# Friction of polymers: from PDMS melts to PDMS elastomers

## TL;DR

This study investigates the slip behavior of PDMS polymer melts on non-adsorbing surfaces, revealing that slip length scales with viscosity and is independent of molecular weight, linking interfacial friction to monomer interactions.

## Contribution

It provides new insights into the interfacial friction mechanisms of PDMS melts and elastomers, demonstrating the proportionality of slip length to viscosity and independence from molecular weight.

## Key findings

- Slip length proportional to bulk viscosity at high shear rates
- Interfacial friction coefficient is independent of polymer molecular weight
- Direct comparison links melt and elastomer friction to monomer interactions

## Abstract

The slip behavior of polydimethylsiloxane (PDMS) polymer melts flowing on non-adsorbing surfaces made of short non-entangled PDMS chains densely end-grafted to silica has been characterized. For high enough shear rates, constant slip lengths proportional to the bulk fluid viscosity have been observed, in agreement with Navier's interfacial equation, and demonstrating that the interfacial Navier's friction coefficient is a local quantity, independent of the polymer molecular weight. Comparing the interfacial shear stresses deduced from these measured slip lengths to available friction stress measured for crosslinked PDMS elastomers, we directly compared the interfacial melt or elastomer friction coefficient to the monomer-monomer friction.