# Influence of grafting on the glass transition temperature of PS thin films

## TL;DR

This study investigates how the interaction between polystyrene thin films and substrates affects their glass transition temperature, finding minimal impact from grafted layers due to limitations in grafting density.

## Contribution

It demonstrates that grafted polystyrene layers do not significantly alter Tg of thin films, challenging assumptions about substrate interactions influencing glass transition.

## Key findings

- Grafting density limits influence on Tg.
- No significant Tg change with different grafted layers.
- Substrate interaction effects are minimal.

## Abstract

We present an investigation of the effect of the interaction between a thin polystyrene film and its supporting substrate on its glass transition temperature (Tg). We modulate this interaction by depositing the film on end-tethered polystyrene grafted layers of controlled molecular parameters. By comparing Tg measurements versus film thickness for films deposited on different grafted layers and films deposited directly on a silicon substrate, we can conclude that there is no important effect of the film-subtrate interaction. Our interpretation of these results is that local orientation and dynamic effects substantial enough to influence Tg cannot readily be obtained by grafting prepolymerized chains to a surface, due to intrinsic limitation of the surface grafting density.