聚电解质自组装的研究进展

正负聚电解质通过静电作用力逐层吸附,可以在固体基质表面形成聚合物薄膜.论述了聚电解质静电自组装超薄膜(PEM)的研究进展,包括PEMs的制备、表征方法和在科学领域中的应用前景,着重对PEMs制备过程中的各种影响因素,如聚电解质分子的浓度、溶液的pH值等方面进行了讨论.     

聚电解质-表面活性剂固态复合物

聚电解质与相反电荷的表面活性剂在溶液中通过分子自组装生成聚电解质－表面活性剂固态复合物（ＰＥ－Ｓｕｒｆｓ）。ＰＥ－Ｓｕｒｆｓ具有较好的热学、力学及光学性能。已在可控渗透膜、光电响应性有机薄膜及化学传感器等领域显示出很好的应用和发展前景,通过改变聚电解质与表面活性剂的结构和种类可制备具有不同结构和性能的功能材料,文中对ＰＥ－Ｓｕｒｆｓ的制备、结构与性能以及应用前景进行了概述。     

含异质元素聚碳硅烷的制备及应用研究进展

回顾了聚碳硅烷陶瓷先驱体的制备方法及其化学结构,着重对近年来几种含异质金属元素聚碳硅烷先驱体的制备、化学结构及应用的研究进展进行了综述,并提出了今后的发展方向。     

木质素基聚电解质交联薄膜的透光性和透气性

以工业碱木质素、聚乙烯醇为原料,改性制备木质素季铵盐和羧甲基化聚乙烯醇,以甲醛为交联剂制备木质素基聚电解质交联薄膜。通过单因素实验对薄膜的透光性和透气性进行研究。采用紫外-可见分光光度计、压差法分别测定薄膜的光学性能、透气性能。利用静态接触角测量仪、XRD分别对薄膜的接触角、结晶结构进行分析。研究结果表明,TLQA/CMPVA交联薄膜在紫外光区的吸光度达到最大值10,在可见光区薄膜对光的透过率不到10%,甲醛的加入有利于提高TLQA/CMPVA交联薄膜的透光率。当聚电解质溶液偏弱碱(pH值=9)性时有利于聚电解质交联薄膜对光的透过。三甲基木质素季铵盐加入后,聚电解质交联薄膜对氧气和二氧化碳的透气量均增大。交联剂甲醛降低了聚电解质交联薄膜对氧气和二氧化碳的透气性。当聚电解质溶液中性或偏碱性时,聚电解质交联薄膜的透气性减小。聚电解质交联薄膜表面亲水性大于聚电解质共混薄膜表面亲水性,聚电解质交联薄膜的耐水性大于聚电解质共混薄膜。与PVA相比,CMPVA结晶结构消失。交联作用使TLQA和CMPVA复合更紧密。为TLQA/CMPVA交联薄膜的制备及其在特殊地膜、缓释包装材料中的应用提供了理论依据。     

燃料电池用ZrO_2基电解质的研究进展

掺杂二价、三价阳离子的二氧化锆(ZrO_2)基电解质广泛应用于多种电化学装置系统中,如氧泵、氧传感器和燃料电池等。分别从结构与导电原理、制备方法、导电性能及应用4个方面综述了燃料电池用ZrO_2基电解质的研究进展。着重阐述了高温固相法、溶胶-凝胶法、化学沉淀法、燃烧合成法等在制备ZrO_2基电解质方面的最新研究成果。进一步阐述了ZrO_2基电解质在传感器、燃料电池等方面的应用。     

以MnCO3为模板的聚电解质胶囊的制备

通过沉淀反应制备MnCO3，以乙醇为添加剂成功制备出分散性好的、具有所需尺寸和很窄的粒径分布的球形MnCO3微粒。采用MnCO3粒子为模板吸附相反电荷聚电解质再除去核来制备纯净中空聚电解质胶囊。对组装到MnCO3上制备出来的中空聚电解质胶囊作了研究。结果表明：这种胶囊代表了仅含有所需物质的微米尺度的独立式的聚电解质膜。粒子表面结构决定了所制备的胶囊的形态和胶囊壁厚度。     

壳聚糖-海藻酸聚电解质复合膜 (Ⅰ)激光共聚焦扫描显微镜分析形貌

以气体致孔法制备壳聚糖(Chi)-海藻酸(Alg)聚电解质复合膜．用激光共聚焦扫描显微镜(LCSM)观测并分析复合膜的形态结构．结果表明,LCSM无需样品处理即可原位观察Chi-Alg聚电解质复合膜在不同层面上的内部形态结构,通过调整添加剂NaHCO3的用量可以得到平均孔径分布在30～165μm的复合膜．该聚电解质复合膜作为一种潜在的生物医用材料,有望与细胞、药物及活性因子结合,在组织工程皮肤领域得到应用．     

燃料电池用镓酸镧基电解质的研究进展

掺杂锶离子(Sr~(2+))、镁离子(Mg~(2+))等阳离子的镓酸镧(LaGaO_3)基电解质能广泛应用于多种电化学装置系统中。分别从结构与导电原理、制备方法、电导率及燃料电池应用4个方面综述了燃料电池用LaGaO_3基电解质的研究进展。着重阐述了高温固相法、溶胶-凝胶法、柠檬酸-硝酸盐燃烧法在制备LaGaO_3基电解质方面的最新研究成果,以及LaGaO_3基电解质作为一种优良的中温离子导体,在燃料电池中的应用。     

色素增感太阳能电池电解质的研究进展

介绍了色素增感太阳能电池基本结构及原理;综述了色素增感太阳能电池电解质的研究进展及离子液体在电解质中的应用;分析了电解质对色素增感太阳能电池的影响;展望了其应用前景.     

PMMA基凝胶聚合物电解质研究进展

综述了聚甲基丙烯酸甲酯(PMMA)基凝胶聚合物电解质(GPE)的研究进展,提出了PMMA基凝胶电解质目前主要存在的问题,着重讨论了采用共聚共混、交联和添加无机填料等对PMMA进行改性的方法,以及PMMA基GPE的三种制备方法.     

利用层层组装的方法制备有机超薄膜的研究进展

论述了聚电解质自组装膜制备过程中基底亲水处理、层层组装技术的成膜理论及膜结构,着重介绍了近年来层层组装法制备有机超薄膜的发展概况。对层层组装法制备有机超薄膜今后的研究工作提出了建议。     

Layer-by-layer self-assembled polyelectrolyte membranes for solvent dehydration by pervaporation

Polyelectrolyte composite membranes were prepared by the electrostatic layer-by-layer self-assembly of oppositely charged polyelectrolytes, and the membranes were used for dehydration of isopropanol by pervaporation. The effects of membrane preparation conditions on the separation performance of the resulting membranes were investigated. It was found that a high charge density of the polyelectrolyte was favorable to the formation of permselective membranes and that the polyelectrolyte molecules should be sufficiently larger than the pore size of the microporous substrate in order to reduce the number of polyelectrolyte depositions required to form a defect-free membrane. It has been demonstrated that using the appropriate substrate and under suitable conditions for polyelectrolyte deposition, a permselective membrane can be formed with as few as two polyelectrolyte bilayers, which is much less than those commonly used in the literature (e.g., 60–90 bilayers). At 70 °C, the polyelectrolyte composite membrane with two bilayers exhibited a flux of 1.8 kg/(m² h) and a permeate water concentration of over 98 wt.% for the dehydration of isopropanol containing 9 wt.% water, which corresponds to a separation factor of greater than 495.     

磁性石墨烯的制备初探

目的制备磁性石墨烯,实现其定向排列,为进一步制备性能良好的热界面材料提供定向导热相。方法采用聚合物包覆和层层组装技术,在石墨烯表面均匀包覆带负电荷的聚磺苯乙烯(PSS)聚电解质层,然后在静电力作用下包覆一层带正电荷的聚二烯丙基二甲基氯化铵(PDDA)聚电解质。最后,借助静电力使带负电荷的磁性Fe3O4纳米粒子在附着有PDDA层的石墨烯表面形成均匀的致密覆盖层,得到磁性石墨烯,并在外磁场作用下使磁性石墨烯进行定向排列。结果采用聚电解质层层组装技术可有效地对石墨烯进行磁性化处理;粉状石墨烯比片状石墨烯定向排列效果明显;以片状石墨烯为原材料的实验条件下,加入聚电解PSS、PDDA的量越多,磁性化效果更佳。结论通过聚电解质层层组装技术可有效地对石墨烯进行磁性化处理,并在磁场作用下实现定向排列。     

Preparation of ultrathin self-standing polyelectrolyte multilayer membranes at physiological conditions using pH-responsive film segments as sacrificial layers

A new system to obtain ultrathin self-standing polyelectrolyte multilayer membranes at physiological conditions is introduced. On the surface of a substrate, a hybrid film structure composed of two compartments, (1) a pH-responsive film segment formed via hydrogen bonds and (2) a polyelectrolyte multilayer film on top of 1, was assembled. The pH-responsive polymer multilayer segments disintegrate at a neutral pH and release self-standing polyelectrolyte multilayer films. The obtained self-supporting polyelectrolyte multilayer membranes had thicknesses of 55 to several hundred nanometers and areas of a few square centimeters, approximately. The preparation method introduced here avoids harsh release conditions and thus broadens the choice of materials that can be incorporated into the self-standing film.     

Redox-controlled molecular permeability of composite-wall microcapsules

Many smart materials in bioengineering, nanotechnology and medicine allow the storage and release of encapsulated drugs on demand at a specific location by an external stimulus. Owing to their versatility in material selection, polyelectrolyte multilayers are very promising systems in the development of microencapsulation technologies with permeation control governed by variations in the environmental conditions. Here, organometallic polyelectrolyte multilayer capsules, composed of polyanions and polycations of poly(ferrocenylsilane) (PFS), are introduced. Their preparation involved layer-by-layer self-assembly onto colloidal templates followed by core removal. PFS polyelectrolytes feature redox-active ferrocene units in the main chain. Incorporation of PFS into the capsule walls allowed us to explore the effects of a new stimulus, that is, changing the redox state, on capsule wall permeability. The permeability of these capsules could be sensitively tuned via chemical oxidation, resulting in a fast capsule expansion accompanied by a drastic permeability increase in response to a very small trigger. The substantial swelling could be suppressed by the application of an additional coating bearing common redox-inert species of poly(styrene sulfonate) (PSS(-)) and poly(allylamine hydrochloride) (PAH(+)) on the outer wall of the capsules. Hence, we obtained a unique capsule system with redox-controlled permeability and swellability with a high application potential in materials as well as in bioscience.     

聚电解质刷的研究新成果及其在造纸中的应用

聚电解质刷作为一种新的表面改性方法,已经得到了广泛的关注与研究。近年来,科研工作者在该领域中主要展开了对其内核材料、外刷材料的研发及应用领域的拓展,并取得了新的突破。阳离子球型聚电解质刷可被作为一种新型的造纸助留助滤剂,应用于造纸湿部,以提高原料的利用率。为了更好地将弱聚电解质刷应用于更多领域,应该深层次研究外界因素对其作用机理。     

壳聚糖水凝胶的制备及其在药物释放中的应用

水凝胶作为性能良好的载体,在药物的控释、组织工程等领域有着广泛的应用。壳聚糖是一类天然的带正电荷的碱性多糖,由其形成的水凝胶具有较好的生物相容性、生物降解性、抗菌和低细胞毒性,因此,壳聚糖水凝胶有着良好的生物应用前景。本文综述了壳聚糖水凝胶的制备方法(包括物理交联法和化学交联法),在物理交联法部分着重介绍了离子化合物及聚电解质分子与壳聚糖通过离子交联形成水凝胶,以及利用分子链间的疏水作用形成壳聚糖水凝胶的方法;而在化学交联法部分介绍了合成壳聚糖水凝胶的化学手段,包括交联剂、光照辐射和酶的使用。继而概述了壳聚糖水凝胶在药物缓释应用方面的研究进展,包括温度、pH值和电场响应的药物控释体系。最后展望了壳聚糖水凝胶未来的发展前景。     

Transient charge-masking effect of applied voltage on electrospinning of pure chitosan nanofibers from aqueous solutions

Abstract

The processing of a polyelectrolyte (whose functionality is derived from its ionized functional groups) into a nanofiber may improve its functionality and yield multiple functionalities. However, the electrospinning of nanofibers from polyelectrolytes is imperfect because polyelectrolytes differ considerably from neutral polymers in their rheological properties. In our study, we attempt to solve this problem by applying a voltage of opposite polarity to charges on a polyelectrolyte. The application of this ‘countervoltage’ can temporarily mask or screen a specific rheological property of the polyelectrolyte, making it behave as a neutral polymer. This approach can significantly contribute to the development of new functional nanofiber materials.     

壳聚糖/海藻酸盐微胶囊膜的物质扩散性能研究

针对微囊化细胞三维培养研究背景,以壳聚糖、海藻酸钠为微载体制备材料,采用脉冲电场液滴工艺制备海藻酸钙微球,使之与壳聚糖溶液通过聚电解质络合反应生成选择透过性微囊膜.以传统细胞培养的重要碳源葡萄糖与柠檬酸、氮源L-谷氨酸为小分子模型,以聚乙二醇为测定微囊膜截留相对分子质量的模型分子,开展微胶囊传递性能研究.结果表明,葡萄糖、柠檬酸和L-谷氨酸可以自由透过微囊膜扩散,并且柠檬酸和L-谷氨酸能通过竞争螯合Ca2+引起微囊凝胶结构解聚;采用20 mg/mL海藻酸钠溶液与5万相对分子质量、2 mg/mL壳聚糖溶液制备微胶囊,囊膜的截留相对分子质量为1 500.