Fabrication of Multilayered Emulsion Thin Films for Temperature-Responsive Functional Adhesives

Abstract

Herein, we introduce a temperature-responsive nanoemulsion film (NEF) system with spinodal decomposition for in-situ thermoset curing. The NEFs, fabricated by alternative layering of nanoemulsion drops with bacterial cellulose nanofibirils (BCFs) and polyelectrolytes through the layer-by-layer deposition, showed 32 % increase in Young’s modulus compared with those fabricated with polyelectrolytes only. We figured out such reinforcement stemmed from the presence of BCFs that form stiff but strong fibrillary layers in the NEF matrix. We observed that the BCF-reinforced NEFs showed the unprecedented spinodal decomposition behaviour; nanoemulsion drops uniformly dispersed in the NEF network readily interdiffused to produce microscale oil domains with controlled phase separation rate and oil domain size. By using the insight gained from the understanding of thin film-based microphase separation behaviours, finally, we demonstrated that the NEFs layered with epoxy resin nanoemulsions could be applied for temperature-responsive in-situ thermoset curing.