title: Programmable Shape Recovery Process of Water-Responsive Shape-Memory Poly(vinyl alcohol) by Wettability Contrast Strategy.
abstract: Water-responsive shape-memory polymers (SMPs) are desirable for biomedical applications, but their limited shape recovery process is problematic. Herein, we demonstrate a shape-memory poly(vinyl alcohol) (SM-PVA) with programmable multistep shape recovery processes in water via a wettability contrast strategy. A hexamethyldisilazane (HMDS)-treated SiO2nanoparticle layer with varying loading weights was rationally deposited onto the surface of SM-PVA, aiming to create surface-wettability contrast. The varying wettability led to different water adsorption behaviors of SM-PVA that could be well-described by the pseudo-first-order kinetic model. The results calculated from the kinetic model showed that both the pseudo-first order-adsorption rate constant and the saturated water absorption of SM-PVA demonstrated a declining trend as the loading weight of SiO2increased, which laid the foundation for the local regulation of the water-responsive rate of SM-PVA. Finally, two proof-of-concept drug-delivery devices with diverse three-dimensional structures and actuations are presented based on the water-responsive SM-PVA with preprogrammed multistep shape recovery processes. We believe the programmable shape-memory behavior of water-responsive SM-PVA could highly extend its use in drug delivery, tissue engineering scaffolds, and smart implantable devices, etc.
authors.affiliation: State Key Laboratory of Pulp and Paper Engineering, South China University of Technology , Guangzhou 510640, China.|Institute of Polymer Optoelectronic Materials & Devices, State Key Laboratory of Luminescent Materials & Devices, South China University of Technology , Guangzhou 510640, China.
authors.forename: Zhiqiang
authors.identifier: http://orcid.org/0000-0002-0844-7507
authors.initials: Z
authors.lastname: Fang
authors.affiliation: State Key Laboratory of Pulp and Paper Engineering, South China University of Technology , Guangzhou 510640, China.
authors.forename: Yudi
authors.identifier: http://orcid.org/0000-0002-7072-0797
authors.initials: Y
authors.lastname: Kuang
authors.affiliation: State Key Laboratory of Pulp and Paper Engineering, South China University of Technology , Guangzhou 510640, China.
authors.forename: Panpan
authors.initials: P
authors.lastname: Zhou
authors.affiliation: State Key Laboratory of Pulp and Paper Engineering, South China University of Technology , Guangzhou 510640, China.
authors.forename: Siyi
authors.initials: S
authors.lastname: Ming
authors.affiliation: State Key Laboratory of Pulp and Paper Engineering, South China University of Technology , Guangzhou 510640, China.
authors.forename: Penghui
authors.initials: P
authors.lastname: Zhu
authors.affiliation: State Key Laboratory of Pulp and Paper Engineering, South China University of Technology , Guangzhou 510640, China.
authors.forename: Yu
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Institute of Polymer Optoelectronic Materials & Devices, State Key Laboratory of Luminescent Materials & Devices, South China University of Technology , Guangzhou 510640, China.
authors.forename: Honglong
authors.identifier: http://orcid.org/0000-0001-9518-5738
authors.initials: H
authors.lastname: Ning
authors.affiliation: State Key Laboratory of Pulp and Paper Engineering, South China University of Technology , Guangzhou 510640, China.
authors.forename: Gang
authors.initials: G
authors.lastname: Chen
keywords: shape recovery process; shape-memory polymer; smart materials; water-responsive; wettability contrast