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Model for gelation with explicit solvent effects: structure and dynamics
Michael Plischke1, D C Vernon, Béla Joós
1Physics Department, Simon Fraser University, Burnaby, British Columbia, Canada V5A 1S6.
Summary
This study models gelation using f-functional monomers and inert solvent particles. As cross-links increase, a gel forms, exhibiting unique percolation critical exponents and diverging shear viscosity.
Area of Science:
- Polymer Science
- Materials Science
- Statistical Mechanics
Background:
- Gelation is a critical process in polymer science, forming amorphous solids from liquid precursors.
- Understanding the transition from liquid to solid requires models that capture the formation of large-scale structures.
- Existing percolation models may not fully describe the unique characteristics of gelation involving multiple components.
Purpose of the Study:
- To investigate a two-component model for gelation.
- To analyze the percolation process and its critical exponents.
- To study the behavior of shear viscosity near the gelation point.
Main Methods:
- A two-component model comprising f-functional monomers (gel) and inert particles (solvent).
- Equilibration of the system as a simple liquid.
- Gradual cross-linking of gel particles to achieve a critical cross-link density.
Main Results:
- Formation of an amorphous solid when the largest gel cluster percolates.
- Identification of novel critical exponents distinct from ordinary lattice or continuum percolation.
- Observation of shear viscosity divergence as cross-link density approaches the critical value.
Conclusions:
- The two-component gelation model provides insights into the formation of amorphous solids.
- The percolation process in this system exhibits unique critical behavior.
- Shear viscosity is a key indicator of the gelation transition, diverging as the critical point is approached.