Flexible Multifunctional Photonic Crystal Fibers with Shape Memory Capability for Optical Waveguides and Electrical Sensors

Abstract

Flexible multifunctional fibers have received much attention owing to their wide applications in biomedicine, smart wearable materials, tissue engineering, and sensors. However, the preparation of such flexible fibers with adaptability, multiple functions, and high performances has been a great challenge so far. In this paper, a new type of shape memory photonic crystal fibers (SMPFs) with optical and electrical functions is reported by coaxially growing Al2O3/ZnO photonic shells onto the polyester fiber surface. The resultant SMPFs exhibit tunable structural colors, anisotropic optical reflection property, and excellent mechanical robustness. Particularly, these SMPFs exhibit unique shape memory capability, which is otherwise difficult to achieve in those previous photonic fibers. Benefiting from the photonic band gap and the transparent inner core, these SMPFs show a distinct ability in guiding light into deep tissues along a special channel, enabling their application as a shape memory optical waveguide. In addition, the pyroelectric effect of ZnO allows their uses as a shape memory temperature sensor for dynamically monitoring mouth respiration, nose breathing, and infrared light in real time. This investigation provides a general platform for flexible multifunctional fibers, which is promising in deep tissue phototherapy, wearable electronics, and intelligent robotics.