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# System prepended metadata

title: Range and mechanical properties in colloidal gels
tags: [gels, glasses]

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# Range and mechanical properties in colloidal gels

###### tags: `gels` `glasses`



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### Owners (the only one with the permission to edit the main test)

Giuseppe, Mehdi



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## Background

The goal of this project is to investigate the properties of colloidal gels, as obtained by arrested phase separation, as function of the interaction range.

### The Model 

We will use the new Frenkel model that can be found here: [Wang et al. The Lennard-Jones potential: when (not) to use it](https://sci-hub.se/10.1039/C9CP05445F). It is basically a potential of variable range with smooth force and potential cut-off. 


## Plans

### The model

We will use, details in the papers, $\mu =1$ and $\nu =1$. As a cut-off, we will use two values: $r_c =1.2$ and $r_c = 2.0$ that are used in the paper to generate two phase diagram in the VDW (the fomer) and colloidal (limit):


| $r_c =2.0$ | $r_c =1.2$ | 
| -------- | -------- | 
| ![](https://i.imgur.com/nQDXHqZ.png)      | ![](https://i.imgur.com/LySJcJR.png)



We will use a 50/50 binary mixture with diameters $\sigma_s 1.0$ and $\sigma_L =1.2$. This should avoid any crystallization. I suggest that we will use a total number density $\rho = 0.17502376$, equivalent to $\phi =0.25$. For the monodisperse case, $\rho=0.5$ is equivalent to $\phi=0.2618$.

### Quenching protocol 

TBD (see below)

## To Do
:::success
green is for finished tasks
:::
### Gel assembly and structure

We will quench from high temperature the two mixtures

* Choose carefully a target temperature $T_f$, (perhaps is worth)
* Explore different quenching rates
* NVT dynamics
* Structure Factors, $U(t)$, $P(t)$

##### OPEN QUESTIONS

*  Role of the range on the finale structure???
*  Role of the quench rate??




### Mechanical properties

This will come after we pinned down the statics.

:::success
* step finished
:::
* TBD

##### OPEN QUESTIONS

*  ?
 
## OPEN BIG QUESTIONS

*  What is the role of range in the mechanical properties of gels?
*  Brittle? Ductile?



