Reversible Self‐Coiling of Microfibers with Tailored Surfaces via Elastocapillarity

Coiled microfibers, ubiquitous in nature, serve as critical building blocks with capabilities including stimuli responsiveness, mechanical reinforcement, and protective functions. Despite their potential, replicating nature's control over microfiber coiling has remained a challenge, particularly when attempting to achieve reversible coiling. In this study, polydimethylsiloxane (PDMS) network microfibers are produced and reactive ion etching (RIE) is employed to induce a differential interfacial energy that drives spontaneous self‐coiling in fluidic environments. This approach harnesses elastocapillarity to control microfiber coiling through tailored adjustments of RIE treatment and fluid surface tension. This coiling mechanism is employed to reversibly wrap and unwrap poly(methyl methacrylate) (PMMA) microspheres, highlighting potential paths for future applications in fields ranging from sensors to soft robotics.