title: Therapeutic-Ultrasound-Triggered Shape Memory of a Melamine-Enhanced Poly(vinyl alcohol) Physical Hydrogel.
abstract: Therapeutic-ultrasound-triggered shape memory was demonstrated for the first time with a melamine-enhanced poly(vinyl alcohol) (PVA) physical hydrogel. The addition of a small amount of melamine (up to 1.5 wt %) in PVA results in a strong hydrogel due to the multiple H-bonding between the two constituents. A temporary shape of the hydrogel can be obtained by deformation of the hydrogel (∼65 wt % water) at room temperature, followed by fixation of the deformation by freezing/thawing the hydrogel under strain, which induces crystallization of PVA. We show that the ultrasound delivered by a commercially available device designed for the patient's pain relief could trigger the shape recovery process as a result of ultrasound-induced local heating in the hydrogel that melts the crystallized PVA cross-linking. This hydrogel is thus interesting for potential applications because it combines many desirable properties, being mechanically strong, biocompatible, and self-healable and displaying the shape memory capability triggered by a physiological stimulus.
authors.affiliation: †Département de chimie, Université de Sherbrooke, Sherbrooke, Québec J1K 2R1, Canada.|‡State Key Laboratory of Polymer Materials Engineering, Polymer Research Institute, Sichuan University, Chengdu 610065, China.
authors.forename: Guo
authors.initials: G
authors.lastname: Li
authors.affiliation: †Département de chimie, Université de Sherbrooke, Sherbrooke, Québec J1K 2R1, Canada.
authors.forename: Qiang
authors.initials: Q
authors.lastname: Yan
authors.affiliation: ‡State Key Laboratory of Polymer Materials Engineering, Polymer Research Institute, Sichuan University, Chengdu 610065, China.
authors.forename: Hesheng
authors.initials: H
authors.lastname: Xia
authors.affiliation: †Département de chimie, Université de Sherbrooke, Sherbrooke, Québec J1K 2R1, Canada.
authors.forename: Yue
authors.initials: Y
authors.lastname: Zhao
mesh_terms: D001672:Biocompatible Materials / Q000737:chemistry; D003460:Crystallization; D006801:Humans; D020136:Hydrogel, Polyethylene Glycol Dimethacrylate / Q000737:chemistry* / Q000494:pharmacology; D006860:Hydrogen Bonding; D059408:Pain Management; D011142:Polyvinyl Alcohol / Q000737:chemistry*; D014227:Triazines / Q000737:chemistry* / Q000494:pharmacology; D014867:Water / Q000737:chemistry
chemical_list: D001672:Biocompatible Materials; D014227:Triazines; D014867:Water; D020136:Hydrogel, Polyethylene Glycol Dimethacrylate; D011142:Polyvinyl Alcohol; C011907:melamine
keywords: melamine; physical hydrogel; shape memory polymer; stimulus-responsive polymer; ultrasound trigger