Polymer Thermophoresis by Mesoscale Simulations.

Area of Science:

• Polymer physics
• Soft matter physics
• Computational chemistry

Background:

• Thermophoresis describes particle movement in response to temperature gradients.
• Standard multiparticle collision dynamics (MPCD) simulations struggle to model polymer thermophoresis.
• Understanding polymer behavior in thermal gradients is crucial for materials science and nanotechnology.

Purpose of the Study:

• To develop and validate a modified MPCD method for simulating polymer thermophoresis.
• To investigate the influence of polymer-solvent interactions on thermophoretic behavior.
• To explore the thermophoretic response of polymers with varying chain lengths and block copolymer structures.

Main Methods:

• Mesoscopic simulations using modified multiparticle collision dynamics (MPCD).
• Introduction of explicit, tunable polymer-solvent interactions.
• Analysis of polymer movement in response to imposed temperature gradients.

Main Results:

• Purely repulsive polymer-solvent interactions induce thermophilic behavior (movement towards heat).
• Attractive polymer-solvent interactions are necessary for thermophobic behavior (movement away from heat).
• Thermophoretic mobility is independent of polymer length within the studied range.
• Block copolymer thermophoresis can be predicted by weighted linear interpolation of block mobilities.

Conclusions:

• The modified MPCD method accurately captures polymer thermophoresis, aligning with experimental observations.
• Polymer-solvent interaction potential is a key determinant of thermophoretic direction.
• The observed length independence and block copolymer behavior offer valuable insights for designing responsive polymer systems.