Controlled Surface Textures of Elastomeric Polyurethane Janus Particles: A Comprehensive Review.

Colloidal particle research has witnessed significant advancements in the past century, resulting in a plethora of studies, novel applications, and beneficial products. This review article presents a cost-effective and low-tech method for producing Janus elastomeric particles of varied geometries, including planar films, spherical particles, and cylindrical fibers, utilizing a single elastomeric material and easily accessible chemicals. Different surface textures are attained through strain application or solvent-induced swelling, featuring well-defined wavelengths ranging from sub-microns to millimeters and offering easy adjustability. Such versatility renders these particles potentially invaluable for medical applications, especially in bacterial adhesion studies. The coexistence of "young" regions (smooth, with a small surface area) and "old" regions (wrinkled, with a large surface area) within the same material opens up avenues for biomimetic materials endowed with additional functionalities; for example, a Janus micromanipulator where micro- or nano-sized objects are grasped and transported by an array of wrinkled particles, facilitating precise release at designated locations through wrinkle pattern adjustments. This article underscores the versatility and potential applications of Janus elastomeric particles while highlighting the intriguing prospects of biomimetic materials with controlled surface textures.