Hydrogels for active photonics

Abstract

Conventional photonic devices exhibit static optical properties that are design-dependent, including the material’s refractive index and geometrical parameters. However, they still possess attractive optical responses for applications and are already exploited in devices across various fields. Hydrogel photonics has emerged as a promising solution in the field of active photonics by providing primarily deformable geometric parameters in response to external stimuli. Over the past few years, various studies have been undertaken to attain stimuli-responsive photonic devices with tunable optical properties. Herein, we focus on the recent advancements in hydrogel-based photonics and micro/nanofabrication techniques for hydrogels. In particular, fabrication techniques for hydrogel photonic devices are categorized into film growth, photolithography (PL), electron-beam lithography (EBL), and nanoimprint lithography (NIL). Furthermore, we provide insights into future directions and prospects for deformable hydrogel photonics, along with their potential practical applications.

An Overview of Polymeric Hydrogel Applications for Sustainable Agriculture

“…Several approaches are used in this polymerization process, including bulk, solution, suspension, and emulsion polymerization [46]. Additionally, there are non-conventional techniques for radical polymerization, like reversible additionfragmentation chain transfer polymerization (RAFT) [54] and atom transfer radical polymerization (ATRP) [55].…”