation self-assembly we think is nucleation self-assembly coupled together to form these that are at intermediate phases where you have for sure. Diffusion and growth governing the formation of these little triangles. But that assembly dominating the formation of these well fibers and it's a nice way at Room pressure and room temperature to be able to have better access to those properties which you could never access otherwise if you have an equilibrium structure you can't do this when you have a non equilibrium structure can really start to control crystallization in terms of two ranks scales one and then two and this obviously requires lots and lots of optimization. That's very very new technology. And you know these are our first six or seven designs and so we really think that in the near future. Anyway. That you know materials processing that involves two kind of timescales is really what you need to do in order to embed complexity into these energetic types of structures and I'm just about out of time and on this side acknowledged the funding sources which were Air Force and the N.S.F. and my students and there's two students who actually did almost all the work particularly Lorraine who's sitting right next to the microscope there and the others who is and I used last summer and he actually figured out very quickly how to look at the samples a bit of a nice job and get him on the next publication with the stuff. Most of the equipment at C.C.N.Y. is actually shared and then we actually work a lot with Alex Charles and all the Reli on the bridge trying the microscope and the F.B.I. are simulations were done by Joe complex and we're doing these go crystallization experiments in collaboration with that Hunter which is another county school somebody helps us with image analysis and when I first started at C.C.N.Y. Henry's a person he actually did by helping me set up all this stuff which I had for thanks to look here's the problem with that particular experiment. When you start going over pressures you inherently got a very very low concentrations. Right. I mean I'm actually surprised we get much of a signal at all. We're talking. If you look at just you know there's a question right. There's a thickness term in that it's an animator to it's a very very rare and to be honest I think that's just noise and we've got it. Maybe twenty times actually. You know decrease by every time you run for more experiments or you know for more experiments and we've run it twenty five fifty one hundred times like the same sample to try to reduce the noise and it always looks roughly the same but there's a lot of noise in the process of fifty million intermediate it's not an issue anymore with a clear peak and that happens every time and actually I think that was just one scan that we could out. But yeah it's hard to say I tend to think that when you have low pressures and you have these molecules in what is in essence the gas phase configuration entropy is going to dominate the wind up with less structure I don't think you'll get alpha here to see just because periodicity so different. Right. I mean a period of seven and two can't really very easily be Quince And it's a period a city of two and eight. Sure you know maybe have happened you know a season is just starting out and so that so that I did so because you know in a given turn wind up in a safe place but in even an odd situation like that. I don't think it happened. So yeah I do I do. And part of the reason I think that's true is because if I can find the particular image when you look at the images and this is something I didn't mention but I don't quite understand yet so I didn't mention it when you look at the images the same sorts of things happen every time with all types of molecules that I've described in the Star. You always wind up with the so they get you wanted one barrier is here. Another big there's here. The bottom of the trough which is fixes here the top of the top which is fixes here moves this way this bay moves this way and then you wind up looking at this in the nucleation in the south somebody always occurs off the bottom wall. No idea why when you start to compress the alignment of the fibers and I should. Say that when you look at something that's angled like this is actually straight up and down relative to Barry because it hits in a face at an angle. So everything kind of all the fibers when you go to high pressures are always aligned with the barriers so I tend to think maybe starting the nucleation of the South assembled structures at the last but I'm not sure why I mean they tend to be very hydrophobic so maybe that kind of lined up sideways along them right away. It might be but here's the thing about that. So my student was doing this experiment initially and she showed me data that looked almost exactly like the first time she did the experiment and I asked you know is this kinetics or is this him equilibrium thermodynamics No really what I understand that there might be an Emmy for this space and I want to understand a kinetics of the crystallization piece and so I said to get around the experiments he was like OK so she went over to her for hours and you know she saw the same thing and I was like well you know let's try to find it a little bit slower and so she ran it over night and she saw the same thing and I was like well why don't we try to run the experiments and she said we can't anymore saying that evaporate the interface and it's dropping and the only move so fast and so you know build something so that humidity doesn't affect things as big and then she put these dishes and she put these warm sponges in the soap dish is just mad at me I'm sure the whole time and time and then she did the experiment like three days and sadly exact same thing and she's like See I told you and I don't really think you can generate I do that and make an action that compress the barriers that I have and I think I did a bonding attraction. But that's not right. I think the first order phase transition occurs. I think the first order phase transition disappears. Because it actually exists from here to here. Meaning that transitions are self assemble phases. If you have a fixed aggregation number if you're transitioning from a mysel that has you know that it also jumps into self-assembly then about seventy six out of seventy six are packing molecules sort of face transition that's not what's happening here. I mean what's happening here is you start to form these requesters maybe some t's and then you actually incompressible and you start to form these aggregates that you know hundreds if not thousands of molecules and then they start to grow and because of that it rocks and there's some evidence of this that washes out all over first or face transfers I don't think it's because you know we imagine it not because the model. You know throws out the first order phase transition so I think it certainly exists but it doesn't exist in a discrete fashion. But it certainly does it in the right thing to do to really explore that first started to clean it over and over the interface and then try different sort of interface to see if we can build a trough out of say something like you know kind of mind and see if you know it is you know roughness or the type of surface or the contact angle with that interface so if that happens we get where that that's very difficult it's very very hard. To do the whole experiment on you know pre-made trough we've actually made a whole bunch of little troughs but they don't work nicely it just never has a lot of the straps that we're building now are made out of different polymers we use this razor cutter that actually can very precisely determine the geometry of cutting out this this well essentially and then we can actually control essential the rock this right at the interface but still not seen anything different. Although we tend to think that maybe it is something. Exactly. If you're suggesting. When you Creation shaded by virtue of just the fact that there's a ball there. We certainly try to be very intelligent about figuring out whether it's the loss of the Bear In any case so it's in the well called the box at the interface. It's mostly self-assembly and so definitely a puzzle that we're still kind of exploring. So it doesn't drive towards the end goal which is to try to engineer materials processes were not equilibrium behavior governs everything but you know it's certainly something that to make sure we clearly define before we move on to much better area over there where we definitely done that show the data but a lot of work to do on the. Sort of thing. I mean a few different ways to some extent exactly what you'd expect. So that dipole intensity is going to it's going to. It's messy and it's not plain that presentation but what you're looking at is a broader show in blue and that increasing salt concentrations monorail it's all construction you don't want to play with situations and this is what I mean exactly what you'd expect would happen as you start to do this you start to drop the charges by virtue of dropping the charge decrease density as a function of cell concentration to move this what we expected to happen was at super high so concentrations this kind of brown curve but just like our history to try to make it through some pretty nice work like that for ages of eight and nine. It just never happened and it had to some extent when you start to go to these high school concentrations bad things happen and it's hard to govern but yeah we can't actually screen completely the star charts and actions but then experiment where you can actually start to fit. What's going on in this direction using the equations state and the image analysis to really try to understand what's happening is a bunch of stuff and it's you know less relevant to understanding crystallization understanding just equilibrium behavior of these peptides at their face as much discreet.