Before I start though let me you can ology
the folks that really are doing the work
a particular way show a way into a
Martinez alexy dealer coat Soviet interior
who are students and postdocs in my group
right now working on these problems
also I'll be talking a lot about
work done by a former students and
postdocs though you Davidson in June Jiang
who are gone on to better things and
then I have you know a very
distinguished group of
senior colleagues who helped me a lot
from Japan and from Swarthmore.
OK So the plan then I want to talk
about three different systems.
Crystals there are tropically crystal
drops in liquid crystal polymers throwing
additional youth some old experiments
a little bit of the old experiments which
I'll go through very fast they're
published you can read about them and
I just hope we hit on the high point and
then I want to tell you about three As I
said experiments that are in progress that
we're still really trying to understand so
let's start then with the Monica crystals.
Which I think I just want to just make
sure everybody has the background about
this basically we could crystals there
are the critical ingredient is Planck like
molecules and if you put it in water then
they you know when they see another one
they tend to stack poker chips and
they make sort of broad like messages and
then depending on temperature and
packing fraction or concentration you can
the message in the basically interact to
make liquid crystal phases like the magic
phase of the kilometer phase and
this is you know so using this phase
diagram here you can see the different
phases and coexistence regions and
you know we'll be doing I'm going to only
be talking really about the Maddux today
but there's some interesting things
that happen when you go to the Columbia.
Which.
You can talk about offline
if you're interested OK so.
You know there's a lot of reasons that
one might be interested in these one
first of all they're water
based liquid crystals and
so in principle you can have this
liquid crystal technologies that.
We associate with the displays that you
can apply it in sort of biological media
and so you know I think there's a lot
to be done potentially there sort of on
a fundamental side it's kind of different
than the traditional from the tropics
in light tropics in that they're sort
of this two levels of assembly right
the first the assembly into the aggregates
and then the aggregates assemble into
the crystal faces and so there might be
some interesting physics lurking in that.
There as well and the other thing
which I'm going to focus on
today is that the end of the elasticities
of these systems is an isotropic so
do specifically what I mean there are so
this is.
Basically you know the liquid
crystal can have less distance and
you know the famous splay twist and bend.
Less this is the of the director and
associated with each of these distortions
is a is a elastic constant and
if you look at the thermal tropic
systems it's about the same OK but
if you look at the core monic systems
what you find is that the twist elastic
constant is much smaller than
the other two OK And so essentially
they can twist easily and so you know
what we thought when we started working
on this is well OK let's take these things
that twist easily let's drop them into
different containers with different
shapes different boundary conditions and
just essentially look to see what
happens OK And so the way we look.
When we use a number of different
techniques to look Randy already talked
about this I'll just remind you right
the you know sort of certainly one of
the biggest techniques that one uses
in this area is polarization optical
microscope A where you put the sample
between crossed polarizers and
you know when you see when the light is
transmitted there's some kind of a fire
for instance was which is an indication
of the direction you know.
How the director is pointing and so.
In our experiments you know will will
will make those measurements and
then typically we might make a model for
what we think is happening OK which has
parameters that can be tuned such as the.
Elastic constants and
other things boundary conditions and
so on and
then from that model we will basically
do a sort of a simulation experiment and
use the Jones matrix transmission.
Techniques to calculate compute
the transmission pattern and
then we'll just compare the compare
the theoretical or the simulated pattern
to the one we observe then tweak the
parameters in the model to try to get them
as well as we said and you know if they
agree pretty well then we declare victory
we see that but that's not necessarily
always true but we declare victory often.
So the first experiment all show you
again these first few are very quick
before I get on to the new things but
basically as we put them in sunset
you know in this case into droplets.
In oil.
And basically we had.
You know with that with it's a fact and
and in this case it had planar anchor and
and you know here's the sort of this
experimental poor polarization optical
microscopy images and this is essentially
what you would calculate if you had
a bi polar structure with these dreams at
the end compared to a twisted bipolar so
you could see that we had
the twisted bipolar OK And
you know there's you know it
was a bipolar it's been seen so
that wasn't that surprising that you would
have that but you know one thing that was
kind of unusual is that the twister was
really big OK And so this is because this.
Elastic and isotropy for the twist is much
much smaller than the other ones and so
even though we have a chiral elements
that are making this structure there's.
Sort of the spontaneous formation of
chiral structures and you know we did
more theory about this and you know you
can sort of I won't go into this too much
except to say that the configurations that
we've got you know were energetically
favorable because you could trade
essentially a twist of the director
near the poles for support OK And so that
little that the system lower the energy.
OK So that's the putting
the liquid crystals into a sphere
then the next most complicated thing maybe
is to put them into cylinders and so
we did that and June would Jiang
you know work very hard actually
have figured out a way that we could
home you tropically anchor these C'mon
equip the crystals in the cylinder OK And
then we want to ask what do we see OK And
so we have some inside of what we have but
we might see
those than what people have done with
thermal tropics OK so here's sort of
a couple of configurations that you might
see you know a radial configuration.
Because remember the director is
perpendicular in the how many tropic
anchoring to the surface or the most
common one is the twist you know escape
radial And so basically you know but
it's coming in at this from the edges and
then it sort of spends and
sort of escape the axis and.
So so this is the sort of thing
that we might expect and and
that's kind of what we got except as you
might imagine there was you know it's
an escape or a deal with a twist so we
saw the twist escape radially still have
escaped radio face that now it's you can
lower its energy even more by twisting and
you can twist you know sort of right
right handed or left handed and
there's no preference for that so
again you get this sort of chiral symmetry
breaking because you can trade twist and
energy for
more if you want to bend energy and
so you know you when you make these things
actually you don't necessarily make one
domain one kind of twist escape
radial structure you you cool it and
suddenly you know usually all
these experiments were star.
In the isotropic phase and
we cool it down and so
you can get you know domains and
defects so we've got sort of a whole
sort of sets of you know again you can
have different escape directions but
now you can also have different
Felicity associated with that and
you can get different kinds of defects and
domain along which I'll.
Just leave you with OK then the last thing
that we did that I wanted to show you by
we're background really is putting
them in cylinders again but
now instead of having homing in tropic
anchoring but putting degenerate
planar anchoring which is what it
really would want to do in general for
these chronically good crystals and I
should say that you know this is work that
I'll talk about but you know well vertigo
and Mohan's groups did of independent
sort of experiments on a different
canonical good crystal to look for
the same kind of phenomenon and so you can
read about it in both these papers but
basically if you make a if you put these
liquid crystals into a cylinder might
think the simple this thing you would get
is this all just the sort of it's parallel
line on the surface and they you know this
has the no distortion if you like but
when you look at the sample between the
cross polarizers you see something else is
going on there's some kind of twisting
at least some kind of deprivation and
it turns out that to
understand it is we had to.
Look.
Think about the Let us that is the.
Another term in the last this to
be called the saddle splay term So
normally people just focus on the splayed
bend and twist but there's also other
terms like the saddle splay And
essentially what the saddle simply.
The significance of it for
these experiments is that it tends
to favor alignment along the circles
of the cylinder OK And so
this K two for this elastic concept for
saddles glues large and it's going to
favor this kind of alignment and you
might you know when you combine it with
these other elastic module and you can.
Sort of the lowest energy venue you
might get you can get twisted kind of
structures like this and this angle
beta for example you can predict and
it's related to the saddle sway but it's
also rated to the twist elastic constant
in this case three and so on and so
again to make a long story short.
We.
Did the math and ultimately did these
similar experiments in Alberta's group
where we determined this angle is
a function of distance as you go from
the edge of the capillary to the center
and you can you know by fitting to these
kinds of curves we can deduce that indeed
this you know these models which are put
in sort of the subway can work and
furthermore you know you can and
you can estimate for the size of it in
terms of quite large to discriminate with
a place to put it so
that the sort of stuff that
we publish and for now want to tell you
stuff that it's sort of in the works OK So
this is work by into Martinez spearheaded
by him and basically what he wanted
to try to understand or think about is
what happens if you put a little particle
into these C'mon to look at crystals for
example how do they do you and
you know hopefully you can sort of
see this is kind of an interesting.
Situation because the particles are going
to be it's not just going to be like
a particle in water it's going to be
a particle in some field this pneumatic
director field if you look at it right and
so you can have different dressing if you
like the particle by the director field
and so for example you can have it so
that has the same helicity on both sides
of the earth of the particle this is I'm
going to call this close you can have
it so that has an opposite to the city
on the size of the particle and called
it close to these are different you know
energetic with it a little bit different
they've been studied by this leaning group
and you know these are these are pictures
of them in from our microscope and
you can just see you can easily tell the.
Difference between them and
so you know basically what I.
Wanted to understand is sort of what
is the fusion around and dynamics
of these particle if you like they're
kind of like an ellipse that way but
not really right so the lip so
it could rotate and
this one that has this
configuration on it and it doesn't.
And so you so so so
he built essentially a cell that you
can control the temperature in and
we can load the B.
and D.
A C.
G.
in this case the because
of the you know and
you know we can rub the glass to
align it along a certain direction
shown here and put in a very
small amount of particles OK And
these particles are very
common when they go away and
they ensure that it's very good
planar boundary conditions for
the director along them and one important
thing that he was able to do is he was
able to do experiments where the particles
are relatively far from the wall so
we can measure what we think is mostly
bulk of facts and then the kind of thing
that one wants to look at is is there and
I saw trippy in the diffusion.
For example parallel and
perpendicular to the director.
Are there differences do that the classic
one or the class two kind of particle in
this monicker Crystal because they have
a different dressing if you like right and
then as I'll show you there's kind of.
Interesting dynamics to people
from subterfuge of motion and
use of motion that one and you know
it's different than you normally see and
so one can try to understand this again
in terms of twisting in this in this
moniker Crystal So
let me just show you some results so
here's one that's focused on
the diffusion and I saw a trippy parallel
versus perpendicular to the director OK So
here's the meat it's the displacement
of the particle versus time and
the red curve is parallel to the director.
The blue curve is parallel is
perpendicular to the director.
And so you can extract in the long time
limit the first thing you do is sort
of extract in a long time limit
this diffusion constant and and
you know the you know it's quite high and
isotropic OK it's
quite a bit more than it's been
predicted or measured for example and
in thermal tropics of course it's not
exactly the same configuration but.
So we thought OK well so what else can
we learn about the chronically crystal
from this kind of measurement and
so one thing that.
Engine realized is that we can relate
these diffusion measurements to
measure and it's related to the so-called
with discussing the case of that in
those measurements you put a little or
so between you know in a plane and then
you hear one of the planes and you know
you can have this your direction there but
you can also have the direction of
the director being different and
there are three sort of viscosities
associated with different
you know the shooter direction and
different directions of the director and
if you think about this a little
bit the motion that's parallel to
the director is basically sample wing
mostly something like this would
be here in the motion that's perpendicular
is sampling some combination of this and
so you know one thing that
is you can interpret this
within reason because again this is
a chronic and so people have done this for
thermal tropics that the twist wasn't
that important in the system but you can
interpret this as a measurement of the or
an estimation if you like of the user with
viscosities the amount with the pistol for
the first you know it's the first time
that people have done that.
Then let me show you a result so
I thought I mentioned right in
the beginning that there's two
different classes of dressings for
the particles class one and class two and
so these are measurements this is you
know very painstaking measurements
where he measured the means greatest.
Placement versus time for
the to be different you know particles in
the two different classes again
both parallel to the director and
perpendicular to the director and you know
what you can see really if that this class
of two one is clearly diffusing faster and
has a smaller and I stopped and
again very very crudely speaking you can
think of it well we've this particle
is just bigger the constant and
bigger along a major axis at least and so
you might think certainly there would be
if you had slower and also you might think
that there could be a bigger it might
have a bigger and I asked for the bigger
ratio of this size to decide that's
thinking a bit like an ellipse only.
And the last thing I wanted to show you
about this is going back to the time
scales and so
here it went to what we were and
who was interested in understanding
is that if you looked at
the sort of the relaxation of subject you
said behavior to diffuse of behavior.
For the cases where there's motion
parallel to the director it was pretty
fast comparatively fast of the order of
the second on the other hand if you look
at the other the other direction really
was pretty pretty slow OK it was about
one hundred seconds and so why why is that
how is that why is that happening and
so to to to.
To make progress on that then he
essentially dug deeper into
the problem and he looked so
this is on the left hand side here I'm
showing essentially the director field
in terms of the display so it's deviation
from the background splay twist and
bend OK this is just for
the particle around the particle.
When it's just sitting there.
But then what he did is he took the
particle and he moved it a little bit and
then he recomputed the.
Director field and then he looked at the
change OK and he looked at the change and
he resolved it into the change
in the display the change
in the twist and change of the.
Then and this is for
motion perpendicular to the director this
is promotion parallel to the director and.
What you can see certainly for parallel
is that there's a big twist effect for
the two it's OK so
maybe the twist is important again so
we went a little farther and
we essentially just took
we took one of those right out
of the design book if you like.
But that's a perfectly a plot but for
example you can figure out
a relaxation in the lab a time for
going from one twist direction you
know for relaxing twisties equilibrium
configuration and that depends if
this in you know you can do that for
other you can do it for the other things
to splay and bend and basically you can
that will depend if you put it on the case
of the slab This is the thickness of this.
But also it's got the.
Electricity so
seeded with that defamations And so
if you like this kind of give you a time
scale but I think you perturbed the.
Put up but it's how long does
it take to come back to it.
To its equilibrium structure and so
this might be something you would think.
You could associate with this relentless
long relaxation from sub diffusive
to diffuse the behavior and so
you know taking the again Dia is sort of
an arbitrary thing so I just took it
as we just took this here you might
be more interested in the ratios and
that at least the deal would drop out but
if you put in the sort of there's some
fraction the radius of the particle then
you can get some numbers because these
other numbers of the K one K two two and
so on are have been measured and
what you see is that you kind of get.
Something in the range of what we're
measuring namely that the relaxation
of the twist takes a lot
longer than the other two and
since this motion perpendicular.
In the chronic to the who is the director.
Induces a big change in the twist
it's sort of offers a pathway to
understanding why it's slow OK And
again it comes back to the two of us OK.
So that's sort of where we are with
that diffusion experiment.
OK so now I'm going to tell
you another experiment
which is also really involving twist and
diffusion in a different way and
it's like a really this is work
by Alexi deal with hot and and
basically it's in sort of a very
conventional system a thermal tropic
Crystal five C B in a spherical drop with
how many tropic boundary conditions and
so just again to remind you if you have
this here in a magic crystal in a sphere
with HOW MANY CREDIT boundary conditions
then often you get this Radiohead.
You know and you have this defect
at the center well known and but
you know actually there has been a fair
amount of work that's not the only thing
you could get so for example you can also
get depending on the ratio of the elastic
constants in your media and some aspects
of the geometry of the situation you
can get twisted twisted hedgehog this is
an exaggerated picture of that also OK So
Alexis was basically he was doing
some other kinds of experiments but
in the course of doing this experiment
he started to look at drops and
he saw this drop.
And this is what he saw was OK So this is
under the microscope this is the drop.
And you know the thing that's interesting
is that these there's these fluctuations.
If you like of the center
the orientation of the center of the drop
compared to the edge of the drop.
And so.
You know so
these are the fluctuations that
you know attracted us to start
looking at this more carefully and
then what Alexis has done so far is he's
sort of realized that there's a RICO.
Signs of diffusive effects that
are obvious at least the first.
It's almost like it's like
a center of mass motion but
it's a it's a rotation right so
you can think about the.
Two masses on a spring moving right as
the center of mass motion there could be
relative motion so
that this part is like the the external or
overall motion of
the director configuration.
And then there's two other kinds of
diffusive things that are emotional
fluctuation effects that he
saw one is a relative motion.
Again that's like the spring if you look
at the masses moving relative to each
other and then then finally if you work
hard you can actually see the defect
in the middle there's translational
diffusion point as well and so I'm going
to just focus on this one to show you
some results and move to the last time.
OK so.
So you can understand this if you you know
I sort of alluded to the fact that you
don't have to have a radio hedgehog
you can have this twisted head and
so you can understand this
twist as a rising you know.
Kind of a motion if you like of
the whole director configuration
of this of this this twisted hedgehog
you know so you can have angles
that are less than zero angles that is
zero angles that are greater than zero
on average it looks like a radial hedgehog
but if you look at the fluctuations it's
not it doesn't seem like it's that you
can look at the angular fluctuations
this is the measurement you know these are
the kinds of measurements that Lexus did
this is just the angle that Angle versus
time and then you can construct stuff
that we do usually with translation
going to constructive mean angular.
Displacement for example and so you.
See that for example that you have
kind of right away you can so
this is you know angular displacement
versus time these curves all correspond to
drops of different sizes so we look
at the effect in different sizes and
you can see that there's sort of this
regime that's kind of diffuse it's mostly
diffuse eventually this for most of these
curves the explanation is close to one and
then it put those so
it's reminiscent of diffusion in a cage.
You know and
as they said in the subject of regime
the slopes are all less than one but
a lot most of them are close to one.
And then in the Plateau regime you know
you can get a different maximum angle for
the Depending on drops on OK So
we're starting to explore that more and
so for example if you look at this maximum
displacement Angle versus drops and
it's not at all monotonic right so it's
sort of small for small drops small for
large drops but it there's sort of a sweet
spot in between where it's big and
you know maybe we can rationalize that.
The you know when the bottom
when they drop small then
the influence of the boundary conditions
the surface anchoring is important and
it prevents it from moving a lot when the
when the drop is big then the anchoring
conditions aren't as important but
maybe you could argue maybe that you could
you have to move more stuff in the bigger
drop to get the things in the middle and
then there's sort of this
sweet spot in between but
we're trying to understand this now and
to understand it.
We've actually gone back to
the basics a little bit for
the help of our theoretical friends I
won't go through this except to say.
That you can write down
a model of the fluctuations
through which Holger Stark
did some time ago.
But without the same exact you know
without the complete symmetry OK that you
really need for this problem but he showed
sort of that there were conditions and
under which you would
get a radial hedgehog.
Or twisted had gone OK and it depended
on the you know the relative elastic
constants and some aspects of the geometry
so what we're trying to do is to sort
of write down a little bit more complete
theory where we can as a mutal motion and
the goal of this which
hasn't been done this yet
is to make you know figure out a free
energy landscape if you like for
the whole configuration OK so
we can understand this diffusion
of the twist configuration in
the in the center of the drop.
OK So then finally how many doing good
OK OK OK So then I did the last experiment
I want to tell you about is with liquid
crystal polymers this is really
spearheaded by Wish our way
and also in collaboration with you yanks
group who really know all the chemistry
much more than me about how
to do this the basically So
let me just give you a little
bit of story on this OK And
so what the liquid crystal liquid is the
polymer you have some sort of fundamental
message and and in this case it's
R M eighty two that we're using and
it's this molecule here and so you know
by itself it's the long gaited and
it might actually have the crystal
behavior but what you do is you you
you sort of chain you know you link
a bunch of these together OK And so
that's a liquid crystal polymer and
then if you you know again look at
the look at the behavior of this liquid
crystal all over as a function of
temperature it exhibits in many situations
of the similar kinds of behavior right for
regular traditional route liquid
crystals that isotropic phase and
then you go to lower temperature you can
get in a manic phase you go lower you
can get a crystal phase for example for
this system and the temperatures
might be different the range
of this might be different generally when
you when we make these at least we don't
just make it of one length so this is
probably dispersed of the intrinsic.
In the problem that can be important
I'll show you something about that and
then I think we'll hear
throughout this meeting.
On all sorts of interesting experiments
that can happen once you make these things
and you cross-link them OK and
I'll show you
a little bit about what we've done
about that but we haven't you know
I think you'll hear a lot more interesting
things later we OK so what we did.
Is we would wish did is
he basically took these
he made the polymer liquid crystals and
he put them in the drops again.
And then he you know any and he put them
in the drops where they were so fact and.
And.
That caused it to have homey a topic and
conditions again.
And so if it was just him then and then so
this is usually a fairly high temperature
to around eighty or ninety degrees and
then then he let it cool OK you know if
you just had a minor and you let it cool
to room temperature then this sort of and
I should say sometimes it could be
depending on the situation it could be
an isotropic face here or in a manic phase
here it's in America freeze you can see
the defect in the middle and the
microscopy but basically with a monomer.
It is sort of decreases in
size in the crystalline OK So
because of the crystals there.
And so what we wanted to understand
think start looking at is sort
of what happens if we do this
with a liquid crystal polymer.
And so so
we're going to show you is just you know
a time lapse that you know sort of a time.
A picture a picture of what's
happening here is the initial drop and
what happens to is a function
of time as they decrease the.
The temperature that it creates So
let's look at that.
You have the drop and then you can sort
of see it starting to explode OK so
this was just a big surprise when
we did this OK And so basically
if you look at the drop you can look at
it at different points in the cooling and
you can see that it has different
morphology first it kind of rough and.
Then it starts to poke out a little bit
more and then at the end you know you just
it's converted completely from this
the manic drop with this central
defect into this filament to structure
OK and it's all still held together.
If I.
If I do this so I can make this structure
the so we've lowered the temperature
of made the structure now let's
raise the temperature again and
then lower it again what happens OK So
you know if you raise it if you raise
the temperature then basically all those
filaments go back into making drops.
And then if we lower it back
down then they make the.
You make the filaments again
if you look at the filament.
Under cross polarizers for example.
You can actually see that
they're still manic and
remember they're home in the tropics so
they're very they're anchored
to the tropical anchored so
this is kind of like a cylinder and
actually if you look at these pictures
carefully you can you'll deduce that
the center of the you have it's
an escape radial structure of the liquid
crystal in the film and you know with
the defect still there in the middle.
OK So those are the observations and
then what we've been trying to do is
let me just before I do that all of
this is a little bit more carefully but
what we did so what we did is we
took this sort of the ingredients
to make the liquid crystal polymer namely
the monomer the chain extenders and
the cross likers and high temperature and
you keep it at high temperature for
a certain amount of time OK and
that lets this reaction go that makes
the longer and longer ligaments the longer
that I leave it the longer the average
the mean length of the polymers and.
In the sample are but
it's still heterogeneous OK and
then basically we make the emotions and
with this fact and that we can also now
control how much the fact that we use and
then we cool it and you saw this effect.
In the movie.
Now if we.
Can make a kind of a state diagram to
classify what's happening a little bit
more a little bit better so that let
me just run you through this here so
this is a liberalisation time OK So
that basically the longer it is
sort of the longer the mean length of
the polymer is and this is the S.T.S.
this is part of what we've done actually
so you know we did the first experiments
we saw this and then we just had to do
lots and lots of other experiments to try
to figure out what was really happening
which we still don't really fully know.
See but
basically here is we're changing this or
practically as a tradition up
to the C.M.C. which is S.D.S.
in this case we tried a bunch of
differences back and and different.
Symbols here like if it's a black symbol
means it's just dated as a sphere.
This one it's sort of at least was
a sphere and it started to get rough and
here you're starting to get filaments and
here you're getting very thin film OK So
there are actually maybe two hundred
nanometers to the thin film and so
we're making and so you can see so
if you just focus on this region here
this is kind of near the C.M.C. so
this one is making the filaments longer
this one might you know you might again
think that it's basically lowering the
surface tension and pain and so here he
basically you can see the morphology going
from the spheres to the sort of rough and
spheres to starting to make
the filament as you go down OK and
so you know this so
we have all these observations and
then we wanted to you want to understand
what's what's going on OK and so.
You know and it's not you know there
there's there's some beautiful experiments
out there here's one from a designer don't
exclude you know where he has this disk
of fifty virus and it's a lesion
forces he's put into that and
then depending on tuning of those
depletion forces he can get this thing to
spontaneously finger into these chiral
fingers and you know so basically
the what you know certainly the key thing
one of the key things that's happening
here is that the surface tension is going
down and allowing this to happen so
we thought all right well maybe we can we
can sort of be quantitative about this and
I won't I just want to I don't
read all this just basically.
I just want to point out one of the things
that we did is we basically dependent drop
experiments with big drops though of
the polymer to measure the surface surface
tension as a function of temperature and
it does indeed get smaller and smaller.
And these this family of curves
corresponds to different.
Times so
different mean the little darling and so
when it's really long it's also
getting really small OK but
still we're having these effects
even you know with these things and
then the other thing so the thing to
think about is so with temperature
changing we can in chanting temperature
lowering we're going to lower the surface
tension certainly then also with this a
liberalisation time we're making more long
filaments if you like and so that's
going to increase the lots this city and
it in it can have other kinds of things
and so we took took these numbers and
we made a simple theory based on stuff
other people did and the bottom line
the simple theory with them on a dispersed
liquid crystals is that in order for
this to happen that we sort of have
to have a pathologically large K.
to four OK And so.
Right now we don't understand you know so
we can understand it in the context
of that model and so we're understood
what we think is actually maybe important
which hasn't been really considered
it's hard to be quantitative about
is that you know we have a poly
dispersed distribution of links OK.
And so.
You can certainly have a situation
where there's a segregation
in this process of longer links to
the walls compared to the middle and
that would actually change the energetics
that would change the surface tension
actually if you remember it would make the
surface tension lower because it's sort of
like there's longer ones there and
then also we change the elasticities
energies in the right both of
them in the right direction so
maybe this is the origin the effect
Porton ingredient in understanding it.
That's sort of where we are OK So then
the last thing on the show you you know we
started we wanted to look at these things
so we did sort of again just really shoe.
Was critical for this we cross-link
them and we can look at them the.
And in the electron microscope these
are the structures that we showed you
pictures of you know
under the microscope so
you're going to this isn't a person's
increasing chain length and.
If you you can take these
you can actually make.
You can actually you know I don't remember
the details of the probably this is only
one sample but basically you can some
pieces we could be fibers that these
things of which many of them in parallel
Here's a sort of a mat of this stuff.
And I think.
I think that's I think
I'll stop there OK So
hopefully a different kind of a talk just
a bunch of results maybe but thank you.