Issue 48, 2017

Monomer diffusion into static and evolving polymer networks during frontal photopolymerisation

Abstract

Frontal photopolymerisation (FPP) is a directional solidification process that converts monomer-rich liquid into crosslinked polymer solid by light exposure and finds applications ranging from lithography to 3D printing. Inherent to this process is the creation of an evolving polymer network that is exposed to a monomer bath. A combined theoretical and experimental investigation is performed to determine the conditions under which monomer from this bath can diffuse into the propagating polymer network and cause it to swell. First, the growth and swelling processes are decoupled by immersing pre-made polymer networks into monomer baths held at various temperatures. The experimental measurements of the network thickness are found to be in good agreement with theoretical predictions obtained from a nonlinear poroelastic model. FPP propagation experiments are then carried out under conditions that lead to swelling. Unexpectedly, for a fixed exposure time, swelling is found to increase with incident light intensity. The experimental data is well described by a novel FPP model accounting for mass transport and the mechanical response of the polymer network, providing key insights into how monomer diffusion affects the conversion profile of the polymer solid and the stresses that are generated during its growth. The predictive capability of the model will enable the fabrication of gradient materials with tuned mechanical properties and controlled stress development.

Graphical abstract: Monomer diffusion into static and evolving polymer networks during frontal photopolymerisation

Supplementary files

Article information

Article type
Paper
Submitted
29 Jun 2017
Accepted
13 Oct 2017
First published
29 Nov 2017
This article is Open Access
Creative Commons BY license

Soft Matter, 2017,13, 9199-9210

Monomer diffusion into static and evolving polymer networks during frontal photopolymerisation

M. G. Hennessy, A. Vitale, O. K. Matar and J. T. Cabral, Soft Matter, 2017, 13, 9199 DOI: 10.1039/C7SM01279A

This article is licensed under a Creative Commons Attribution 3.0 Unported Licence. You can use material from this article in other publications without requesting further permissions from the RSC, provided that the correct acknowledgement is given.

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