Evaluating polythiophenes as temperature sensing materials using combinatorial inkjet printing

Abstract

Polythiophenes comprise a class of emerging materials with potential applications in the field of temperature sensing. In this article, we validate and apply an integrated blending and printing methodology to combinatorially study libraries of pristine and compositionally graded blends of polythiophenes PEDOT:PSS and P(S-EDOT) (a PEDOT-like self-doped conjugated polymer) to understand their intrinsic electrical conductivity behaviour and along with its temperature dependence on blend composition and ambient temperature. Hypothesis testing is conducted to identify optima in electrical conductivity from combinations of input material proportions intended to meet multiple requirements otherwise difficult to achieve in any single-component solution-processable material. We chose PEDOT:PSS as a commercial developed intrinsically conductive polythiophene and with it, compared a novel self-doped polythiophene P(S-EDOT) as its potential replacement or complement as a sensor material. The electrical and morphological characteristics for both polymers and their blends were investigated for use as different components of temperature sensing applications. Different error sources within the process flow were considered for statistically significant conclusions regarding the utility of different compositions for different aspects of temperature sensing.