Questions tagged [polymers]
Polymers is concerned with the physical properties of individual macromolecules. For questions regarding bulk behavior of ensembles of polymers, the [condensed-matter] tag may be more appropriate.
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Partition function for a 1 dimensional polymer
A one-dimensional polymer (a chain), made of (N + 1) monomers, is diffusing on top of a one-dimensional lattice having a lattice constant a = 1. The i-th monomer (i = 0, 1, 2,..., N) is located at a ...
- 129
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Is a worm-like-chain purely entropic?
I consider a worm-like chain with the Hamiltonian given by:
\begin{equation}
H(L)=\frac{\kappa}{2}\int_{0}^{L}ds\left(\frac{\partial\vec{t}}{\partial s}\right)^2
\end{equation}
where $\kappa$ is the ...
- 155
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Flory Theory of the real Polymer: Why is the Gain per Monomer contribution proportional to $kT$?
In Flory Theory of the real Monomer (see for example Rubinstein / Colby Polymer Physics, p.102), we want to estimate the free enrgy of a real polymer, that doesn't admit overlaps in the monomers. To ...
- 6,763
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Expanding ensemble averages
I am reading Statistical Physics of Particles by Kardar. I am struggling with problem 12d, in chapter 2, about semi-flexible polymers in two dimensions. The problem is as follows:
Configurations of a ...
- 697
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Little's model for superconducting oxidized atactic polypropylene?
Little’s organic superconductor is illustrated by this picture , which is taken from this site, and by his words: “Consider an electron moving along the spine of such a molecule. As the electron ...
- 1,103
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Derivation of second-order derivative of harmonic potential well
For a harmonic potential well:
\begin{equation}
U(r)=\frac{1}{2}(r-R) \cdot K(r) \cdot(r-R)
\end{equation}
where $R$ is a $3N$ dimensional vector describing the stable conformation of $N$ atoms, and $...
- 121
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Derivation of probability density of isolated polymers
I am reading Introduction to Polymer Physics by Doi, and in his proof for the probability distribution for ideal polymers of length $N$ and end-to-end vector $\mathbf{R}$, he does the following:
\...
- 697
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Canonical partition function, simple model of 2D polymer
I am trying to simulate using monte-carlo method the behavior of a simple of polymer.
The model -
The polymer is made of N bars with length a , each bar can be placed in +a or -a relative to
the end ...
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Discriminate closed-chain from open-chain
I have two classes of chains: closed-chains where a random path ends near where it starts (ie. loop), and open-chains without this restriction (ie. random walk). These chains are a directed graph ...
- 121
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Having trouble understand why excluded volume effect occurs
In the book of Edwards The Theory of Polymer Dynamics, at page 24 it is given that
2.5 Excluded volume effect
In the models of polymers considered in the previous sections, the interaction among the ...
- 2,283
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Worm-like chain model integral formula derivation (Kratky-Porod model)
I am having trouble understanding the derivation of the integral formula, most papers just assume the resistance to bending is:
$$\frac{A}{2}\left|\frac{dt(s)}{ds}\right|^2.$$
I have found some ...
- 111
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Why does burning polythene bags cause shrinkage while cutting them makes no change?
I don't know why polythen bags shrink on burning. But one of my friend informed me that it shrinks because at the time of its processing, the polymer is stretched and when burnt the internal stress ...
- 8,230
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Converting order parameter to director (nematics)
If I have a differential equation for the order parameter of a uniaxial nematic, like
$\frac{\partial S_{\alpha \beta}}{\partial t} = f(S_{\alpha \beta})$,
for
$S_{\alpha \beta} = S(n_{\alpha}n_{\beta}...
- 35
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Are the breakdown voltages of silicon dioxide and silicone dioxide the same?
Silicon dioxide has a breakdown voltage of $> 10$ MV/cm [1]. However, I am unable to find any information about the breakdown voltage of silicone dioxide. Since silicone contains oxygen (and ...
- 3
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Using Persistence length to establish straightness of position data
In the following picture I am showing 3D position data for 4 different tracks just to illustrate how the tracks looks like.
As we can see that we have all kind of behaviors occurring from helical ...
