Surface pattern formation induced by oscillatory loading of frontally polymerized gels

Frontal polymerization (FP) is a rapid, energy-efficient technique for the manufacturing of polymeric materials and composites. It has also emerged as a way to rapidly alter the shape of partially cured polymeric materials through mechanical deformation. The first objective of this paper is to introduce a coupled thermo-chemo-mechanical theory capable of describing within the framework of nonlinear kinematics the evolution of deformation and temperature fields during frontal polymerization of gels. At the heart of the proposed theory is the introduction of eigenstrains corresponding to the phase transformation prompted by the frontal curing process. Another objective is to introduce a novel bio-inspired oscillatory loading-induced patterning technique in which we form thermoset polymeric materials with periodic surface topography patterns by applying oscillatory uniaxial loads to partially cured gels during FP. After a detailed presentation of the experimental methodology, the theoretical predictions are compared with experimental results.