Interfacial Engineering Approach to Pattern Resilient Polymer Photonic Crystals with Temperature‐Responsive Optical Properties

Abstract

Abstract Planar, 1D photonic crystals (1D‐PCs) are stacks of alternating layers with different refractive indices, which can reflect specific wavelengths of light through the formation of a photonic bandgap. Typical systems for 1D‐PC fabrication possess relatively limited thermal and/or chemical stabilities and may require several steps for producing patterned features. Additionally, enabling stimuli‐responsive behaviors in 1D‐PCs are often achieved through relatively complex chemistries that might be difficult to scale‐up due to associated cost and energy consumption, presenting challenges toward their implementation in practical systems. Herein, through sequential depositions of phenolic resin (resol) and poly(vinylidene fluoride‐co‐hexafluoropropylene) (PVDF‐HFP), two low‐cost chemical reagents which are broadly used in industry, bright 1D‐PCs are prepared with high thermal and chemical stability at long exposure times. Furthermore, spatial differences in the reflectance behavior of the 1D‐PCs and thus resulted patterns are demonstrated through a simple, generalizable interfacial engineering approach that controls the surface wettability of PVDF‐HFP layer. Stimuli‐responsive behavior is imparted into the 1D‐PC system by leveraging the semicrystalline nature of PVDF‐HFP to provide on‐demand switchable light‐reflecting behaviors upon exposure to elevated temperatures. Overall, this work demonstrates a simple and efficient technique to develop 1D‐PCs with excellent stability, ease of patterning, and thermoresponsive reflectance from low‐cost precursors, potentially enabling their broader use in a wide array of nanotechnological applications.

Keywords

• chemical resistance
• crystallization
• fluoropolymers
• thermally responsive 1D photonic crystals
• thermal stability