What elastic polymeric material look like at molecular level?

I think there are few crosslinks in elastic material. So probably, the material would look like not so dense, maybe even transparent. 


I received this question from my collegue and have difficulty in answering it.
I think this question is about know how the structure of an elastic polymer looks on the molecular level. 


What does the elastic polymeric material look like at molecular level?




Broadly, the elastic polymeric materials are structural with the mixture of networks of molecular chains and liquid. There may be a distinction between the terms *"elastic polymeric materials"* and *"elastic polymers"*. Key features contain repetition of some parts so open to bioengineering such as bioprinting. Each specific elastic polymeric material differs at molecular level. For example some materials can have long repetitive carbon chains while some materials can have short repetitive carbon chains where each structure is attached together by some forces. There are different kinds of forces where their degree is relative to the molecule:


**Brainstorming on the question *"What look like?"* What does it mean?**


1. what is meant by "look like"?
2. intermolecular forces? Repulsive forces? Attraction forces?
3. EM fields between each charged particles? How are quantum phenomena in materials such as doping considered?
4. What does the electron current look like over the material?
5. What is the distribution of static charge?




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**Perhaps relevant**




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The book Edited by Xiang Yang Liu and Jing-Liang Li *"Soft Fibrillar Materials Fabrication and Applications"*.



> 
> *"As one of the most important classes of soft materials, supramolecular materials are of **a mixture of networks of molecular
>  chains/fibrils and a liquid. These self-assembled fibrous/ molecular
>  architectures exhibit various functionalities, ie. superhydrophobicity
>  or superior mechanical strength, etc. and consist of the controllable
>  structures.***
> 
> 
> --
> 
> 
> *The book covers the most important **soft functional materials, including small molecule physical gels, silkworm silk and spider silk
>  fibers and functional fibers**, with respect both to the fundamentals
>  and to development and engineering methods. It provides the reader
>  with the necessary knowledge on the chemical and physical formation
>  mechanisms of these materials and demonstrates that one can rationally
>  design and tune the fibrillar networks so that the resulting materials
>  exhibit the desired functionalities.*
> 
> 
> *This work is a must-have for all Materials Scientists, Polymer Chemists, Condensed Matter Physicists, and Biotechnologists working in
>  this interdisciplinary field.*"
> 
> 
> 


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The images below of vulcanized butyl rubber monomer and chains should give some clarity. Essentially elastic polymers (elastomers) consist of polymer chains that do not crystallize and are bound to each other by a cross-linking agent. 


Butyl rubber [poly(isoprene); your typical elastic material] is a good material to look at for what makes a good elastomer. As you can in **Figure 1** see the isoprene monomer has a methyl pendant group on the molecule which makes the molecue asymetric and greatly inhibits crystallization of the polymer. It also has two double bonds which you can see in **Figure 2** creates molecules which form trapezoidal monomer patterns as opposed to the typical "zig-zag." This special shape and lack of crystallization is what allows the polymer to extend a greatly as it does and spring back to it origional shape.


[![Isoprene Monomer](https://i.stack.imgur.com/b8bok.png)](https://i.stack.imgur.com/b8bok.png)


**Figure 1.** Molecular Structure of Isoprene Monomer.


[![Natural Poly(isoprene)](https://i.stack.imgur.com/RW9Rg.png)](https://i.stack.imgur.com/RW9Rg.png)
**Figure 2.** Molecular Structure of Natural Poly(isoprene).


Butyl rubber is often cross-linked with sulfur as shown in Figure 3. Note the two distinct polymer strands and the sulfur atoms linking them. This cross-linking disallows the chains from slipping by one another (like spagehtti strands being pulled with a fork) and reduces the ability of the material to permanently deform.


[![Crosslinked butyl rubber](https://i.stack.imgur.com/wmPqv.png)](https://i.stack.imgur.com/wmPqv.png)
**Figure 3.** Molecular Structure of Vulcanized Butyl Rubber


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