PVDF粉体60^Co-γ，射线共辐射接枝NVP

采用60^Co-γ射线共辐射接枝聚合法,将N-乙烯基-2-吡咯烷酮（NVP）接枝到聚偏氟乙烯（PVDF）粉体上,以改善其亲水性。考察了反应过程中各种因素对接枝率（FI）G）的影响,并对接枝产物进行了表征。结果表明：通过60^Co-γ射线共辐射可有效实现NVP在PVDF粉体上的接枝。当辐射吸收剂量为40kGy,阻聚剂六水合硫酸亚铁铵浓度为3mmol／L,NVP体积分数为15％,甲醇为溶剂时,rDG达到18．6％,且接枝后PVDF粉体的亲水性明显提高。     

卤素离子对TiO2薄膜光致亲水性的影响

将卤化钾盐KX(X＝I、Br、Cl、F)分别引入至TiO₂溶胶中, 利用提拉法在载玻片上制得含有卤素离子的TiO₂-X薄膜样片, 通过测试样片紫外光照下水滴接触角的变化, 考察了不同浓度的KI以及不同卤素离子对TiO₂薄膜光致亲水性能的影响, 并通过测试光照后的亲水薄膜样片暗处放置不同时间后接触角的变化, 比较了含TiO₂-I和TiO₂-F薄膜样片亲水性能的持久性. 结果表明, 适量的KI有助于提高TiO2薄膜的光致亲水性, 当TiO₂溶胶中KI浓度为1.0×10^-5 mol•L^-1时, 其所制得TiO₂薄膜的光致亲水性最好, 继续增大KI浓度时, 薄膜的光致亲水性逐步下降, 当KI浓度达1.0×10^-2 mol•L^-1时, 其光致亲水性较纯TiO₂薄膜差；同时, 适量的KBr、KCl加入也有助于提高TiO₂薄膜的光致亲水性, 且随KI＞KBr＞KCl的顺序逐渐减弱, 但KF的加入降低了薄膜的光致亲水性；另外, 卤素离子的加入还有助于提高TiO₂薄膜亲水性能的持久性, 且KF＞KI. 分析认为, 卤素离子对TiO₂薄膜光致亲水性的影响与其给电子或捕获光致电子作用有关, 并提出了其作用模型, 而卤素离子与亲水基团(羟基)的氢键作用是使KX-TiO₂薄膜能够延长亲水性时间的原因.     

Converting Poly(Methyl Methacrylate) into a Triple-Responsive Polymer

Multiresponsive polymers that can respond to several external stimuli are promising materials for a manifold of applications. Herein, a facile method for the synthesis of triple-responsive (pH, temperature, CO₂) poly(N,N-diethylaminoethyl methacrylamide) by a post-polymerization amidation of poly(methyl methacrylate) (PMMA) is presented. Combined with trivalent counterions ([Fe(CN)₆]³⁻) both an upper and lower critical solution temperature (UCST/LCST)-type phase behavior can be realized at pH 8 and 9. PMMA and PMMA-based block copolymers are readily accessible by living anionic and controlled radical polymerization techniques, which opens access to various responsive polymer architectures based on the developed functionalization method. This method can also be applied on melt-processed bulk PMMA samples to introduce functional, responsive moieties at the PMMA surface.     

聚乙二醇对TiO2薄膜光致亲水性的促进作用

为了提高TiO₂薄膜的光致亲水性及其持久性, 将聚乙二醇(PEG)2000 引入TiO₂溶胶中, 利用提拉法在载玻片上制备出含PEG的TiO₂薄膜样品, 通过测试样品紫外光照下水滴接触角的变化, 考察不同浓度PEG对TiO₂薄膜光致亲水性能的影响; 并通过测试光照后的亲水薄膜样片暗处放置不同时间后接触角的变化, 比较含PEG的TiO₂薄膜和纯TiO₂薄膜样品的亲水持久性. 结果表明: PEG作为一种非离子型长链分子, 其适量的添加可促进TiO₂薄膜的光致亲水性及其持久性. 基于薄膜样品的傅里叶变换红外(FTIR)光谱和紫外-可见漫反射光谱(UV-Vis DRS)结果, 认为PEG作为空穴捕获剂有助于TiO₂薄膜中Ti³⁺的生成和稳定存在, 进而有助于亲水中心(表面羟基)的形成. 此研究对于TiO₂光自洁涂料的应用很有意义, 也为研究TiO₂的光激发瞬态行为提供了一个可能的简易方法.     

Water in Ionic Liquids: Correlation between Anion Hydrophilicity and Near‐Infrared Fingerprints

We show that fingerprints of the different states of water association can be clearly distinguished in the range of the first overtone of water′s symmetric O‐H stretching in the spectra of water‐saturated [EMIm]⁺‐based ionic liquids with anions of substantially different hydrophilicity, such as hydrophobic [(CF₃SO₂)₂N]^?, moderately hydrophilic [CF₃SO₃]^?, and highly hydrophilic [HSO₄]^?.     

Effect of Oxygen on Surface Properties and Drug Release Behavior of Plasma Polymer of n-Butyl Methacrylate

The effects of oxygen on the chemical structure, morphology, hydrophilicity and drug release behavior of radio-frequency plasma poly n- butyl methacrylate （PPBMA） thin film were carded out for the first time. ATR-FTIR and XPS showed that oxygen had little influence on the chemical structure and composition of PPBMAs, which did not agree with the thought that the presence of oxygen gas would increase the oxidized carbon functionalities in the plasma polymer. SEM and static contact angle measurement indicated that in case of deposition with oxygen, the smoothness and hydrophilicity of PPBMA were dramatically improved. The drug release behavior showed that drug release from the PPBMA coating without oxygen was biphasic patterns, while from PPBMA coating with oxygen was Higuchi release. These results were helpful for the design and tailoring of the PPBMA polymer film and other of plasma polymers film, but could provide a new idea for the drug release controlled form.     

Novel polymer monolith prepared from a water‐soluble crosslinking agent

In this study, we described the fundamental properties of novel polymer monoliths that were prepared from a water‐soluble crosslinking agent. Each monolith was evaluated by scanning electron microscope (SEM) and scanning probe microscope (SPM) to observe the monolithic structure, and the polymer films that were prepared from several monomers were evaluated by the contact angle of water. As results of evaluations, the polymer prepared from a water‐soluble crosslinking agent had high hydrophilicity. Furthermore, SEM evaluations suggested that polymer porogenic solvent (PEG) was contributed to the construction of monolithic structure, and the polymerization degree of PEG was also taken effect of the structural changing by the variation of phase separation. Additionally, the results of SPM evaluations and the differences of monolithic structure were also reflected under water condition although the swelling of polymer was observed. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 3811–3817, 2007     

Enhanced photo-induced hydrophilicity of the sol-gel-derived ZnO thin films by Na-doping

Na-doped ZnO thin films with different Na/Zn ratio were prepared by sol-gel method. The microstructure, chemical composition, surface morphology, and wettability of the thin films were investigated by X-ray diffraction, X-ray photoelectron spectroscopy (XPS), scanning electron microscopy, and water contact angle apparatus. The relation of wettability and Na/Zn ratio has been studied in detail. The wetting behavior of the thin films can be reversibly switched from hydrophobic to hydrophilic, through alternation of UV illumination and dark storage (or thermal treatment). Photo-induced hydrophilicity of the thin films increases with increasing Na/Zn ratio up to 0.08 and then decreases. The mechanism can be attributed to surface nanostructure and the concentration of Na doping.     

Preparation of Polycaprolactone Tissue Engineering Scaffolds by Improved Solvent Casting/Particulate Leaching Method

The classic solvent casting/particulate leaching method to fabricate PCL scaffolds was improved by using a centrifugal technology, a direct bonding process in preparing salt matrices and a technology of vacuum treatment under heating in the desolvation process. Series operations of preshaping, centrifuging, casting and desolvating were employed during the scaffold's manufacture. The scaffold's properties were characterized including micro‐structures, pore dimensions, porosity and hydrophilicity. The results show that centrifugal technology can improve the pore uniformity of scaffolds. In the bonding process, well‐interconnected porous structures were formed if water content was between 2～7%. The distribution of pore dimensions was from 10 to 80 μm, and the porosities were about 89%. Generally, the porosities formed by vacuum treatment at high temperature are greater than those formed by vacuum treatment at ambient temperature in the desolvation process. The fabricated porous PCL scaffolds with good elasticity and desired thickness could be a good choice for application in soft tissue engineering.     

A Novel Hydrophilic Modification of PTFE Membranes Using In Situ Deposited PANI

A new kind of polyaniline/polytetrafluoroethylene (PANI/PTFE) composite membrane has been successfully prepared by in situ deposition of PANI onto PTFE membranes during the aniline's dispersion polymerization. The PTFE membrane was plasma treated before the aniline polymerization; the induced alteration of morphology and surface properties accelerated the polymerization of aniline and increased the number density of the deposited PANI onto the PTFE surface. The surface properties and morphology of the membranes were characterized. The composite PANI/PTFE membrane exhibited an enhanced flux in salt water separation, which is up to 75% higher than the pristine membrane.