电位控制ZnO/表面活性剂复合多层膜在固/液界面上的自组装

通过控制固/液界面电极电位的方式, 控制表面活性剂和金属离子在电极表面的自组装, 制备出了高度取向的ZnO/表面活性剂复合多层膜. 对无机层形态和结构进行了分析, 并采用X射线反射率和X射线漫散射研究了电极电位控制下ZnO/表面活性剂复合多层膜在固/液界面的自组装生长. 结果表明, 在一定电位下, 只有当表面活性剂浓度低于其饱和吸附浓度时, 采用阶跃电位沉积方式才能明显改变复合薄膜的周期厚度; 恒电位沉积方式控制电极电位时, 随着沉积电位的提高, 多层膜层状结构由一组层状相变为多组层状相, 同时层状结构的取向变差. 实验研究结果验证了电化学自组装过程是由金属离子的还原速度和表面活性剂的吸附速度二者共同控制完成的.     

全内反射荧光光谱法研究水溶性卟啉在正己烷/水界面的吸附行为

在自行组装的全内反射荧光测定装置上实现了液／液界面全内反射荧光光谱的测绘,比较了水溶性的meso-四（对磺酸基苯基）卟啉（TPPS）在正己彬水界面上与在水相中荧光性质的差异,研究了全内反射荧光强度随表面活性剂种类、浓度及溶液pH值的变化情况,探索了TPPS的界面吸附行为,着重考察了阳离子表面活性剂CTMAB对TPPS界面荧光性质的影响。结果表明,在阳离子表面活性剂存在的条件下,未质子化的TPPS能够选择性地吸附在正己烷／水界面上,静电力在TPPS界面吸附过程中应起重要作用。     

Bola型表面活性剂合成及其应用

介绍了Bola型表面活性剂独特的结构特征与性质,概述了由Bola型两亲分子在气液界面自组装形成的单分子膜及囊泡的特征。重点综述了Bola型表面活性剂的合研究进展,并对其在纳米材料、药物缓释、生物矿化、光化学修饰及抑止金属腐蚀等方面的应用作了介绍。最后对其研究前景作了展望。     

疏水缔合聚丙烯酰胺与双子表面活性剂的相互作用

制备了一种脂肪酸酯双磺酸盐型双子表面活性剂, 利用粘度法、界面张力法和原子力显微镜研究了疏水缔合聚丙烯酰胺与双子表面活性剂在溶液中的相互作用. 实验结果表明: 疏水缔合聚丙烯酰胺在溶液中能够通过自组装形成疏水微区并发展成网络结构, 疏水微区与表面活性剂在溶液中能形成混合胶束; 当一定量的表面活性剂加入时, 对疏水缔合聚丙烯酰胺的自组装起促进作用, 而过多双子表面活性剂的加入又会对聚合物分子的自组装起抑制作用, 从而显著影响疏水缔合聚丙烯酰胺的溶液性质, 随着表面活性剂浓度的增加, 聚合物溶液粘度先增加、再降低; 同时, 疏水缔合聚丙烯酰胺对双子表面活性剂的界面性能也有较大影响, 聚合物的加入使双子表面活性剂降低油/水界面张力的能力下降, 油/水界面张力达到平衡所需时间延长.     

咪唑类离子液体的研究进展

咪唑类离子液体以其独特的物理化学性质和在众多领域的巨大应用潜能而引起广泛的关注.本文结合我们的研究工作,对近期国际上关于咪唑类离子液体的气-液和液-液平衡、咪唑类离子液体的表面活性剂行为、传统表面活性剂在咪唑类离子液体中聚集体的形成、表面活性剂/水(油)/咪唑类离子液体三元体系超分子自组装体形成等方面的一些主要研究成果进行了综合评述.在此基础上,提出了进一步开展非传统表面活性剂/离子液体体系超分子自组装体及离子液体结构对聚集体形成、结构、性质影响等研究的设想.     

纳米粒子的界面自组装

近年来,随着纳米技术的发展及Pickering乳液在食品、化妆品、医药等领域中的应用,纳米粒子的界面自组装现象引起了人们的广泛关注。界面能的降低是纳米粒子液液界面自组装的主要驱动力。通过改变纳米粒子的尺寸和表面配体的化学性质,可控制纳米粒子的界面自组装行为。本文综述了不同类型纳米粒子实现界面自组装的研究工作,包括均质纳米粒子、Janus纳米粒子、棒状纳米粒子以及生物纳米粒子。最后,对纳米粒子的界面组装这一领域的可能发展做了展望。     

结构化液体的设计、构筑与应用

结构化液体是近年来基于二元流体体系,利用固体粒子液/液界面自组装和堵塞相变构筑的一类非平衡态软物质材料,兼具固体的结构稳定性和液体的流动性.然而,受限于组装基元和成型方法,制备具有精准结构的智能结构化液体及衍生功能材料仍面临挑战.我们课题组在该领域开展了大量研究工作,在发展界面调控新机制,制备液体/固体新材料,以及实现材料器件新突破等方面取得了系列创新成果.本专论从固体粒子界面自组装机制出发,重点阐述了一种利用纳米粒子和聚合物液/液界面共组装制备纳米粒子表面活性剂,进而构筑结构化液体的普适策略;总结归纳了结构化液体在响应性调控、高效精准构筑以及功能材料制备等方面的研究进展;并对该领域面临的机遇和挑战做出展望.     

扩张流变法研究表面活性剂在界面上的聚集行为

近年发展起来的界面流变测定技术在研究界面性质方面具有许多独特之处.本文结合我们的工作,总结了近年来有关该技术在表面活性剂界面聚集行为研究中的应用,讨论了扩张频率、表面活性剂浓度及疏水链长、无机盐和温度对表面扩张流变行为的影响,同时探讨了小分子表面活性剂与高分子表面活性剂表面扩张流变行为的区别以及小分子表面活性剂在气/液界面与液/液表面的扩张流变性的差异.大量研究表明,借助于界面流变性的测定不仅可以研究发生在界面上和界面附近的微观弛豫过程,而且可以探讨界面上超分子聚集体的形成,进而为乳状液和泡沫等分散体系的稳定性提供依据.     

离子液体表面活性剂在水溶液中的自组装及其调控研究进展

离子液体表面活性剂在化学合成、材料制备和环境污染控制等方面的应用与它们在水溶液中的自组装及其微观结构密切相关。因此,研究离子液体表面活性剂在水溶液中的自组装行为具有重要的意义。本文重点综述了阳离子的结构、阴离子的类型、外加电解质、有机添加剂、环境因素(温度、溶液pH值和光)等对离子液体表面活性剂在水中的自组装行为以及对组装体结构影响的研究进展,总结了这些因素对离子液体表面活性剂在水中自组装的调控规律,展望了该领域的发展方向及面临的挑战。     

介观模拟研究环境因素对油/水界面处十六烷基三甲基溴化铵自组装行为的影响

采用耗散颗粒动力学(DPD)模拟方法在介观层次上模拟了表面活性剂十六烷基三甲基溴化铵(CTAB)在油/水界面的自组装行为,考察了表面活性剂浓度、油水比例以及剪切力等环境因素对表面活性剂界面张力、尾-尾间距离及油水界面厚度的影响。结果发现,油水比例增大可显著降低CTAB存在的油水界面张力,提高CTAB的界面活性;有剪切存在时,表面活性剂在界面的聚集行为明显改变,分子在界面处的排列变得混乱,有序性降低,导致尾-尾间距离减小、界面厚度增加,界面效率显著降低。模拟表明,介观模拟方法可以作为实验的一种补充,为实验提供必要的微观分子结构信息。     

松香改性制备表面活性剂及其应用研究进展

从松香出发,可制备阴离子、阳离子、非离子和两性离子等四类表面活性剂。文章综述了国内外近年来以松香和改性松香为主要原料合成表面活性剂及其应用方面的研究进展,分别讨论了这些表面活性剂在使用过程中的主要优势和存在问题。     

Improvement of supercooling and thermal conductivity of the sodium acetate trihydrate for thermal energy storage with α-Fe<Subscript>2</Subscript>O<Subscript>3</Subscript> as addictive

In situ calorimetric technology was firstly employed to study the effects of surfactants on the materials formation. In the present study, different kinds of surfactants were selected as additives during cluster-shaped Ni-doped Fe₃O₄ synthesis. Experimental results indicate that the surfactants reduced the particle size and changed the cationic distribution, compositions and magnetic properties of the as-synthesized materials. The microcalorimetric results demonstrate that the sample formation was endothermal and divided into five processes based on the heat-flow versus time curves. No significant effects of the surfactants on these processes were found. However, the surfactants addition affected the heat flow and the temperatures for peaks in these curves. The surfactant adsorption on the crystal facet and nuclei of the sample, and the interactions among surfactants and ions contained in the system may be mainly the reason for these effects. These results demonstrate different actions of surfactants and ligands on materials formation.     

Gemini型甜菜碱表面活性剂合成进展

Gemini型甜菜碱结合了甜菜碱和Gemini型表面活性剂的优点,可以在较低浓度下达到超低油水界面张力、配伍性好、耐温耐盐性好、Krafft点以及吸附量低,被广泛应用于日用化学、化学化工、纳米材料、生物技术和石油开采等领域。本文基于间隔基的类型介绍了近年来Gemini型甜菜碱表面活性剂方面的最新研究进展。重点阐述了对称胺型、三嗪环型、二卤代物型Gemini甜菜碱的合成方法,并从原料成本、产率、反应周期以及产物的性能等方面对合成方法进行了分析和比较。最后对Gemini型甜菜碱表面活性剂的发展进行了展望。     

Ethylene Glycol as New Mobile Phase for Resolution of Two-Component Mixture of Cationic Surfactants on Alumina Surface

Aqueous ethylene glycol (ethane 1,2 diol) as a green mobile phase has been used for thin layer chromatographic (TLC) studies of cationic surfactants on alumina layers. Nineteen solvent systems were used to examine the mobility of the surfactants and to discover the best TLC system for the selective separation of dodecyl trimethylammonium bromide (DTAB) from multi-component mixture of other surfactants. Among the TLC systems studied, M₃ (ethylene glycol: water, 8:2) was best for achieving the selective separation of DTAB from multi-component mixture of other surfactants because in this mobile phase mobility of all surfactants except DTAB were insignificant. Effect of organic additives in aqueous ethylene glycol mobile phase on the mobility of surfactants was examined. The results obtained on laboratory made alumina TLC plates and commercially available precoated alumina HPTLC plates were compared. The lower limits of detection of DTAB, CPC, CTAB, HDTAC, and TTAB were 0.02, 0.05, 0.04, 0.06, or 0.08 µg per zone respectively. The resolution of mixture of cationic surfactants was also examined in the presence metal cations as an impurity in the analyzed sample.     

阴离子Gemini表面活性剂在油/水界面行为的分子动力学模拟

采用分子动力学方法研究了磺酸盐型阴离子Gemini表面活性剂在油/水界面的吸附行为, 考察了不同长度的连接基(Spacer)对表面活性剂在界面的聚集形态及界面性质的影响. 密度分布和微观结构信息显示, Gemini表面活性剂能在油/水界面形成单层膜结构. Gemini表面活性剂能使油/水界面的厚度显著增大, 并使界面形成能降低. 当连接基为6个碳时, 此类磺酸盐型Gemini表面活性剂的界面厚度最大, 形成的界面最稳定. 连接基长度对Gemini表面活性剂单层膜周围的水分子和Na⁺的吸附结构影响不大, 但是能影响水分子的扩散行为.     

Thermoresponsive polymeric nanoparticles stabilized by surfactants

Solutions of poly(N-isopropylacrylamide) (PNIPA) with ionic and nonionic surfactants were investigated by light scattering methods at temperatures 15–45 °C. In contrast to previous studies, where surfactants were used in excess, lower concentrations of surfactants were used. The formation of well-defined nanoparticles of PNIPA was observed on heating above the lower critical solution temperature. The effect of PNIPA and surfactant concentrations, and molecular weight of PNIPA on nanoparticle parameters and on the phase transition temperature of PNIPA solutions were investigated. An interpretation based on stabilization of PNIPA nuclei by surfactants was suggested.     

Fluorescence probing of albumin-surfactant interaction

Protein-surfactant interactions were studied using bovine serum albumin (BSA) and the three surfactants sodium dodecyl sulfate (SDS), cetyltrimethylammonium bromide (CTAB), and poly(oxyethylene)isooctyl phenyl ether (TX-100). The surfactants used belong to three broad classes, i.e., anionic, cationic, and nonionic. These categories of surfactants were used to elucidate the mechanism of surfactant binding to BSA, at pH 7. The interactions were followed fluorimetrically using both intrinsic tryptophan (Trp) fluorescence and the fluorescence of an external label. The aggregation behavior of the surfactants were studied in the presence of BSA. Steady-state fluorescence studies indicate that all three surfactants bind to BSA in a cooperative manner. This cooperative binding affects the binding of the external label to BSA. All these effects are also manifested in time-resolved fluorescence studies. The effects of surfactants on acrylamide quenching and energy transfer from Trp in BSA to bound dye provided valuable insights into the structural modification of BSA in presence of surfactants. The surfactant-induced conformational change of BSA was also confirmed by circular dichroism studies. However, among the three categories of surfactants, the nonionic surfactant shows the least interaction with BSA.     

Synthesis and properties of new glucocationic surfactants: model structures for marking cationic surfactants with carbohydrates

[reaction: see text] In this work, we report the synthesis of a new series of glucocationic surfactants, a class of surfactants we introduced very recently. The preparation of the surfactants is based on the synthesis of the 2-bromoethyl-2,3,4,6-tetra-O-acetyl-beta-D-glucopyranoside, whose preparation was studied in order to improve yields and stereoselectivity of this key intermediate. These glucocationic amphiphiles were prepared and studied as a model of cationic surfactants marked with a carbohydrate moiety. The use of carbohydrates as markers on cationic lipids was recently introduced to induce recognition by specific receptors, present on the surface of cell membranes. The chemicophysical characterization of these model structures can give more insight on the aggregation behavior. Conductivity and surface tension measurements were performed in order to characterize the compounds from the amphiphilic point of view. The results showed a different effect of the glucosidic moiety on the cmc value with respect to the glucopyridinium cationic surfactants. The surfactants also showed the tendency to form premicellar aggregates in solution when the hydrophobicity is raised.     

Comparative study on the interaction of DNA with three different kinds of surfactants and the formation of multilayer films

The interactions between double-stranded DNA (dsDNA) and three different kinds of surfactants, i.e., cationic, anionic, and nonionic surfactants, were investigated by cyclic voltammetry, electrochemical impedance spectroscopy and UV-vis spectroscopy. Multilayer films composed of DNA and surfactants were prepared at gold electrode by electrostatic or hydrophobic interactions. It was found that the cationic surfactant, CTAB, can bind to DNA by electrostatic interaction, and the electron transfer resistance of CTAB-DNA complex film increases first and then decreases with CTAB concentration. The anionic surfactant, LAS, can bind to DNA but by hydrophobic interaction, and the electron transfer resistance of the complex film keeps decreasing with LAS concentration. Nonionic surfactants can also directly bind to DNA by hydrophobic interaction. All the three different kinds of surfactants can form multilayer films with DNA on the electrode surface. The chemical structure of DNA keeps unchanged during interacting with these surfactants. The binding modes of DNA with these three different kinds of surfactants were also deduced.     

Synthesis and Evaluation of Ethoxylated Alkyl Sulfosuccinates as Oil Spill Dispersants

The surface properties particularly, Krafft point, foam stability and emulsion stability for the synthesized series of ethoxylated sodium monoalkyl (octyl-, dodecyl-, and cetyl-) sulfosuccinate surfactants were investigated comparing with those of sodium dioctyl sulfosuccinate. The prepared surfactants were evaluated as oil spill dispersants using screen test method. The results show that, the ethylene oxide units in the mixed moiety surfactant system (anionic–nonionic) effect on the depression of the Krafft point. Also, the increasing of ethylene oxide units in the prepared surfactants decreases the foam ability of these surfactants. The results of emulsion stability show that, the increasing in ethylene oxide units owing to the emulsion stability decreases. The prepared surfactants show a dispersion capability at different content of ethylene oxide units (9, 14, 23, and 90) and at different concentrations. The dispersion capability for these surfactants in the sea water is better than in the fresh water. The results show that, the increase of ethylene oxide units increases the dispersion efficiency of the synthesized surfactants.