基于氟烷基接枝密度调控的不同抗润湿需求表面的研究

以1H, 1H, 2H, 2H-全氟癸基三乙氧基硅烷改性纳米Ti O2,通过TGA表征氟硅烷浓度与接枝密度的关系。将不同接枝密度的Ti O2颗粒分散液喷涂于玻片上,获得具有不同抗润湿性能的表面（FMTS）。利用液滴形状分析仪测定不同表面能的水、乙二醇、正十六烷、正十二烷和正癸烷在FMTS表面的接触角（Contact angle, CA）和滑动角（Sliding angle, SA）,并考察液滴撞击表面时的形态变化。结果表明：FMTS表面对液滴的黏附力随氟烷基接枝密度的增大而减弱,而抗润湿性能随接枝密度的增大而增强;当接枝密度达到2.3301、7.5871和11.3730μmol/m2时,表面分别可阻止表面能大于47.7、25.4和23.8mN/m的液体润湿。因此,利用简便的氟烷基功能化反应,可在较大范围内调控纳米Ti O2表面氟烷基的接枝密度,协同调节表面能和表面形貌,进而构建不同抗润湿需求的表面。     

晶相结构对二氧化钛氮掺杂类型及其光催化性能的影响

采用沉淀法制备不同晶型的TiO_2,采用微波法和氨气气氛焙烧法制备了氮掺杂纳米TiO_2,对其进行了XRD、XPS和UV-Vis表征,通过光催化性能的评价,考察晶型对氮掺杂TiO_2光催化活性的影响。结果表明,在TiO_2掺氮过程中,间隙氮与取代氮形式主要由制备方法决定,并不随晶型不同而变化。两种方法掺氮后对锐钛矿和金红石结构TiO_2的可见光光催化活性均有较大提高,但复合相结构的可见光光催化活性没有明显提高。     

利用有机化凹凸棒石颗粒制备W/O型Pickering乳液

选取我国储量丰富的凹凸棒石矿,对其表面进行十六烷基三甲氧基硅烷有机改性处理,将制备的纳米颗粒应用于乳液的制备。系统考察了体系pH、颗粒质量分数和油相体积分数等因素对Pickering乳液稳定性的影响。结果表明:随着分散体系pH的增加,乳液液滴尺寸先增大后减小又增大再减小;随着颗粒质量分数的提高,可用于稳定乳液的颗粒数量增多,乳液稳定性提高;随着油相体积分数的增大,乳液液滴尺寸先增大后减小又增大再减小。通过调节水相体系的pH,成功制备了由有机改性凹凸棒石颗粒单独稳定的W/O型乳液。     

纳米TiO2的有机改性及时间响应研究

以碳链依次增长的辛烷基三甲氧基硅烷、十二烷基三甲氧基硅烷和n-辛基三甲氧基硅烷对纳米TiO_2进行有机改性,随着碳链的增长,改性后纳米TiO_2的悬浮稳定性逐渐增强,润湿性可由强亲水性转变为强疏水性,固体表面能下降至稳定状态。进一步发现,改性纳米TiO_2具有一定的时间敏感性,润湿角随改性时间的变化速率具有明显的时间响应,三种改性纳米TiO_2分别存在着中时长敏感区和低时长敏感区。     

纳米二氧化硅表面接枝氮氧自由基的改性研究

采用自制的氮氧自由基改性三乙氧基硅烷,与纳米二氧化硅(SiO_2)在无水条件下进行缩合反应制得表面接枝氮氧自由基的SiO_2。采用热重分析研究了不同反应时间、反应温度以及IPTS-TEMPO用量对SiO_2表面接枝率的影响,并利用透射电镜对SiO_2表面接枝结果进行了表征。结果表明,当反应温度110℃,反应时间24 h,IPTS-TEMPO质量分数为50%时,纳米SiO_2的表面接枝率较高。改性后的SiO_2无粒子团聚现象。     

有机硅/纳米TiO_2改性丙烯酸酯乳胶涂料的研究

采用溶胶-凝胶法制备二氧化钛(TiO_2)溶胶,并用含有可聚合基团的硅烷偶联剂(KH-570)对其进行接枝改性,制备可聚合的有机硅改性纳米TiO_2溶胶,然后通过核壳乳液聚合法,制备有机硅/纳米TiO_2改性丙烯酸酯乳液,并配制乳胶涂料。研究了改性纳米TiO_2溶胶、乳化剂和引发剂的用量对乳液及乳胶膜性能的影响。结果表明:有机硅/纳米TiO_2改性乳胶膜玻璃化转变温度和热稳定性有所提高,乳胶涂料的综合性能也有所改善。     

纳米硅溶胶改性聚硅氧烷微乳液的研究

采用乙烯基三乙氧基硅烷对纳米硅溶胶进行表面改性,使其表面接枝上可反应的乙烯基官能团,以过硫酸钾作为引发剂,与乙烯基有机硅单体、丙烯酸酯类单体进行原位聚合反应制备纳米硅溶胶改性聚硅氧烷微乳液。系统研究了聚合温度、乳化剂对聚合反应过程中乳液稳定性、乳胶膜吸水率以及乳胶粒子粒径的影响,结果表明:聚合过程中反应温度分别控制在80℃、90℃,转化率最高;烷基聚氧乙烯醚(AEO)与十二烷基苯磺酸钠(LAS)质量比为1.5∶1~2∶1,乳化剂用量为1.5%~2.0%时,制备的乳液稳定性最好,乳胶膜的吸水率低于3%,与其他共混乳液、聚硅氧烷乳液相比,吸水率显著降低;透射电子显微镜(TEM)观察结果显示:乳液中存在以纳米SiO2为核、聚硅氧烷聚合物为壳的结构形态,与共混乳液相比,改性乳液中游离的纳米SiO2粒子数大大减少。     

TiO2纳米颗粒稳定的Pickering乳液用作防晒乳成分研究

采用烷基化改性的TiO_2纳米颗粒为稳定剂,化妆品级白油为油相,黄芪水溶液为水相,制备了一种载药Pickering乳液。利用TEM、接触角测试仪和光学显微镜对TiO_2纳米颗粒及载药Pickering乳液进行了表征。结果表明,该纳米颗粒分散性良好、尺寸均匀,具备良好的稳定乳液能力;通过紫外吸收测试,控制释放药物和清洗对照实验,表明该载药Pickering乳液具有较高的防晒效果和随光照时间控制释放药物以及易于从皮肤表面清洗的特性。     

两步法制备聚氨酯/纳米TiO_2共聚物及表征

采用聚氨酯与表面接枝聚丙烯酰氯的纳米TiO_2反应,实现了聚氨酯对TiO_2纳米材料的表面共价接枝。通过透射电子显微镜探测,纳米TiO_2在基体中分散良好,并对该共聚物进行了力学和热学性能的研究。DSC,FTIR的测试结果表明,通过接枝,共聚物具有更好的性能。     

氰酸酯树脂/多步接枝二氧化钛复合材料的制备

采用多步接枝工艺,对纳米TiO_2进行表面改性,制备了M系列纳米TiO_2粒子,并制备了氰酸酯树脂(CE)/M系列纳米TiO_2粒子复合材料。研究了复合材料的摩擦性能、固化性能,分析了微观形貌与性能变化之间的关联,考察了复合材料黏度对固化工艺的影响,初步得出复合材料微观形貌与性能演变之间的规律,以及复合材料性能得以改善的微观机理。结果表明:引入少量M系列TiO_2粒子(质量分数≤4%),可改善CE的固化性能及摩擦性能。表面二次乳液接枝聚甲基丙烯酸甲酯的纳米TiO_2质量分数为4%时,复合材料摩擦因数降低约43.5%,摩擦损耗降低68.1%,耐磨性能提高。     

氮钒共掺杂纳米TiO2的表面改性及其对涂料中甲醛的降解

利用硅烷偶联剂(KH570)对氮钒共掺杂纳米TiO2进行表面改性,考察了偶联剂用量、反应时间、反应温度及pH等改性条件的影响,从而确定最佳用量和最佳反应条件.利用元素分析、红外光谱、透射电子显微镜和热质等表征手段及亲油化度的测定,研究了表面改性的效果及分散状况.红外光谱表明,KH570以化学键合的方式结合在纳米TiO2的表面,并形成了有机包覆层,经测量,氮钒共掺杂纳米TiO2表面包覆的KH570的质量分数约为13.36％ ～14.99％.将改性后的氮钒共掺杂纳米TiO2以一定的比例加入到成膜物质中制成一系列的涂料样品,然后测定其甲醛含量.结果表明,甲醛的降解率可达到82.2％.与普通涂料相比,加入改性后的氮钒共掺杂的纳米TiO2的涂料具有优异的物理性能.     

Synthesis and friction properties of copper/PMMA composites by soapless emulsion polymerization

Copper (Cu)‐doped polymethylmethacrylate (PMMA) composites were prepared by soapless emulsion polymerization. In this process, copper nanoparticles were modified by sodium oleate (SOA) and the surface property of Cu nanoparticles changed from hydrophilic to hydrophobic. The hydrophobic Cu nanoparticles could not only avoid the oxidation of Cu in air but also improve the compatibility between Cu nanoparticles and PMMA. The TEM micrographs revealed that Cu nanoparticles were encapsulated in PMMA polymer microspheres. In addition, the uniform Cu/PMMA composite microspheres could be synthesized in such a soapless emulsion polymerization process. It was worth mentioning that the friction property in oil was well improved when little nanocomposites were added into the base oil, which indicated that the composites can be widely used in lubricating oil. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Elaboration of pure and doped TiO2 nanoparticles in sol–gel reactor with turbulent micromixing: Application to nanocoatings and photocatalysis

Pure and doped nanocoatings were prepared of from chemically active TiO₂ colloids. The colloids are generated in sol–gel reactor with turbulent mixing of two reactive fluids, containing titanium tetra-isopropoxide and water, in T-mixer. The particle size is measured by the light-scattering technique using optical-fibre probe. The TiO₂ nanoparticles doped with nitrogen are obtained by the injection of a doping agent into the reaction zone at the mixing stage. The mixing at the nucleation stage has a strong impact on the nanoparticles polydispersity and mean size. The prepared nanocoatings show photocatalytic activity under UV and visible light illumination.     

Toward enhancement of TiO2 surface defect sites related to photocatalytic activity via facile nitrogen doping strategy

This study examined the catalytic activities of three distinct N–Pd@TiO₂ nanoparticles, post-annealed (at 700, 800, and 900 °C) after fabrication on silicon substrates. Systematically, HRPES and SPEM indicated that nitrogen was predominantly doped around PdO nanostructure. Particularly, we prove that photocatalytic activity in effective nitrogen doped surface area is far higher than in undoped area of Pd@TiO₂ nanoparticles by measuring for oxidation reaction of benzenethiol, thioacetic acid, and thiobenzoic acid. Besides to the band gap narrowing, nitrogen doping leads to generate Ti^3 + species or oxygen vacancies site of the surface, which leads to enhance the activity of surface photocatalysis.     

Thermal and XPS studies on polyaniline salts prepared by inverted emulsion polymerization

Conductive polyaniline salts were synthesized by inverted emulsion polymerization method and were characterized by thermogravimetric analysis (TGA), thermogravimetry‐mass (TGA‐MS) analysis, and X‐ray photoelectron spectroscopy (XPS) methods. The various characteristic fragments evolved during the thermal degradation of polyaniline were identified. The weight loss of dopants as well as sodium lauryl sulfate decomposition were identified at different temperatures from TGA‐MS analysis. The kinetic analysis of the thermal decomposition processes of polyaniline in doped state was performed. Broido, Chang, and Friedman methods were used for the evaluation of kinetic parameters in nitrogen atmosphere. High resolution XPS analysis was used to provide a method of differentiating the presence of nitrogen and carbon associated in the different environments in the polyaniline base and doped‐samples. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 499–508, 2006     

基于纳米氢氧化铝颗粒的Pickering乳液制备

以异丙醇铝为原料,采用醇盐水解?水热法制备勃姆石型纳米氢氧化铝颗粒,优化制备条件;以所制颗粒为稳定剂、角鲨烯为油相,通过超声破碎法制备Pickering乳液,考察了颗粒浓度、水相成分、超声时间及功率对Pickering乳液粒径及稳定性的影响。结果表明,水热温度200℃、水热时间2 h条件下,可制得结晶度高且均一的勃姆石型纳米氢氧化铝颗粒,平均粒径为55.70?9.20 nm,多分散性指数(PDI)为0.187?0.011;所制Pickering乳液平均粒径为1870?55 nm,PDI=0.120?0.010,可在室温下稳定储存120 d以上,且生物相容性良好,有望应用于生物医药领域。     

Pilocarpine‐loaded poly(DL‐lactic‐co‐glycolic acid) nanoparticles as potential candidates for controlled drug delivery with enhanced ocular pharmacological response

The poor corneal residence time of pilocarpine, an alkaloid extracted from the leaves of the Jaborandi plant, limits its ocular application. The aim of this study was to develop, characterize, and evaluate the potential of pilocarpine entrapped by poly(DL ‐lactic‐co‐glycolic acid) (PLGA) nanoparticle carriers for ocular drug delivery. Pilocarpine‐loaded nanoparticles were prepared with a double‐emulsion (water in oil in water) method and characterized with transmission electron microscopy and X‐ray diffraction analysis. The nanoparticles exhibited an average size of 82.7 nm with an encapsulation efficiency of 57%. Stability studies showed the absence of agglomeration and constancy in the amount of drug entrapped; this indicated the solidity of these particles for long‐term use. The in vitro release studies conducted in simulated tear fluid showed the sustained release of pilocarpine. In vivo evaluation of the nanoparticles was done in a rabbit model with a miosis assay and compared to an equal dose of commercially available eye drops of pilocarpine (Pilocar drops). The in vivo miosis studies showed that the duration of miotic response increased by 40% for the nanoparticles and produced an almost 68% increase in total miotic response when compared to the eye drops. In conclusion, this study clearly demonstrated the potential of pilocarpine‐loaded PLGA nanoparticles for multiplying the therapeutic effect of ophthalmic drug delivery with enhanced bioavailability and pharmacological response. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Preparation and characterization of transparent fluorocarbon emulsion doped with antimony tin oxide and TiO2 as thermal-insulating and self-cleaning coating

A transparent thermal insulation and self-cleaning coating was prepared from a fluorocarbon emulsion doped with antimony tin oxide (ATO) and anatase TiO₂ nanoparticles. The thermal insulation and self-cleaning properties of the coating film were optimized by adjusting the amount of ATO and anatase TiO₂ nanoparticles in the fluorocarbon emulsion. The fluorocarbon coating containing 2.0 wt% ATO and 0.1 wt% TiO₂ possessed good comprehensive properties of thermal resistance, self-cleaning, weathering resistance, etc. Compared with the blank glass substrate, the mean light transmittance of the coating film only decreased by about 12% in the visible range. The temperature in the chamber covered with the coated glasses decreased 7°C lower than the common glass chamber without coating. The methyl red painted on the coating was completely faded after three days of ultraviolet irradiation, so the coating film exhibited an excellent self-cleaning property. The transparent coating with excellent thermal insulation and good self-cleaning will be developed for a potential building glass paint used for energy saving and environmental protection.     

Influence of Rare Earth Doping on the Structural and Catalytic Properties of Nanostructured Tin Oxide

Nanoparticles of tin oxide, doped with Ce and Y, were prepared using the polymeric precursor method. The structural variations of the tin oxide nanoparticles were characterized by means of nitrogen physisorption, carbon dioxide chemisorption, X-ray diffraction, and X-ray photoelectron spectroscopy. The synthesized samples, undoped and doped with the rare earths, were used to promote the ethanol steam reforming reaction. The SnO₂-based nanoparticles were shown to be active catalysts for the ethanol steam reforming. The surface properties, such as surface area, basicity/base strength distribution, and catalytic activity/selectivity, were influenced by the rare earth doping of SnO₂ and also by the annealing temperatures. Doping led to chemical and micro-structural variations at the surface of the SnO₂ particles. Changes in the catalytic properties of the samples, such as selectivity toward ethylene, may be ascribed to different dopings and annealing temperatures.