Stable freestanding thin films of copolymer melts far from the glass transition

TL;DR

This study demonstrates stable freestanding thin copolymer films far from their glass transition, enabling detailed analysis of their drainage and stability mechanisms driven by structural forces.

Contribution

We report the creation of stable, long-lived freestanding copolymer films far from Tg, revealing their drainage dynamics and structural stability mechanisms.

Findings

Films remain stable for over a day at room temperature.

Stratified regions form during drainage.

Stability linked to structural forces in the melt.

Abstract

Thin polymer films have attracted attention because of both their broad range of applications and of the fundamental questions they raise regarding the dynamic response of confined polymers. These films are unstable if the temperature is above their glass transition temperature Tg. Here, we describe freestanding thin films of centimetric dimensions made of a comb copolymer melt far from its glass transition that are stable for more than a day. These long lifetimes allowed us to characterize the drainage dynamics and the thickness profile of the films. Stratified regions appear as the film drains. We have evidence that the stability, thinning dynamics and thickness profile of the films result from structural forces in the melt. Understanding the key mechanisms behind our observations may lead to new developments in polymeric thin films, foams and emulsions without the use of stabilizing agents.