Bending and Stretching Actuation of Soft Materials through Surface‐Initiated Polymerization

Abstract

A redhead: Surface‐grafted hydrophilic polymer brushes (see picture) with high molecular weight and graft density caused reversible bending and stretching of soft polymeric substrates on a macroscale. The shape change of the substrate was tuned to respond to different stimuli including humidity, temperature, and pH.

Smart Biomaterials

“…Cell technology provides a promising therapeutic modality for diabetes, hemophilia, cancer and renal failure [202][203][204]. Increased cell death has been observed with a high concentration of exposed unreacted side chains after gelation [206]. Biocompatibility, microporous structure, and minimal surface irritation within the surrounding tissues of hydrogel shave made them attractive for this application.…”

“…Aizenberg and co-workers have developed hydrogen-actuated integrated response system (HAIRS), in which soft and hard elements are combined to enable the reversible actuation of rigid surface nano-and microstructures by polymer layers [204,205]. Although smart bending has only provided microscopic actuation so far, Zou et al [206] investigated the macroscopic stimuli-responsive bending and stretching of soft plasticized poly(vinyl chloride) (pPVC) by grafting PDMAAm at a high graft density onto its surface by surfaceinitiated ATRP. 4.14a.…”

Chemically Controlled Bending of Compositionally Anisotropic Microcylinders

“…[13,14] These materials typically require specialty polymers, such as shape-memory polymers [15] or use macroscopically layered films. [16,17] In layered films, the anisotropic distribution of two polymers, or a polymer and a metal, is essential. This creates a mismatch in mechanical properties that gives rise to a defined bending.…”

Use of Flared Textile Cuffs in Fenestrated Stent–Grafts

“…The flared cuff is considered to be a new step in exploring the accessibility of fenestration grafts to frail patients having arterial anatomy that is complex [10]. The polymerization of shape memory polymers on polyester fibers offers very good potential due to their capacity for actuation [20]. Also, the possibility for reorientating branches without kinking enables better treatment of renal and other arteries.…”