Study on preparation and adsorbability of dicationic LB film

本文研究了一系列单阳离子烷基铵盐[硬脂酰三甲基氯化铵(SAC)、二十二烷基三甲基氯化铵(DAC)、双硬脂基二甲基铵(DSAC)、三硬脂基甲基氯化铵(TSAC)]、阳离子烷基铵盐(XSAC)和伯十八胺(ODA)的阳离子LB膜的制备及其吸附性能。由于氨基具有很强的亲水性，具有长链的SAC和DAC的单分子膜倾向于溶解到亚相中，而具有两个或三个硬脂基的DSAC、TSAC和XSAC形成稳定的单分子膜。另一方面，oda在pH 10.1以上的亚相上形成了稳定的单分子膜。π-A等温线表明TSAC、XSAC和ODA单分子膜在亚水相中与MO和NO有很强的相互作用。Th…在保持阳离子性质的前提下，制备了TSAC、XSAC和ODA3种不同价态的LB膜，考察了不同价态和离子性质的LB膜的吸附特性。结果表明，阳离子LB膜对带负电荷的染料离子NO和Mo2+具有较高的吸附能力，吸附行为受LB膜中碳链的堆积和染料水溶液的pH值影响。然而，染料的吸附几乎是通过离子相互作用按化学计量比进行的。这些事实表明，阳离子LB膜将吸附其他带负电荷的吸附物，如官能化分子、分散粒子等。此外，阳离子LB膜中MO和NO的吸附状态明显不同，即MO相对于膜表面呈边向构型，而NO在XSAC LB膜中表现出典型的Lie-Flat构型。这可能是由于MO和NO在分子结构上的不同，因此，通过设计吸附分子的分子结构，提出了染料分子在膜中具有一定取向的能力。TITS研究得到的分子排列信息有望有助于理解各种吸附物质在阳离子LBGLMS上的吸附行为。这项研究也被认为有助于在LB基质中出现功能吸附的新官能团。如光致异构化、聚合等。较少

This study is concerned with the preparation and adsorbability of cationic LB films of monocationic alkylammonium salts, dicationic alkylammonium salt and alkylamine.At first, the film-forming properties of the cationic monolayers on the aqueous subphase were examined for a series of monocationic alkylammonium salts [Stearyltrimethylammonium chloride (SAC), docosyltrimethylammonium chloride (DAC), Distearyldimethylammonium (DSAC), Tristearylmethylammonium chloride (TSAC)], dicationic alkylammonium salt (XSAC) and primary octadecylamine (ODA). Owing to the strong hydrophilic property of the ammonium group, the monolayers of SAC and DAC having a long-chain tended to dissolve into the subphase, while DSAC, TSAC and XSAC having two or three stearyl chains formed the stable monolayers. On the other hand, ODA formed the stable monolayer on the subphase above pH 10.1. Theπ-A isotherm showed that the monolayers of TSAC, XSAC and ODA interacted strongly with MO and NO in the aqueous subphase.Th … More e LB films of TSAC, XSAC and ODA were fabricated with preserving the cationic property, and subsequently the adsorption characteristics of these LB films, being different in their valency as well as ionic property, were investigated. It was found that the cationic LB films showed high adsorbability for the negatively-charged dye ions such as NO and MO.The adsorption behavior was influenced by the packing of the hydrocarbon chain in the LB film and the pH value of aqueous dye solutions. Nevertheless, the adsorption of dyes occurred almost stoichiometrically by the ionic interaction. These facts imply that the cationic LB film would adsorb the other negatively-charged adsorbates, e. g., functionalized molecules, dispersed particle, etc. Moreover, distinction in the adsorbing state was obviously obscrved for MO and NO in the cationic LB films, i. e., MO took the edge-on configuration with respect to the film surface, while NO exhibited the lie-flat configuration typically in the XSAC LB film. This is probably due to the differerece in the molecular structure between MO and NO, and therefore, capability of incorpolation of dye molecules in the film with desired orientation was suggested by designing the molecular structure of adsorbate.Information on the molecular arrangement obtained in tits study is expected to be helpful for understanding the adsorption behavior of various adsorbates on the cationic LB Glms. This study is also considered to contribute to the appearance of new functionality of the functional adsorbates in the LB matrix. as be exemplified by photoinduced isomerization, polymerization and so on. Less