All Questions
Tagged with polymers thermodynamics
17
questions
1
vote
0
answers
32
views
Partition function 1D polymer chain attached to a spring
Statement of the problem:
Consider a polymer chain consisting of $N$ linked monomer units with $N\gg 1$. Every monomer can be in state $\alpha$ or $\beta$ with energies $E_\alpha$ and $E_\beta$. In ...
1
vote
0
answers
52
views
Entropy due to linearization of Freely-Jointed Chain
Say I model a polymer as a freely jointed chain in 3D with N bonds of length L each one. If I stretch the chain (initially coiled) along a 2D surface until it becomes linear (basically a 1D line of ...
- 31
0
votes
1
answer
577
views
What is the link between the meaning of excluded volume and its mathematical derivation?
When we examine real polymer chains we have to consider the interactions between single monomers. Therefore we consider a Lennard-Jones-like potential for bringing two monomers together and calculate ...
- 167
0
votes
0
answers
46
views
How to theoretically determine thermal emissivity of thin polymeric films?
Maybe someone could help with determining gray-body emissivity of thin films such as polyethylene. There is a lot of conflicting data online with some sources stating polyethylene's epsilon value as 0....
- 383
2
votes
1
answer
167
views
Linking elastic moduli to shape fluctuations
I am simulating a polymer network shaped as a sphere. I would like to compute its elastic moduli (bulk and Young's, for example) not by their shear-strain definition but by looking at the fluctuations ...
- 1,225
0
votes
1
answer
2k
views
Why do rubber bands at higher temperatures stretch more?
I did an experiment where i placed a rubber band in water at different temperatures (-15°C till 90 °C) , and then a put a constant mass on the rubber band, to see how far it would stretch.
What i ...
- 11
1
vote
2
answers
1k
views
Elasticity of rubber bands at varying temperatures
So what i read online was that when rubber bands can stretch (become more elastic) more when their at colder temperatures. How i understood is that entropy allows for the molecules to align up more ...
- 11
2
votes
1
answer
855
views
Understanding roles of energy and entropy in different polymer models
Polymers can be modeled as ideal chains and bead-springs (among other various models). However, in an ideal chain, the interactions are entirely entropic, whereas in the bead-spring model, there are ...
- 237
1
vote
1
answer
246
views
Simple model of a polymer
Let's describe a polymer as a linear chain of $N$ links which all have a bendable part. The energies of one link are $\epsilon_-$ (unbended) and $\epsilon_\wedge$ (bended). Additionally, the lengthsof ...
- 723
0
votes
1
answer
114
views
Pressurizing with nitrogen vs vacuum? [closed]
pressurizing with vacuum causes volatilization of liquid.
- 325
7
votes
1
answer
2k
views
Hindered rotation model for flexible polymers: deriving the Flory characteristic ratio
In the hindered rotation model we assumes constant bond angles $\theta$ and lengths $\ell$, with torsion angles between adjacent monomers being hindered by a potential $U(\phi_i)$. In Rubinstein's ...
- 439
4
votes
1
answer
2k
views
Flory-Huggins ternary phase diagram with a neutral component
I am searching the literature for the Flory-Huggins phase diagram with the following components : polymer, solvent, and a third component that does not interact with the other components (just entropy ...
- 151
6
votes
2
answers
387
views
Thermodynamics, chaperones: How to model polymer fragmentation?
Living polymers are well described by equilibrium statistical physics. Now I would like to consider a case were living polymers undergo fragmentation due to chaperones. I can think of a kinetic ...
- 151
3
votes
2
answers
2k
views
Entropic force in polymers
According to my textbook, the elastic force in a rubber is caused to the tendency of the polymers to return to their initial disordered state of higher entropy.
But isn't this looking at entropy on ...
- 2,770
2
votes
1
answer
491
views
liquid polymers of high molecular weight
We often see a limit of melting point as a function of polymer chain length. Polyethlyene tops at about 190C, and polyethlyene glycol saturates at only 67C no matter how long the chain is:
http://www....
- 6,531