Design And Performances Of Shape Memory Polyurethane With Bio-inspired Superwetting Properties

Wettability is an important property of material surface,which has continuously attracted considerable attention in the area of surface/interface research.Regulation of surface wettability is of great significance for developing new functions of the material.In recent years,researches in this area have mainly focused on the single wettability behavior of the surface,very few material surfaces possessing the changeable surface wettability.Additionally,although some current researches mainly focus on the controllable wettability by adjusting the chemical composition or roughness of the surface,it is rarely possible to achieve continuous reversible transition between two wettability states,let alone the surfaces with remote control.In this paper,inspired by the wetting characteristics of the microarray structure of natural organisms,a series of new surfaces with the controllable wettability has been reported.The shape memory polyurethane?SMPU?that can be controlled by temperature and near infrared light is used as the matrix.Several bionic microarray structures are prepared by the template replication method.Relying on the shape memory property of SMPU,the surface wettability can be reversibly converted by adjusting the shape of the microarray on the surface of the material.The main works are as follows:?1?Shape memory polyurethane?SMP?was synthesized through pre-polymer chain extension method,using polycaprolactone diol-400?PCL4000?,1,4-butanediol?BDO?,triethylamine,4,4?-Diphenylmethane diisocyanate?MDI?,glycerin and dimet-hylol propionic acid?DMPA?.Nano-iron tetroxide particles?Fe3O4-NPs?with photothermal conversion capability were added to the SMPU prepolymerization solution to obtain a kind of SMPU which can be deformed remotely by near infrared light.?2?Inspired by the superhydrophobic biological model of“lotus leaf”and“rose petal”,the bionic microarray SMPU superhydrophobic surface was prepared through template replication method.This surface can be reversibly transformed between the Cassie-baxter state and the Cassie impregnating state,by regulating the micro-nano structure.The experimental results shown that the surface has broad application prospects in controlling droplet transportation and liquid rewritable.?3?A porous microarray shape memory polyurethane surface was prepared,through template replication method.Different wettability surfaces can be obtained,by controlling the elongation of the surface.After it was stretched to different states,based on the shape memory properties of SMP,the shape and wettability of the surface can be recovered after simple heating.Demonstrated the wide application value in the fields of flexible wearable devices and droplet control.?4?A wettable surface which can be remotely controlled by near-infrared light was developed through template replication,based on SMPU-Fe3O4-NPs.The morphology of the surface microstructure can be adjusted by the irradiation of near infrared light,and then the wettability of the surface can be adjusted to realize the reversible conversion from the“rose petal effect”to the“lotus effect”.The introduction of photothermal conversion Fe₃O₄-NPs enhanced the remote control ability of the material.