The effect of surface modification on adhesion of polymer waveguide on flexible substrate

This paper is concerned with the manufacturability of a multimode and polymeric optical waveguide integrated onto flexible substrates. Waveguide-on-flex has the potential to replace complex and costly light-turning devices in optoelectronic applications. Optical polymers are known to be inferior to conventional optical materials under environmental stresses. As light signals are propagated and confined through the definition of core-cladding interface, the light guiding structure is required to adhere well and ensure long term interfacial stability. This paper describes an on-going work with a systematic approach to gain insights into the role of chemical interaction and interfacial characteristics on the adhesion strength of polymer-to-polymer interface and their impact to optical properties. Plasma surface treatment was applied to enhance interfacial adhesion between flex and cladding. The modified flex surfaces were characterised and the interfacial formation and strength with the cladding layer were analysed.