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Realizing smart surfaces with switchable wettability inspired by nature continues to be fascinating as well as challenging. Herein, we present a versatile dip-coating approach to fabricate smart polymer-functionalized flexible surfaces with photoswitchable superwettability. Decorated with novel acrylate copolymers bearing a trifluoromethyl side chain and fluorine-containing azobenzene derivative moieties, the modified cotton fabric possesses a rose petal-like superhydrophobicity with contact angles larger than 150°and high water adhesion. This smart surface exhibits rapid phototriggered wettability transformation between superhydrophobicity and superhydrophilicity via alternate irradiation with ultraviolet and visible light, respectively. Meanwhile, the as-prepared flexible smart surfaces have excellent chemical and physical stabilities, which could tolerate harsh environmental conditions and repetitive mechanical deformation (e.g., stretching, curling, folding, and twisting) as well as multiple washing. More importantly, based on the excellent photocontrollability, various erasable and rewritable patterns with distinct wetting properties upon selective photoirradiation can be obtained. This simple strategy and the developed smart surface may find more advanced potential applications in controllable liquid transport, patterning droplet microarrays, and microfluidic devices.

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A series of poly(dodecafluoroheptyl methacrylate)-b-poly(methyl methacrylate) (PDFMA-b-PMMA) diblock copolymer nanoparticles were prepared by reversible addition-fragmentation chain transfer (RAFT) dispersion polymerization of methyl methacrylate (MMA) in supercritical carbon dioxide. Nuclear Magnetic Resonance (NMR) and gel permeation chromatography (GPC) analysis confirmed an efficient and wellcontrolled block copolymerization. As the length of the PMMA block grows from the soluble PDFMA block it eventually becomes insoluble, which drives in situ polymerization-induced self-assembly (PISA). The influences of the length of CO 2 -philic PDFMA block, CO 2 -phobic PMMA block and polymerization pressure were investigated in this PISA process. Also spherical nano-objects were formed upon the synthesis of amphiphilic diblock copolymers in situ. It appeared that, as the length of CO 2 -philic block PDFMA was increased, there was a corresponding decrease in particle size and particle size polydispersity. Scanning electron microscope (SEM) images revealed that, during the microspheres formation, the greater degree of polymerization (DP) of MMA favoured well-controlled monodisperse microspheres. a Reactions performed with [MMA] ¼ 0.8 M, [PDFMA-CDB] : [AIBN] ¼ 2 : 1, in 50 ml high-pressure autoclave at 70 C and 30 MPa for 24 h. b M n,th ¼ (([MMA] 0 )/[PDFMA-CDB] 0 ) Â M MMA + M PDFMA-CDB . c Gel permeation chromatography (GPC) in tetrahydrofuran with PS standards. dThe degree of polymerization (DP) for each polymer was calculated by the GPC. The degree of polymerization of the second block PMMA, DP nPMMA were determined by using the following formula: DP n ¼ [(M n of diblock copolymer PDFMA-b-PMMA À M n,NMR of PDFMA-CDB)/molecular weight of MMA monomer]. e Based on the visual observations made immediately aer the recovery of the polymers from the reactor, SB ¼ solid block, WP ¼ white powder. f D n ¼ particle size. g D w /D n ¼ size distribution. n.a.: not applicable. This journal is