High dielectric constant UV curable polyurethane acrylate/indium tin oxide composites for capacitive sensing

Abstract Taking into consideration environmental issues and additive manufacturing technologies, the development of advanced UV curable polymers and polymer composites is an area of increasing interest. In this scope, polyurethane acrylate (PUA) composites with Indium Tin Oxide (ITO) were produced in order to tune morphology, optical, thermal, mechanical and dielectric properties. It is shown that ITO particles are well dispersed within the polymer matrix and that the polymerization rate and the UV curing conversion degree are influenced by the ITO content. Moreover, the optical transparency has decrease to 20% for the samples containing 10 wt% ITO content and the elastic modulus increases 10% for same sample. On the other hand, the glass transition temperature of PUA is independent of the ITO amount. ITO/PUA composites with 25 wt% ITO filler content presents high dielectric constant of 33. This composite has been used for developing a capacitive sensor, showing the suitability of the UV curable materials for capacitive sensing applications.