Network Design to Multifunctional Applications in Stimuli-Activated Chromic Hydrogels

The emergence of smart materials that dynamically respond to different stimuli has grown as a result of advances in materials science and engineering. Stimuli-induced chromic hydrogels have recently been studied due to their vibrant colorations in response to various stimuli. The chromism caused by environmental stimuli, originating from structural or chemical changes within the hydrogel network, affects the optical characteristics. In the case of reversible and quick color change, such chromic hydrogels are applicable in different areas, such as contact lens devices, drug delivery, anticounterfeiting, and smart windows. After providing a fundamental overview of hydrogels, the review introduces stimuli-responsive hydrogels with a focus on chromic features. Pertinent research studies that highlight the mechanisms, materials, and performance of various types of chromic hydrogels, such as photochromic, thermochromic, solvatochromic, halochromic, magnetochromic, mechanochromic, and electrochromic systems, are reviewed in this study. The main goal of this thorough review is to offer insightful information about the functionality, design, and possible applications of chromic hydrogels in cutting-edge smart technologies.