3 Polymer Dynamic Models, Sedimentation, Electrophoresis

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3 Polymer Dynamic Models, Sedimentation, Electrophoresis
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30 (Lecture 2 missing)
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Lecture 3 - sketch of polymer dynamics models, results from sedimentation, how electrophoresis works. George Phillies lectures an advanced graduate course based on his book "Phenomenology of Polymer Solution Dynamics" (Cambridge, 2011).
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classes in polymer dynamic based on
George Phillies book phenomenology of polymer solution dynamics Cambridge University Press 2011
ends today this lecture E is lecture 3 bottles
of polymer dynamics electrophoresis I'm
professor abilities missus course 597 phenomenology of polymer solution that I just can't do the 1st homework assignment is could pass to on doing the recording start property and we don't want that but 2 terms broke on the whole world objectives I have a citing the specific juror I have signed 2 years of the journal and horrifying interesting papers that deal with things that are similar to what you find in Chapter 3 I'm a homework assignment which goes on for page lists a whole lot different ways you can do searches by emphasized whether science because it's a citation who you need a whether science means that if you found good paper you can look at everyone who use that paper is a footnote in the papers that published that and it lets you trace forward and time exactly the same way as looking up footnotes lets you traced backward there are a bunch of alternatives for example if you go over the Journal and discover the issues and pieces within the issue the nicely sorted by the editors and since they are nicely started instead of just trying to read 2
years journal you can look Journal titles and the abstracts and you find a few issues that have most of the rest of the year you were looking for work the results you want I brute-force search works very well my book in substantial part is based on brute force search I actually went through most of the standard of journals going back over 30 years pulling out of however Chapter 3 is a little different chapter 3 uses of electrophoresis to study how Paul movement solution are you cannot find any other review on polymer dynamics because no 1 else realize the approach was possible I found it slightly by accident because 1 of the papers we discussed in in detail injected 3 it's work by a lot of our problem happens to foot no longer online the troops and the entire contact between polymer dynamics literature's most of you know you don't cost and this chapter was very tiny it was just 1 paper and 1 footnote cross-linked but I will tell everyone who had used by the papers a footnote and there was this 1 peculiar footnote in a journal I was familiar with the verdict journals and so we were able to do that what you're being asked to do is to take all these research tools and I missed a bunch of on homework applied only to 1 journals for 2 years but it's thick journals we've got a fair amount of paper there much more than you would want to read on your own but even if you just have to sit there and Poland the computer screen on Beijing time which news on the Internet after all the library bullet that should know how to use that for your gradual work but it this is a learning experience on how to library the target date is about 2 weeks out but next week we will discuss how much progress you have made and of making reasonable amount progress and we can adjust the target date if there are issues were challenges were got on the Internet use them for doing so I'm going to be somewhat flexible the objective is the end the right research paper of song reasonable number of pages and you will tell me what happened I realize a number of European and English is your native language as I told my other classes least a few students and I could tell English was not your native language because you did not make all of the sloppy grammatical errors the Americans state sir your written in English will be fine don't worry about it and I was a kid that's on your English but I'm not going to penalize you for making me aware rigor talk about all OK what I am going to do so the camera doesn't die again I assume still reporting on what I am going to do is to go back to what they were about what we said last time on Chapter 2 I'm sort fumigation I'm going do he somewhat different words what I said about Paul Merson's solutions I am going to to do however call your attention to couple sources you might find useful they and the 1st is to move into the the articles the bonds in the dancers chemical physics on the 1 used by Jefferies and once him the footnote in the full someplace they're both very good review papers if you read the 1st of all we'll get some background fearing more than you need to know their 2nd if you read the discovered people are looking at sort of the same literature not completely the current opposite conclusions shortly said ,comma different and finally particularly the large paper which is concerned with experiment you will get a fraction of what the review literature prior Michael and Lowell so there's some alternative places you can do some reading so let us go back and start at the beginning and his hallmark holiday solution it's very strong about its stringy but if you actually hear a pall over oil solution it tends to be a little more than half the time drama however over short distances and dryness and most of all possible worlds although over short distances you have a shot structure faced by covalent bond lengths and bonding bills over long distances almost all is not quite free rotate around that Parliament but it's pretty close and as a result over long distances a formal role in typical tends to resemble piece of Yoram along these garments dropped off work it's sloppy it's not flopping over short distances over short distances molecule that the fairly rigid the polymer molecules are very long and stringy and are fairly floppy soft white over boiled movements Saturday if I can hear the supply of oil and if I get you another of what we were in solution also sold all even then asked the question and is the thermodynamics questions you polymer coils prefer sit next to each other 49 prefers sit next to solve molecules if called Wells prefer somewhat sit next to each other that states of this floppy shapes that are fairly compare tend to be over if the power oil would prefer to sit next to other solvent molecules but polymer spreads out In extreme cases of this form is given us by protein now proteins are water soluble because the outside edges are coated with charges and with tighter filets groups things like compare to water but most of most protein molecules are organic things like methylene groups that artery water water-soluble and what happens is that protein molecules form balls off because water is not all consultant for proteins and because the protein molecule .period and forms always the same structure we have and sometimes use the actual basis for what so that's
where polymer molecule looks like there's a government model of polymer the other all this is more use for physics purposes if you want calculate dynamics the dynamic papers that correspond to the wall of the dictator bikers who was 1 of the great Tennessee this country for the right moment and there is a paper by by fertilizer rounds and there is a fellow of terrifying troubled by the name Sam and you can look at all the salt if you want and if you look at all of the stock back a little challenging but they discuss polymers movement solution the model for a that's a strain of the it's quite common law and space between the spring and springs are attached to the the sort of way this distance well you don't stress friends too much they fall back but there is no for its controlling the angle between adjacent be if you try to build this you discover your mom has tried the springs and face angles with respect to each other as well as the polymer equivalent model does not have that feature all I discussed last time some of our model works the other is a great deal of work on models of polymers in that solution these lots and the anymore ,comma complicated models there is a will find out how long it would take you outside the domain of course but which traits polymer molecules in dire solution so here is entirely solution there's Baltimore molecules and dialup solution molecules are far enough apart relative to its typical radius Hall molecule what I just dropped remains Orangina called the radius fall of gyrations will talk about that somewhat more unless you want but the key issue is that are at distance between molecules Over authority typical molecular size is very large that Archie is somewhat imprecise it's not like the radius of ball bearings these molecules are a floppy each 1 has a somewhat different size for anymore they don't have sharp edges because there's a very loose balls not nice and round through what happens to the yard after a kitten has found played with it for a while so here is a Paul oils and therefore part because they're far apart you can imagine how polymers effect for example viscosity the resistance for solution by calculating what 1 molecule does and then just multiplied by the number of molecules the best value solution now suppose you stir in more and more Wallace feels like an insurance you're worried about the as you added more color more polymer molecules eventually you get to the point where the distance between polymer molecules and size of molecules is some normal life wanted to at that point the molecules start to run into each other now the 1st question you might ask is well they started running into each other what they do and there are 2 answers for very long thought there was a major they literature which got somewhat the worse alliance holds for and 1 answer is that runoff concentrations instead of having it all feels like this you have molecules holding themselves and neighboring molecules that are also holding them but they don't go through each of whom they sure this is a
very open structure if I have a polymer molecules here and you could see it and I fire laser pointers through molecule you will get a polymer strand about places 3 times some number like that on the way through and most of the space in open sold and therefore I have several polymer molecules in principle they could go through each other we now what effect they have run concentration so that you are no longer a dilute solution of polymer coils passed through each other and become intermixed well it's 1 of the alternatives and that's the 1 that nation 1st if we want to talk about how polymers moving solutions well there are several answers and they all go back to a question how we model things watered down forest what is the question What the dominant forces and what the other is the nature of the motions of all workers this work is to use phenomenology there is an actual experimental Americans to tell us something about what is going on solution however much of literature and perhaps less the literature you're about to read book much of the literature is very heavily influenced by a small number of models classes of models and you will read discussions of experiment in which phrasing are used and the reason the phrases are used is that the authors are advancing from a mental image of what is going on all resolutions and from a mental image they get answers so let us look briefly at the image but I mentioned her and rice and curry with rice Moore was the 1st theoretical models help always single change and what they said is here is a single it's sitting in a solution we put a flow field and the flow field said rapidly here and more slowly there so this is a velocity diesel acts and you will guard the niece of acts that direction the the city is not zero-tariff called here now we're talking about liquids was if you put a sheer always it floats you seen this if you stepped in water on pricing you start to fall over ah but water touching the ice is isn't moving the water touching your shoes isn't moving but between into the sled and that's what's occurred the current would ask for what happens if you have slow field applied to liquid the 1st answer is there some sort of gathering velocity the water within the polymer solution the tolerable molecules and their closes the Paul float along and drift with if you throw up all his wallet or watch twig floating down the creek a small river and the water is flowing you see floating objects just bob along the water however and you may have what is this if you have something that is close to shore at the current is weak out in the middle of the stream current is moving more rapidly and 2 things happened 1st of all those moves fast floating objects that was fast because the right up against the shore and 2nd if you watched carefully the Lotus rotating wire a rotating well Apollo molecule the water here is moving slowly water there is moving more rapidly and molecule here on average is moving with the flow but he said is moving more slowly than their wares backwards with respect to this side is moving forward and therefore the whole body of molecules rotates in the year yeah and that rotation released acts friction and his wife Diane would always increases discussed all this is Kirkwood model I have this all of the theoretical details of how you
treat this hydrodynamics the important thing is that I wish to bring up those having said here is her Cohen and his model you can then said let's extend this to non-binding solutions we think they've the Kirkwood with picture -dash of fighters dynamic Polish and we can say Here's copolymers chains and a 1 of people moves that influences influences how the neighbouring chains move and have hydrodynamic interactions between whole college and you can carry these calculations out to fairly high concentration and if you do that you can make predictions these are difficult calculation on 1 hand if you're not careful instead of getting good answers you get tired versions as you get integral security infant the problem is if you do carefully you can avoid those and you get roles the ,comma acres of paper and fortunately there is now a computer algebra instead of you doing the entrepreneurial computer expansion 82 12 thousand terms in the fall of Romeo and combine them and not like to 12 thousand Polish terms upon normal life on the computer lost do with those of more accurate we can do it and so it can actually do this approach now there 2 other countries and the 2 other approaches come from 2 other pictures of how policy July a lot of approach is start very real old jazz and his real gentle you may have what the following molecules real Jell-O show of you have a real and where the molecules stick to each other touch each other they become fast and faster organics synthetic processes for example you make a poly crawled in general and you actually those bonds are kept chemically cross-linked vary in terms of available Federal Energy Europe only so here is a JAL and I have put into the the common goal of polymer chains and I ask that prospective drawing followers winding you know how the Apollo well it's basically we can't move sideways because of the move sideways even modest distance he runs into another polymer chain all those Polish fastened in place to each other by covalent bonds the the accident place except this 1 of the 3 so-called continents sideways all of destined for parallel moves like now cost parallel to his own length is tricky this is in the region with and with Paul Newman moves backwards and forwards all it confined testified gaps through which it move but basically most of the following is mostly constrained to moving parallel along its own way it's sort of like a round backwards and forwards but outside imprecise because this water skin is actually fairly can be fairly large relative to fall was so ensconced some movement sideways it's not that can't sideways but also have a lot but this motorcycle gratification from me and from what I have to record territory to crawl the move back and forth and now we take care the interesting theoretical gas from pacific was acquired guests of the chance to find this is no longer rehearsal us for the article was a Nobel laureate for his work on people overstaying statics encourage work on liquid crystals and such any major gas if we go will polymer solution we can use this picture now ,comma solutions is different from jail In the all Australians and they christened crossed lady reactors around each other however they here that is
certain is that we have points here there is a point that called and entanglements and the notion of entanglement because wrapped around each other he is that on a short timescale the entangled looks just like covalent bond and therefore I have this year the policy change interest the neighbouring chains are Colorado bonded to each other so they can move on a long time scale but a short timescale this chain of interest is not reasonable and therefore chain of the interest of approximately speaking is constrained to move backwards and forwards along its online well once you said that if you're clever you can do all sorts of analysis and make all sorts of prediction a certain set of the predictions the remaining come out of the break in essence come out of the fact that the people were doing this than previously worked on critical phenomena theory is fine and critical phenomena theory you find the assaults Stanley Hall so that for example you have a specific and the specific he close to a critical point and he discovered that the specifics of the depends on the difference in temperature from critical point and some power this is a critical export people generally don't try to calculate pretty fair but the crew in this case the specific heat as you approach the critical point the specific the diverge also if you look at the lake with a liquid Neeraj critical point becomes opaque In addition and this is actually a very practical materials issues there lots of liquids near the critical point home extremely good solvents for all sorts of things they otherwise would not have dissolved and in fact there are people who sell even carpet cleaning services were at the solvent they used his carbon-dioxide marriage critical .period pulls out all sorts of stuff that you could not get out of the very clever use of basic physics however was to think that this is an appropriate relationship between variables you look at something like the sedimentation coefficient that we talked about last nite and you say that sedimentation coefficient .period descend on the concentration of polymer some power end of the molecular weight of all that is on power and if we have a solution that is concentrating often allegedly looks like this we can calculate the powers and that's what because this is a scaling there is a feature despite all a lot of areas of sedimentation of versus a loss of concentration concentration in this sequence Asian is correct guidance should lie on a straight line because that's a general features Powell as if you have a power law and you put it onto a lot lot plot instead of having funny curve you go straight line up and that is exactly what the the channel model is for all sorts of transport coefficients is predicted the power laws associated with Transport OK that small number 2 mom along with the hydrodynamic models based on taking her Reisman going concentrated so model number 2 is the division models there is a certain set all in the 1st set of models for applying what I call a it's solutions Terkel worry they are applied war well we started out with same events finding would care about flow-through said that same many ideas because if we go back a century flow-through saying is actually an extremely efficient way of purifying water and you drop stuff through sand perhaps you with things that cause or whatever flock you fall of solutions and Sam flow is actually extremely efficient and filtration just before water chlorination which is what we now use the United States William sand filtration and reached a point where it was almost as good in terms of removing harmful bacteria and other materials wasn't quite as good and was much more trick here and more expensive so we now use water chlorination keep things waters but since flow has property but I doubt the Council object here and I apply force to it "quotation mark through holes between sale going this object moves to create some weight boss momentum into the liquid but the morning water tries to push on the sale of sand particles in the air which refused to move and as a result more momentum is sold out of fall transferred mechanically and the walls of and the flow is very locally time this is cold screening doesn't currency and that and the result of screening is that this way this motion of water and on what article instead of falling off inversely is the distance that theory wandering straining the fall off his chair you minus half of our over priorities as the 1st line it's an exponential with distance and this means that flow was confined to a very narrow areas and the entire set of models of your colleagues called him all the more they and it's assumed these molecules free-floating behave the same way and you can then a series of calculations on what you get from all dining now I am not going to do theories of all the exemption will also semester I am going to point out that but there's a certain amount of language that comes out of these models and the languages used you should be realized that people are using the line with their thinking back particular hydrodynamic models whose applicability has to be tested Oh yes ascendant model there is another piece of language comes out that I've already said last lecture and the idea of most of all is that I have concentrated Polish solution is very kind he said and I have object trying move through solution the object testifying holes gaps between the polymer chains that are big enough to allow it to move well of polymer chains are completely immobile you have a physical chemical shall where you wouldn't cross the following the breakaway from prayer promises them this is a very sensible model on how things move but there are people who carry it over polymer solutions were these crossed these chemical bonds there and they have asked how would long it I have spent a certain amount of time discussing models and the point of models is the discussion I just gave you is applicable "quotation mark systematically everything we're going to talk about the book and there are forces I'm going to keep reusing molds and the language I thought I'd show a more systematic having gone there was go back to work text and let us go back considering phenomenology of sedimentation what I show last time the seriousness of the crime figures in reacted to the news that we just have a polymer solution Paul language we put it in a centrifuge and we asked how fast always said what we find assuming fall "quotation mark advances in Seoul is they can be so we spend the centrifuge followers from precipitated boss there a sedimentation coefficient that describes the rate of fall and the sedimentation coefficient is a physical transport property is independent of how use Howard's understand announced on forceful grant field is an plot against concentration because this goes down and if you look at a much heavier Apollo oil In dialed solution but has gotta change sediment or but if you increase the concentration the sedimentation coefficient falls more rapidly forward chaining them for a small chain that is in some sense the big chains are more effective at getting in each other's way the small chains are getting in each other's way a and Southeast intersect and have moved the measurements and some of the things they can cross In general measurements extended out here Foreign Office a very firmly it's obvious they crops indeed there are theoretical predictions March concentrations instead of saying the current across do might say predate the current emerge the experiments home were conducted out to the point where you can certainly see curves reach each other but beyond here there is a question of what now the several other things you can do and we are not going to advance to Phase 2 . their teams and 1 of the other things you can do say Well a polymer solution polymers are effective at inhibiting sedimentation polymers are also effective in increasing the viscosity of resistance to boring if you go back to what I discussed last time I said sedimentation rate was a ratio between applied for what could be the centrifugal field it's really big object stressed gravity as the drag coefficient of the 1st 2 years during television after the reconnaissance this ferocity of the solution of the radius of sphere and this gives us they said invasion rate that's not a sedimentation coefficient that I find this out but a lot of viscosity the slower the object will sink with water and ate up the small or will be in the center of the case and therefore you might say Well yes the sedimentation is slowing down it's slowing down because you're making the solution of this yeah you see how the argument well we can look into -dash 13 and today 13 is 1 of of the few experiments cited where people measure not only South Asian cold but also led the discusses solution and what they find followed Lawrence's viscosity goes down it increases all around the sedimentation coefficients also goes down recent concentration but not the same way and well an intermediate concentrations there is a region where the objects of settlement and more rapidly than you would have expected viscosity of and then a large concentrations in years into her word that is the sedimentation rate is governed by the macroscopic viscosity solution this summer look ,comma and got back together and technical name is this is the whole reason entrance and the issue and every entrance is that you have some systems in which there is a domain in which this macroscopic viscosity does not govern how fast things move on a microscopic scale but it is always domain it's not unusual low concentration it's not me who who I concentration but in between there is this region or particle motion is not covered by Wisconsin 3 entrances relatively rare phenomenon we have to 1 of his 1st wife abuse I'll tell you what I ask of him well 1 of the things that can happen is you pushing ahead page 25 are you could say she if we make polymer molecules Our call for bigger and we measure sedimentation the bigger the chains a more effective they are getting in each other's way now is the effect due to the fact that your man making the molecule you're watching bigger and bigger or is the effect of the fact that you're making the surrounding chains bigger and bigger .period dropping mural wall had crawled sedimentation the imaging probes that they had disappeared long chain whose sedimentation rate we're going to matter is surrounded by other chains if these changes are all the same size and I make the change bigger and bigger well this things here 5 loss after the indicted Lu solutions the larger chains faster than the smaller chains verified plot sedimentation versus concentrations if I may call the chain's figure but the current passengers of see falls more rapidly and now I ask is falling more rapidly because the chain and watching against bigger or is at fault is this dropping more rapidly because the surrounding changed again they the 2 possibilities both things could become once How we Tested this the answer is we have was a chain of pros were going to launch a molecular weight we have these more Matrix Chambers molecular weight and we make the approach the Matrix changed differently than molecular weight and then we can change the molecular weight of the probe or molecular weight of the matrix independently from each other and as we do this we can also change the concentration of the Matrix project supposed to be all by itself and that you don't really have to have only 1 approaching solution but if you only have a tracer concentration a locality raise you could ask how promo matrix will last seen in Figure Tuesday at 15 that figure to be at 15 shows you above and below figures Parts a and B. it shows you 2 different molecular weights of matrix change and then you look at a series of different probes more with the same matrix to change race what you find and we're looking at today after the and we have various different molecular weights training and we look at 2 matrices and what we find this sedimentation Virgil Cole and so here is a small world through face-to-face streets the as far as the does that and this is the small and if we make molecular weight of 12 large well if the matrixes dialup large probe said more rapidly we increase the concentration of the matrix the sedimentation coefficient of logical falls very definitely involves more erratically in the 7 pages of vision small world and into curves crossed you can see it I think the lower and so at large concentrations of matrix a large problems on this means that costs only a small part of the United curiosity if you look at Her figure in what you can see these services .period across many not exactly at the point that they certainly crosses something resembling point so were given matrix pall over it there is a concentration that which endangers polymer to recharge old pros to the same month next to different sections of the probes all settlements at the same rate not separated watch yes is and while the 2 of them with following the death in this not the same that I don't think you should be the answer is however when you explain that the answer is that if you have very Bob In a few years a there are 2 different matrix followers but the -dash lines referred to a very small matrix and the very small matrix polymer slows old trains down about the same extent that's why they hashed herders Hartford paralleled June but if you make the matrix polymer bigger you get a solid and a somewhat martyrs of matrix polymer gives us the figure the shows a really big matrix fall more and you get this behavior very dramatic but the answer is if you have a very small electrics folders you don't see this effect all people who believe in and models would discuss this in terms of entitlement and I said if we have a very small increase and different-sized problems we see in the next room they curves like this and the reason is that of the matrix Palma's artillery short instead and has tangled structure of life vests with very long chain if you make them dangerous ball very short most of the chains are so short that they don't have heroes of entanglement points and therefore not tied together and the solution and small matrices small light weight and on his own entangled but large matrix that is his knowledge and but large matrix element of the solution isn't intended NYT asked what she watery effects within this model to determine if polymers and and on and the tools 1st of all the polymers have to be long that is the march along the length finds that all the colors are wrapped around secondly the policy after the close together and all of that you get multiple entangled points along the same track now if you die Luther solution these invaluable points moved farther and farther pork pot and eventually small concentration lessons on critical concentrations the policy solution his tongue is final Tennessee dragons the start of all the solutions and that so polymer is too small words to dilute or some combination of those 2 the polymers and not intentional but if you make the concentration on the molecular weight margin you get entangled and then stated to qualification I drew entitlement points so they loops that's pretty things drove black people there is absolutely no evidence that those little work causes hanging but is a pretty waited drop so you can see what's happening and the image is consistent with an interpretation of phenomenal . 2 when I said this scene last season seat made deceased or you do not get carried away with the the impression the trail relations from on entangled to entangled behavior cast the shop most theoretical models do not predict whether the translation from here to there is shock for broad but what theoretical model I know all of that makes a prediction on this says this is what is called a percolation Trans World nation and percolation transitions are shot however the data doesn't tend to resemble that it's not clear saying it's a percolation France's position is right and so he wants a transition is broad well that's certainly consistent but most serious just don't treat their transition region of all they talk about how we are well into the following tangled regime with the chains don't or we are well into the entangled regime chains are really in 1 thing that is you should realize there is the highest possible concentration you can get the milk you cannot get a higher concentration of polymers of all Paul Ruiz no sold and consumed about what you 1 gram and in the melt all Europe the highest concentration you can get In the Mouth there is a lawless molecular weight and you see entanglement behavior or whatever and then behavior actually years and there is given melt there is a distance between the Angolans themselves he Synovic of Bolton's performance measures along change and if your college assured that they don't hang if you die lose the chains cancel he becomes much shorter distance between environment she points his retirement in chains and molecular weight me for what is called an angle of behavior in this side dish on picture goes on and that he can get through the total savings -dash alliances to and corresponding changes that are too short to be entangled at concentrations measurement of 4 days now let's shot ahead and we will push ahead years and 16 was appointed the new music the world and the world will watches measurements of sedimentation versus concentration and was found numerically you can see all pictures earlier in chapter is sedimentation coefficient goes the song constant times the 2 miners held onto that's as fresh exponential and experimentally if you look at plots of law Casanova is as long as the you stayed smooth curves that is why I am birds you not see Powell as region is a straight line well you can always say Here's the straight line I revere a straight line as can have a smooth curve and so there's some region which historians Powerwall behavior but you will see that nowhere straight lines your theory doesn't predict where and what concentrations you should seize power lobbying so far phenomenon In phenomenology what you see in earlier chapters whites consistently 1st French exponential so they actually go through data .period I'm however you want say maybe that's true but if there were anything fundamental there these 2 constants the fat and some clean way out of the solution property for example it would depend on the molecular weight of the although Kroll on the molecular weight information and when I show you would figure in the F-16 disk plots moved against molecular weight of Kroll In systems in which the molecular weight of the matrix has been held fixed and if you look at those figures you notice the data while straight lines on some faces there are many points that will prove very much but 100 cases some of the points and straight lines through the points and therefore they also knew are variants themselves smooth way as you change the homes for example was size probes now they're smooth way depends on what your matrix and probe aura and if you actually plot holes measurements on the same graphic looks rivers status because there are other factors coming in on the pro molecular weight matrix like the way Madam however we can do and that's the significance of the year to at 16 the next step of the phenomenal logical analysis which is a ask very nice people parameters of the data but the parameters show any systematic behavior available .period generated by rolling the dice the answer is that there is systematic behavior on if you compare curves into deaths 16 you discover that as you increase the molecular weight of the matrix as you increase the molecular matrix the alfalfa is that and so there is a smooth dependence on molecular weight of partly state dependence on molecular weight of major and that's about as far as you can carry that some analysis UK I'm going to give you a specific additional reading assignment and reading assignment it is for people trying to enter footnote 5 and as long as it is it will review letters which was almost and this was a macromolecules wealthier publishes all sorts of physics but it certainly does publish some homework to realign their enactment molecules with users who were yet and if you look at each of those papers and the reason you're reading each of them is to get some impression of what the actual experimental data looks like as opposed to very compressed summary is compressed Yellow books 500 pages so the book if I printed out is about getting thing the papers on which the book is based more than filled filing cabinet and what I did to write the book was to compress this year out of information down to something much smaller using this year OK we're done with sedimentation that I have a theory that the director of let us pushing him and let us push ahead chanted threats and in Chapter 3 we talk about a lack of Greece's to notion behind electrophoresis is actually quite small all the notion is if we have a lately and we apply appliances like an electric fields to link and there are charged objects late with the charge objects move however the actual 1st experiment was quite different yeah goes back to the center and my parents and there was to basically filled with by particles with me and there was no water in the lake in the water had been reasonably purified costs 200 years ago whose distance distilled actually pretty good there and the water contained no no less if you applied electrical field liquid it and this is the answer that electrophoresis is actually an extremely complicated phenomena and understanding what is happening in Malacca Fred experiment is a whole lot more more complicated than understanding sedimentation what do we learn how hours work OK the original electrophoresis experiments as backed felt like they were sailing in the modern spontaneous elected ready experiments on Polly electrolyte were dominant bulk solutions and if you do electrophoresis and bulk solution to have this little problem you have is a large object Your flowing electrical current through it there is resistance gets hot just like a wire will get a lot of Pearson particularly if you're feeding liquid you see the same effect that you see a few heating water make scene namely you get the and rising because the hot liquid is less dense than the cold liquid floats upwards water you should by doing the experiment about Celsius because water has density maximum were Celsius and therefore if you change the temperature just a bit density doesn't change during the modern solution then the lot more modern solution really 2 and 1 as saying will run the experiment inside shell and Crosslin gel just sits there and the Crosslin gel suppresses convection because there's no opportunity for using what the other solution is saying instead that the experiment you all solution were to you this far apart wilderness inside capillary can this distance from the sale 100 my problems in very tiny distance and we have a very small vessels so there's good hydrodynamic interaction with the walls and this suppresses convection quite effectively concept we can make convection kind of go away we then asked what is happening inside the 2 of his malls it's filled with water there has to be some solving it inherited from the most positive and I applied electric field which means that only the Sunni-led as I have been doing electric street or something similar because I have to have a current flowing out of the water in the solution and I solution in the wire we might battery actually at Busan electric chemistry get current flowing as there has to be kind everywhere so there's a lot of things and this is going to hide its What can we don't see but there's an electric field here and the electric field applies charged object charge of you the yes you the description just giving you some totally oversimplified what what else is going on at the same time "quotation mark gathered gravity but actually that's negligible if I drop you water float because the densities of war and the gravitational forces so small I thought that it would be more the next thing that comes along this is bonds positive charges the solution has to contain salt and out here about as many false charges and therefore the electrical forests on the solution here is about 0 because the negatives for what was positive and the negative ions is 1 way positive appliances otherwise Nova any reasonable macroscopic more volume than that forces 0 there is 1 place where is not true and that is the region close to the positive the Poseidon lineouts positively charged it tends to attract negative violence from surrounding solutions intends to bring held positive sign onto my figures said areas the city In each of these negative violence has a negative factors were still pulling back away there's electric field now what is this electoral force developers to the 1st years of positive charged with are objects and there's something called to find screening which says that preferentially urinating on but I am directing the negative ions this way so there are more islands on this side of town exercise and I drank from and because the morning Ireland's used here they create an electric field which tends to brands positively charged object that opposite to the direction in which it is prime mortgages these negative ions does experiencing electrical forces pulling back and because the IRA the misplay it creates a weight in the surrounding solution you creates a hydrodynamics flow the polls on the side In addition the zones were worried by Ontario directly in front of the straight into the positive object might have a car truck collision in which the negative Ireland plays the role car protein plays the role of truck and all of these effects sketched do the same thing they slow down the motion of of the positive now some reason effects this hydrodynamic interaction would exist or just looking behind armed King equilibrium in solution because the united on this the Metroliner or solution would have had a dynamic interactions with their shot order is going to leave this arise because there's an applied electric field on the solution but the electric field seen by the Ohio is not the same thing there's dielectric polarization advocated well know there is a more effective because there was fair 200 years ago but terrible walls of 2 and most objects in solution and pick up charges where they have charged groups on the services analyzed and technically those positive groups there are always reluctant on negative charges that involved in the service of the 2 they could be positive charges underwriting and the negative because they released positive charge is solution I know most of the solution is approximately neutral and then fossils history at the souls of year but very close to the surface to 4 walls of the 2 the negatively charged they tend to attract positive charges the wall they don't bite them we won't be neutral but there is a surplus of positive over the negative charges in solution follows the wall the fertilizer now Anthony electric field the electric field tries to pull these charges the Wall charges that line the walls mechanically reject those charges just because they're nailed down quite literally the bolted to the experiment where operator these charges on the the American charges move that way a few of there are and the positive charges only if they are going to get the facts of the electrodes clause Moses In is justified last most assume that evaporate the water flowing through it in 1 direction reads whereas the flow always positive charges positive charges down there this way and if the solvent sitting here wall it sees this flow of positive charges that way Air doesn't see anything else an therefore warrant this would be the year of the Dragon along this flow at the wall fortunately to form of flow field of view positive charges is the same the wall everywhere and some this fall does what is called a "quotation mark long and chose along this way and if it drugs along with the same speed all the way across the the that's entirely different flow you introduced by applying pressure if you tried introduce a flow not displayed by introducing fracture the solvent at the walls is stationary the soldiers in the middle of this fall in that way in the pipeline velocity of solvent furnaces the position of pipe there a velocity profile fast in the middle of the road walls that looks like a parabola plus flow is central to the electrophoresis y because fun clever I arrange things so the positively charged object is this way I have switched charges around so 1 loans that way and the charge objects instead of going through stationary soldiers are winning through solvent that is moving in the other direction and sullied short of capillary because I have Austrian against the flow takes a much longer time additional capillary behaves just like it was actually much wanted him In can that this constant although no this is actually a philosophy of you now if I say charge object is trying to battle against the flow the flow is moving that way opposite well if the flow was slower than the speed of the charge charged moves this way but it means that Lavery slowly and so spends a long time and the capillary tube and will get next time why this isn't in the entire evening right plug flow faster than the motion shot In the object whose seat on the way 8 yesterday to the electric field on this positive objects crime during this way but the hydrodynamic flow is to the asked and so it's still a brand that way down you may think this is more about the real fast river and if the motor boat has a powerful engine involves Australia and has a weak engine is dragged down 10 are we going this OK we're out of time but I have gotten as to how the electrophoresis works you should very definitely for next time ready electrophoresis chapter are there are 2 pages in the office there the footnotes and will fight and 1 is in the severity of the injury and the research to cancel very interesting thing and then there's the paper by a tripod and crumble I've met her I'm that and you should actually look those 2 papers and see what they did the 2 papers are too long to between now and the next class but you should glance at least skim through them and see the types of measurements that were made even if you don't follow all details and the next lecture will discuss the electrophoresis this is the lectures 3 of physics 597 the phenomenology of polymer solution dynamic


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