Controlled synthesis of hollow calcite microspheres modulated by polyacrylic acid and sodium dodecyl sulfonate

Hollow CaCO₃ microspheres were successfully synthesized through the precipitation reaction of Na₂CO₃ with CaCl₂ in the presence of polyacrylic acid (PAA) and sodium dodecyl sulfonate (SDS) at 80 °C. The concentration of SDS is an important factor to control the synthesis of hollow CaCO₃ microspheres. X-ray diffraction confirmed that the hollow CaCO₃ microsphere consists of calcite crystals. The “pearl-necklace model” of PAA/SDS micellar aggregates serves as the spherical templates to generate hollow microspheres of CaCO₃ crystals in the precipitation system.     

Highly Stable Nickel Hexacyanoferrate Nanotubes for Electrically Switched Ion Exchange

Nickel hexacyanoferrate (NiHCF) nanotubes are fabricated by an electrokinetic method based on the distinct surface properties of porous anodic alumina. By this method, nanotubes can be formed rapidly with the morphologies faithfully replicating the nanopores in the template. The prepared nanotubes were carefully characterized using SEM and TEM. Results from IR, UV, EDX, and electrochemical measurements show that the NiHCF nanotubes exist only in the form of K₂Ni[Fe(CN)₆]. Because of this single composition and unique nanostructure, NiHCF nanotubes show excellently stable cesium‐selective ion‐exchange ability. The capacity for electrodes modified with NiHCF nanotubes after 500 potential cycles retains 95.3 % of its initial value. Even after 1500 and 3000 cycles, the NiHCF nanotubes still retain 92.2 % and 82.9 %, respectively, of their ion‐exchange capacity.     

磷酸氢钙/氨基酸共聚物生物活性复合材料

通过原位聚合法制备了磷酸氢钙/四元氨基酸共聚物(DCP/PAA)复合材料, 并采用XRD和IR方法对其组成结构进行了表征, 用模拟体液和Tris-HCl溶液分别研究了复合材料的体外生物活性和降解性能。结果表明: DCP/PAA复合材料的无机相与有机相存在着一定的相互作用; 聚合反应时间对复合材料的强度有明显的影响, 反应时间越长, PAA的黏度越大, 材料的抗压强度越高; 复合材料具有很好的生物活性, 其表面能够在模拟体液中形成磷灰石层, 新形成磷灰石的Ca与P原子比为1.59, 为缺钙磷灰石; 复合材料能够在Tris-HCl溶液中降解, PAA的黏度对复合材料在Tris-HCl中的降解有一定的影响。复合材料浸泡在Tris-HCl溶液中, 溶液的pH值在浸泡初期略有下降, 但4周后稳定在7.0~7.2, 与人体环境pH值接近。     

SiO2空心球闭孔减反膜的制备及性能研究

目的 在获得光伏/光热用SiO2减反膜高透过率的同时,提高其抗划伤性能和耐候性。方法 以聚丙烯酸（PAA, Mw~3000）为模板制备具有核壳结构的SiO2,离心水洗去除PAA模板,形成SiO2空心球,接着将空心球分散于无水乙醇中形成溶胶,然后将该溶胶与酸催化溶胶混合,形成复合溶胶,最后经浸渍提拉成膜、烧结后,在载玻片上制得SiO2空心球闭孔减反膜。用透射电子显微镜（TEM）和扫描电子显微镜（SEM）分别表征了空心球的微观结构和减反膜的表面形貌,利用紫外-可见分光光度计测试了减反膜的透过率,采用铅笔硬度测试和耐湿热测试（HAST）试验,分别检测了减反膜的抗划伤性能和耐候性。结果 TEM测试结果显示,制备的SiO2空心球结构完整,壁厚均匀。SEM图显示减反膜表面平坦。当SiO2空心球溶胶与酸催化溶胶的用量比例为9∶1时,减反膜透过率的峰值为98.1%,抗划伤硬度为5 H,经HAST试验后,其透过率为初始值的98.1%。结论 用离心水洗法去除PAA模板制备的空心球比烧结去除模板法的空心占比高,与酸催化溶胶混合后制得的SiO2空心球减反膜空隙率高、折射率低,从而其透过率得到提高。同时,减反膜闭孔结构使其表面致密平整,比开孔结构减反膜具有更高的抗划伤性能和耐候性,在户外太阳能光伏/光热玻璃表面减反方面具有重要的应用价值。     

多孔氧化铝模板结合sol-gel旋转涂敷法制备PZT纳米管

利用溶胶-凝胶旋转涂敷法在通孔的多孔阳极氧化铝(PAA)模板中制备了锆钛酸铅(PZT)纳米管,研究了溶胶浓度对样品形貌的影响。利用SEM和TEM观察了纳米管阵列和单根纳米管的形貌,采用XRD和EDS图谱分析了纳米管的相结构和化学元素组成。结果表明合成的PZT纳米管结晶良好,具有钙钛矿结构(属于四方晶系);纳米管具有较高的韧性但表面较粗糙,直径和管壁厚度分别约为75和7nm,直径与原始PAA模板的孔径相吻合。在一定范围内调节PZT溶胶的浓度(0.1～0.4mol/L),均能在PAA模板的孔洞中形成PZT多晶纳米管,且组成PZT纳米管的晶粒随着溶胶浓度的增加而变大。     

pH响应性PAA/毒死蜱/氨基化介孔硅缓释体系的制备与性能

以共缩聚法合成氨基化介孔硅,采用浸渍法制备毒死蜱/氨基化介孔硅,并以带负电荷的聚丙烯酸（PAA）为功能分子,通过静电吸附作用制备了具有pH响应的PAA/毒死蜱/氨基化介孔硅缓释体系。利用XRD、N₂吸附-脱附、TEM、SEM、TG、Zeta电位和FTIR对PAA/毒死蜱/氨基化介孔硅的结构进行了表征,并探究了其在不同pH和温度下的释药行为。结果表明,PAA通过静电作用包覆于毒死蜱/氨基化介孔硅的表面。缓释体系的药物释放主要受到PAA的阻碍作用,PAA修饰载药氨基化介孔硅显示出明显的pH响应性,当pH≤7时,其药物释放速率随pH减小而增大,而在偏碱性条件下的释药速率稍大于中性环境。同时,载药体系的释药速率还受到温度的影响。其释药行为可用Korsmeryer-Pappas动力学模型来描述。     

The chemistry of tissue adhesive materials

Each year millions of people sustain traumatic or surgical wounds, which require proper closure. Conventional closure techniques, including suturing and stapling, have many disadvantages. They inflict additional damage on the tissue, elicit inflammatory responses and have a relatively long application time. Especially for the more demanding wounds, where fluids or gasses are to be sealed off, these techniques are often insufficient. Therefore, a large variety of tissue adhesives, sealants and hemostatic agents have been developed. This review provides an overview of such tissue adhesive materials from a polymer chemistry perspective. The materials are divided into synthetic polymer, polysaccharide and protein based adhesives. Their specific properties and behavior are discussed and related to their clinical application. Though each type has its specific advantages, yet few have become standard in clinical practice. Biomimetic based adhesives and other novel products have shown promising results but also face specific problems. For now, the search for better adhering, stronger, easier applicable and cheaper adhesives continues and this review is intended as starting point and inspiration for these future research efforts to develop the next generation tissue adhesives.     

磁性壳聚糖-聚丙烯酸载药微球的释放性能研究

对合成的壳聚糖-聚丙烯酸及磁性壳聚糖-聚丙烯酸微球用扫描电镜进行形貌观察,并测定了磁性壳聚糖-聚丙烯酸微球的热稳定性。以牛血清白蛋白(BSA)为模拟蛋白药物,研究了载有BSA的磁性壳聚糖-聚丙烯酸微球的释放性能。结果表明,壳聚糖-聚丙烯酸共聚物外形呈片层状;而磁性壳聚糖-聚丙烯酸微球为致密微球,粒径约在100～400 nm之间,具有较好的分散性,磁性壳聚糖-聚丙烯酸微球在温度区间(0～135℃)内具有良好的热稳定性。载有BSA的磁性微球在模拟肠液中刚开始时有一个突释过程,之后缓慢释放,在6h左右达到了平衡,最终释放率可达到80．5%;而在模拟胃液中几乎没有释放,平衡释放率只有5．8%。     

高聚物絮凝剂在水质处理中应用的现况

论述了高聚物絮凝剂的研究开发与应用的现况,分别对聚丙烯酰胺、淀粉衍生物及甲壳素、壳聚糖类絮凝剂的制备及应用进行分析探讨.