End-of-life indicators based on temperature switchable nanobombs

Abstract

Nano-gas generators were synthesized by encapsulating azo-components into hydrophobic polymer particles. The dispersions of azo-components were subsequently thermally decomposed and could be reacted with either hydrophilic or hydrophobic dyes, which were located in the continuous and dispersed phases, respectively. Both systems displayed an irreversible switch in color upon temperature increase, yielding a new class of thermochromic materials. The mechanism and kinetics of the reaction between the azo-component and copper(II) phthalocyanine were monitored by EPR spectroscopy. The dispersions were also spin-coated on glass substrates and a significant change of turbidity occurred upon heating due to the gas generation in the films.