Polymerization-Induced Growth of Microprotuberance on the Photocuring Coating

Surface pattern on the nano- and microscale is of great interest due to its special optical effect, which might find potential application in optical devices such as LCD display, packaging of LED chip, and thin-film solar cell. We here developed a facile bottom-up approach to fabricate microprotuberance (MP) on surface by using curable resin via sequential photocuring at room temperature and thermal polymerization at high temperature. The curable resin is composed of random fluorinated polystyrene (PSF) as blinder and trimethylolpropane trimethacrylate (TMPTA) as cross-linker. The polymerization of TMPTA during the annealing process at high temperature induces phase separation between the PSF and TMPTA cross-linked network, resulting in the extrusion of PSF and the formation of protuberance on the surface. The formation mechanism of MP was studied in detail by investigating the effect of annealing time, temperature, thickness of film, and PSF on the size and morphology. MPs with size from one to tens of micrometers were fabricated through this one-pot strategy. Moreover, encapsulation of integrated GaN/InGaN-based LED chip by the cross-linked coating with MP can enhance the light extraction efficiency and light diffusion obviously

Multi-Responsive Wrinkling Patterns by the Photoswitchable Supramolecular Network

Multiresponsive reversible wrinkling patterns provide an effective approach to dynamically tuning the properties of surface on-demand to realize a smart surface; however, their fabrication remains challenging. In this study, we report a simple yet robust method to fabricate multiresponsive wrinkles based on a supramolecular polymer network composed of copolymer (P4VP-PS-PnBA) and carboxyl containing anthracene (AN-COOH), which can be cross-linked dynamically through reversible photodimerization of anthracene (AN) and the hydrogen bond between carboxyl and pyridine groups. The wrinkle pattern can be generated and erased selectively by UV radiation of different wavelengths due to reversible dimerization of AN. The resulting wrinkles have an extremely sensitive response to hydrogen chloride (HCl) gas and can be erased by HCl with a concentration of 5 ppm in the atmosphere. The generation/elimination process responsive to light and HCl could be cycled many times without damaging characteristic wrinkles, which enables this dynamic wrinkle pattern to be employed for such potential applications as smart displays and nonink printing

Multi-Responsive Wrinkling Patterns by the Photoswitchable Supramolecular Network

Multiresponsive reversible wrinkling patterns provide an effective approach to dynamically tuning the properties of surface on-demand to realize a smart surface; however, their fabrication remains challenging. In this study, we report a simple yet robust method to fabricate multiresponsive wrinkles based on a supramolecular polymer network composed of copolymer (P4VP-PS-PnBA) and carboxyl containing anthracene (AN-COOH), which can be cross-linked dynamically through reversible photodimerization of anthracene (AN) and the hydrogen bond between carboxyl and pyridine groups. The wrinkle pattern can be generated and erased selectively by UV radiation of different wavelengths due to reversible dimerization of AN. The resulting wrinkles have an extremely sensitive response to hydrogen chloride (HCl) gas and can be erased by HCl with a concentration of 5 ppm in the atmosphere. The generation/elimination process responsive to light and HCl could be cycled many times without damaging characteristic wrinkles, which enables this dynamic wrinkle pattern to be employed for such potential applications as smart displays and nonink printing

Simultaneous Formation of a Self-Wrinkled Surface and Silver Nanoparticles on a Functional Photocuring Coating

Bioinspired functional surface with micro/nanostructures are particularly attractive because of the potential for outstanding characteristics, such as self-cleaning, self-replenishing and antibiosis. Here, we presented a facile approach to fabricate a functional photocuring coating with both a self-wrinkling patterned surface and incorporated silver nanoparticles (Ag NPs). Fluorinated polymeric photoinitiator (FPPI) and silver precursor (TFAAg) can self-assemble together on the air/acrylate interface to form a top layer of photocuring liquid resin. Under UV irradiation, a wrinkled pattern was formed as a result of the mismatch in shrinkage caused by photopolymerization between the top layer and the bulk layer. Simultaneously, Ag NPs with sizes of 15 ± 8 nm in diameter were in situ generated in the photocuring coating through the photoreduction of TFAAg. Their number density is higher in the top layer than in the bulk. Scanning electron microscope (SEM) and atomic force microscope (AFM) measurements revealed that the characteristic wavelength (λ) and amplitude (<i>A</i>) of the wrinkled morphology increased with growing concentration of FPPI, and that the generation of Ag NPs led to the wrinkle-to-fold transition. Furthermore, the obtained functional coatings possess a low surface energy and self-replenishing and antibiosis capabilities as a result of the synergistic effect of the wrinkled surface covered by FPPI and Ag NPs