Changhong Lai,Song Wang,Pian Zhong,Yanyan Chen,Juan Xu,Xiaoli Li,Weiqiang Liu
Vascular interventional catheters are generally made of hydrophobic polymers , which may lead to vascular injury, poor lubrication and other consequences due to friction with vascular wall or stent in the process of intervention. In this study, the PDA-PVP/PEG composite coating was prepared based on common TPU catheter material to improve its hydrophilic lubrication behavior. Firstly, the oxidative self-polymerization of dopamine (PDA) was initiated and deposited on the surface of TPU in a weak alkali environment, and then the PVP/PEG coating was prepared by UV curing with PDA as the intermediate adhesion layer . The composite coating was optimized step by step by lubricating material system, process parameters, molecular weight , and concentration. Compared with the blank control group, the water contact angle decreased from 91.3° to about 28.3°, and the friction coefficient decreased from 0.4 to about 0.03, and the composite coating was not damaged after 30 min of reciprocating sliding. The results of cytotoxicity grade Level 1 and hemolysis rate less than 5 % also proved that the composite coating showed good cytotoxicity and blood compatibility. In summary, the PDA-PVP/PEG hydrophilic lubricating composite coating revealed excellent comprehensive properties.
The key to commercialization of organic‐inorganic lead halide perovskite solar cells (PSCs) is to achieve high photoelectric conversion efficiency (PCE) and long-term stability under ambient condition. In this paper, polymer mixture of polyvinylpyrrolidone (PVP) and polyethylene glycol (PEG) with appropriate mass ratio are incorporated into PbI 2 precursor solution in the preparation process of perovskite film via two-step sequential deposition method in air. The PCE of polymer mixture modified PSC based on ZnO@TiO 2 nanorod arrays is better than those of the PSC with single polymer（PVP or PEG）and the pristine one, and the PCE of 1.5 wt%PVP/0.5 wt%PEG modified device increased by 30% compared with that of the unmodified one, which is mainly a consequence of the better quality of perovskite film caused by the synergistic effect including the strong attraction between the C=O in PVP and Pb 2+ in perovskite, and the intense hydrogen bond between O atoms from PEG and H atoms in CH 3 NH 3 + . Moreover, polymer mixture modified PSC also represents better air stability compared with the device with single polymer or the pristine one，which is largely attributed to the exceptional hygroscopicity of PVP/PEG mixture, the synergistic stabilization of perovskite structure and inhibition of ion migration by the bondings between polymer mixture and perovskite. Furthermore, the mechanism of the interaction between PVP/PEG mixture and CH 3 NH 3 PbI 3 to increase the efficiency and stability of the PSC was also studied. Our work offers an effective additive to simultaneously improve the efficiency and stability of the PSCs in high humidity environment for further commercial application.
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