水溶性聚合物和两亲聚合物——10.两亲聚合物PAMC_(16)S的自组装有序膜

用自组装技术在金(纯金和经阳极氧化的金)表面上获得了新型两亲聚合物PAMC_(16)S的有序膜。用接触角测试,XPS谱和电化学分析等方法对自组装膜进行了表征。根据膜表面的润湿性,金表面的自组装膜是疏水的,亲水的磺酸基团连于金表面,而疏水的碳氢链从表面伸展出。XPS实验结果支持金表面上单层膜的疏水结构。聚合物单层膜复盖的金电极起到含有针孔缺陷的阻膈型电极的作用。单层膜在法拉第反应中显示很强的吸附稳定性,说明聚合物LB膜在潜在应用中有其特有的特点。     

水溶性聚合物和两亲聚合物:14.丙烯酰胺/2-丙烯酰胺基十六烷磺酸铵无规共聚物

水溶液中用硫酸亚铁-异丙苯过氧化氢氧化还原引发体系合成了丙烯酰胺(AM)/2-丙烯酰胺基十六烷磺酸铵(AMC_(16)SNH_4)无规共聚物。用元素分析、IR、~(13)C-NMR和~1H-NMR对其进行了表征。对水溶液性质的研究结果表明,与部分水解聚丙烯酰胺相比,这种新型共聚物有着优异的耐盐性、耐温性和贮存稳定性。     

一种梳型两亲聚合物的超分子结构

利用DSC、WAXD、IR及POM等手段对梳型两亲聚合物聚(2-丙烯酰胺基十六烷磺酸)(PAMC_(16)S)的超分子结构作了研究,对其组织形式作了考察,结果表明聚合物表现出梳型聚合物典型的层状堆砌,给出了其堆砌模型,对其液晶性也作了讨论。     

水溶性聚合物和两亲聚合物18.2—丙烯酰胺基烷磺酸类两亲单体

２－丙烯酰胺基烷磺酸的溶解行为和胶体化学性质明显随烷基长短而异，由于手性碳原子的存在，与其相邻亚甲基的质子峰在ＨＮＭＲ谱上清楚地发生分裂，研究了２－丙烯酰胺基十六烷磺酸（ＡＭＣ１６Ｓ）在水／二氧六环混合溶剂中的聚合动力学和胶体化化学性质，发现聚合速度和所得聚合物分子量均均在水／二氧六环体积比为１～１／２时出现最小值，临界胶束浓度随混合溶剂中二氧六环含量的增加而增加，当水／二氧六环体积比为１／２～１     

聚合物Langmuir—Blodgett膜研究进展

聚合物LB膜可用两种方法制备,一种是两亲单体成膜再进行聚合反应,另一种为直接从两亲聚合物在亚相表面铺展成膜并转移。本文综合聚合物LB膜的研究状况,包括两亲聚合物和非两亲聚合物,对聚合物LB膜的成膜特点,结构和性能作了描述,并简要介绍了聚合物LB膜的应用前景。     

水溶性聚合物和两亲聚合物18．2－丙烯酰胺基烷磺酸类两亲单体

２－丙烯酰胺基烷磺酸的溶解行为和胶体化学性质明显随烷基长短而异。由于手性碳原子的存在，与其相邻亚甲基的质子峰在~１ＨＮＭＲ谱上清楚地发生分裂。研究了２－丙烯酰胺基十六烷磺酸（ＡＭＣ１６Ｓ）在水／二氧六环混合溶剂中的聚合动力学和胶体化学性质。发现聚合速度和所得聚合物分子量均在水／二氧六环体积比为１～１／２时出现最小值，临界胶束浓度随混合溶剂中二氧六环含量的增加而增加，当水／二氧六环体积比为１／２～１／４时，观察不到胶束化现象。     

水溶性聚合物和两亲聚合物23.两亲聚合物PAMC16S对螺(噁)嗪化学和物理行为的影响

研究了两亲聚合物聚 (2 -丙烯酰胺基十六烷磺酸 ) (PAMC16S)存在下 1 -乙基 -3 ,3 -二甲基螺 [吲哚啉 -萘并口恶嗪 ](SO -E)在水溶液中的增溶作用及PAMC16S对SO -E化学和光化学性质的影响。PAMC16S明显增加了SO -E在水相的溶解性 ,SO -E的最大增溶浓度随PAMC16S浓度增加呈线性增加规律。在PAMC16S存在下 ,新配制的SO -E溶液显示可逆的光致变色性 ,显色体呈红色 ,最大吸收峰位于 5 2 0nm ,在室温下的消色反应速度明显慢于无PAMC16S存在下的兰色显色体。SO -E/PAMC16S溶液是不稳定的 ,配制后较长时间即失去SO -E的正常光致变色性质。盐酸具有与PAMC16S相似的作用 ,SO -E/PAMC16S体系的不稳定性可用氨水中和的方法解决。1H -NMR结果表明SO -E在酸性介质中发生了不可逆的化学反应。     

亚相酸度及金属离子对2-十六氨基甲酰基-8-羟基喹啉成膜性能的影响

合成了两亲配体2-十六氨基甲酰基-8-羟基喹啉(简称HHQ),研究了亚相酸度及金属离子对HHQ成膜性能的影响。金属离子的半径、电荷及核外价电子层结构不同是影响HHQLang-muir单分子层膜性能的本质原因。从含有Ni²⁺、Cu²⁺离子的亚相表面所制备的多层LB膜的吸收光谱中产生了一个新的吸收峰。     

新显色剂1-(2-咪唑偶氮)-2-萘酚-4-磺酸作为络合滴定指示剂的研究

本文报道了新显色剂1-(2-咪唑偶氮)-2-萘酚-4-磺酸(IANS)的物理性质、酸离解常数,并对该试剂作为EDTA络合滴定Cu~(2+)、Zn~(2+)、Pb~(2+)、Cd~(2+)、和Hg~(2+)的指示剂进行了研究,结果与二甲酚橙比较令人满意。     

两亲分子溶液聚集体结构的冷冻刻饰

利用冷冻刻饰电子显微镜(FF-TEM)技术研究了两亲分子溶液不同有序聚集体的结构, 特别对一些两亲分子溶液体系形成的泡囊结构进行了详细的研究, 探讨了聚集体结构的演变规律. 对无剪切力下化学反应诱导L₃-相(海绵相)到层状Lα-相, 手振荡层状Lα-相到多双层泡囊相及高剪切力作用下多双层泡囊相到单双层泡囊相的结构演变进行了冷冻刻饰电子显微镜追踪研究. 首次报道了Zn²⁺-诱导的单链长表面活性剂溶液中泡囊相的形成.     

Formation of flat, homogeneous surfaces of organized molecular films of three-armed polymerizable amphiphiles with metal-scavenging properties

Surface complexing (i.e., metal-bridged polymerization in this study) of a three-armed amphiphilic compound with metal-scavenging properties has been investigated using the surface pressure-area (π-A) isotherms of a Langmuir monolayer from the subphase. Inductively coupled plasma mass spectrometry (ICP-MS) was also carried out on eluted solutions from corresponding multilayers of the solid. Furthermore, the molecular arrangement and surface morphology of organized molecular films of the resultant comb polymer were estimated by in-plane and out-of-plane X-ray diffraction (XRD) and by atomic force microscopy. From an analysis of the wide-angle X-ray diffraction of the corresponding monomer in the bulk, the long hydrocarbon chains are observed to pack hexagonally in the solid state. Compared to their monolayer on distilled water as the subphase, a polymerized monolayer on a buffer solution containing Cd(2+) ions is remarkably expanded at 15 °C. From ICP-MS and IR measurements, it is found that this monolayer stoichiometrically contains Cd(2+) ions on the -SH group. It is found by XRD that highly ordered layer structures and regular 2D lattices are constructed in the organized molecular films of the Cd-bridged comb polymer. Furthermore, the surface morphology of Langmuir-Blodgett films fabricated from the monolayers on a buffer solution containing Cd(2+) and Pd(2+) shows flat and smooth domains upon metal scavenging and polymerization.     

Monolayer formation of alkyl chain-containing phosphoric acid amphiphiles at the air/water (pH 5.6) interface: influence of temperature and cations

In the four studied monoalkyl phosphoric acids (n-C(12)H(25)OPO(OH)(2), MDP; n-C(14)H(29)OPO(OH)(2), MTP; n-C(16)H(33)OPO(OH)(2), MHP; and n-C(18)H(37)OPO(OH)(2)MOP), only MOP can form an insoluble monolayer at the air/water interface (pH 5.6), suggesting that the longer alkyl chain (> or =C(18)) is essential for the formation of insoluble monolayers. On the contrary, all four corresponding dialkyl phosphoric acids ((n-C(12)H(25)O)(2)PO(OH), DDP; (n-C(14)H(29)O)(2)PO(OH), DTP; (n-C(16)H(33)O)(2)PO(OH), DHP; and (n-C(18)H(37)O)(2)PO(OH) DOP) can form insoluble monolayers, with only the pi-A isotherm of DDP showing a phase transition plateau at 25 degrees C. The enhancement of the subphase temperature not only increases the plateau pressure of the DDP monolayer, but also induces the emergence of a plateau for the DTP monolayer. In contrast to the weak influence of Na(+) and K(+) (1 x 10(-4) M in the subphases, pH approximately 5.6) on the pi-A isotherm of DDP, Ca(2+), Sr(2+), and Ba(2+) (1 x 10(-4) M in the subphases, pH approximately 5.6) have an evident impact on the isotherms of DDP, and the different isotherm results indicate that DDP can recognize the three divalent cations at the air/water interface. In addition, the gaseous portion and phase transition plateaus of the isotherms of some DAPs on pure water and on subphases containing Ca(2+), Sr(2+), or Ba(2+) were well simulated by Volmer's equation of state and Vollhardt's equation, except for a small difference for gas phases around critical points. The relationship between the plateau and the net molecule area is also discussed.     

Formation of silver nanoparticles at the air-water interface mediated by a monolayer of functionalized hyperbranched molecules

Nanofibrillar micellar structures formed by the amphiphilic hyperbranched molecules within a Langmuir monolayer were utilized as matter for silver nanoparticle formation from the ion-containing water subphase. We observed that silver nanoparticles were formed within the multifunctional amphiphilic hyperbranched molecules. The diameter of nanoparticles varied from 2-4 nm and was controlled by the core dimensions and the interfibrillar free surface area. Furthermore, upon addition of potassium nitrate to the subphase, the Langmuir monolayer templated the nanoparticles' formation along the nanofibrillar structures. The suggested mechanism of nanoparticle formation involves the oxidation of primary amino groups by silver catalysis facilitated by "caging" of silver ions within surface areas dominated by multibranched cores. This system provides an example of a one-step process in which hyperbranched molecules with outer alkyl tails and compressed amine-hydroxyl cores mediated the formation of stable nanoparticles placed along/among/beneath the nanofibrillar micelles.     

Langmuir films of (alpha-amino) phosphorus amphiphiles on various ion-containing subphases

Monolayers of amphiphilic (alpha-amino)phosphonocarboxylic and (alpha-amino)phosphonic acids have been formed by adsorption at the air/water interface. The influence of both the ionic strength and the pH of the subphase on the stability and compactness of the monolayers have been studied. The stability and the compactness of the Langmuir films are enhanced by introduction of metallic ions such as Ca(2+) or Mg(2+) in the subphases. These effects are more pronounced with Ca(2+). These metal ions can form dimeric complexes with the phosphorus moieties of the surfactant polar heads and therefore bring the amphiphiles closer. For the less hydrophobic derivative, complexation with Ca(2+) or Mg(2+) is required to ensure the formation of a stable monomolecular film. For both phosphonocarboxylic and phosphonic compounds, models have been proposed to represent the complexation phenomenon at the air/water interface.     

Oligofunctional amphiphiles featuring geometric core group preorganization: synthesis and study of Langmuir and Langmuir-Blodgett films

Based on the principle of supramolecular preorganization, a new type of oligofunctional amphiphile, of which compounds 1-4 are representative structures, has been designed and synthesized. The typical feature of their structure is a highly rigid and geometrically well-defined central unit composed of ethynylene substituted aromatic spacers with different numbers of amphiphilic segment groups (also of a rigid geometric design) attached to it. The molecules form well-defined Langmuir films when spread from a solution at the air/water interface or when a 10(-4) M aqueous CaCl2 solution was used as the subphase. By analysis of the surface pressure-surface area (pi-A) isotherms, information on the packing behavior and orientation of the amphiphilic molecules depending on the molecular structure could be obtained. Morphological characterization of the dynamic process of monolayer compression at the air/water interface was carried out by Brewster angle microscopy, illustrating several phase states visualized as snap shots. Thin monolayer films produced on a 10(-4) M aqueous CaCl2 subphase can be transferred to a mica solid support by the Langmuir-Blodgett technique. Tapping mode atomic force microscopy reveals a surface topography of the monofilms composed of 1 and 3 that differ in roughness and also in the properties of elasticity, hardness and adhesive strength. X-Ray crystal structure analysis of three relevant intermediate compounds of the synthesis were successfully determined giving an indication of the potential structural features inherent in the new amphiphiles.     

Supramolecular assembly at interfaces: formation of an extended two-dimensional coordinate covalent square grid network at the air-water interface

Reaction of a Langmuir monolayer of an amphiphilic pentacyanoferrate(3+) complex with Ni(2+) ions from the subphase results in the formation of a two-dimensional iron-nickel cyanide-bridged network at the air-water interface. The network can be transferred to various supports to form monolayer or multilayer lamellar films by the Langmuir-Blodgett (LB) technique. The same network does not form from homogeneous reaction conditions. Therefore, the results demonstrate the potential utility of an interface as a structure director in the assembly of low dimensional coordinate covalent network solids. Characterization of the LB film extended networks by X-ray photoelectron spectroscopy (XPS), FT-IR spectroscopy, SQUID magnetometry, X-ray absorption fine structure (XAFS), and grazing incidence synchrotron X-ray diffraction (GIXD) revealed a face-centered square grid structure with an average domain size of 3600 A(2). Magnetic measurements indicated that the network undergoes a transition to a ferromagnetic state below a T(c) of 8 K.     

Anomalous behavior of amine oxide surfactants at the air/water interface

A commonly stated requirement for the preparation of stable Langmuir monolayers of amphiphilic molecules at an air/water interface is that the surfactant must be insoluble in the subphase solution; however, a few prior studies have reported that some soluble surfactants can, under certain conditions, be compressed. The anomalous compression of soluble amphiphiles is extremely interesting and important, as it presents the possibility of greatly increasing the number of candidate compounds suitable for Langmuir monolayer studies and Langmuir-Blodgett deposition. The aim of this work was to obtain a better understanding of the factors that determine whether monolayers of a given water-soluble surfactant can be compressed. A series of amine oxide surfactants, including a novel gemini surfactant, were studied to explore the relationship between molecular structure and behavior at the air/water interface. Amine oxides are an especially interesting class of surfactants because their self-assembly in solution and at interfaces is pH-sensitive. Surface pressure-area isotherms show that the solubility of a surfactant in the subphase solution is not, in and of itself, a useful parameter in predicting whether the monolayer is compressible. Molecular modeling calculations suggest that the tendency of molecules to self-assemble plays a much more important role than solubility in this regard. The effect of pH was also investigated. We present a hypothesis that formation of dimers or small clusters of molecules at the interface inhibits the dissolution of these species into the subphase, and as a consequence the monolayer can be compressed.     

纳米TiO2表面对Cd2+的吸附与光化学还原过程的QCM研究

用石英晶体微天平(QCM)现场技术研究了Cd2+在纳米TiO2表面的吸附与光化学还原过程.研究结果表明,Cd2+在纳米TiO2表面的吸附量受溶液的浓度、pH值和不同添加物的影响.当pH<7时, Cd2+不发生吸附;pH＝7时,Cd2+在TiO2膜上的吸附量接近于15.2 mg/g.在紫外光光照下, Cd2+不发生光化学反应,但在溶液中加入NO-3和HCO-2后, Cd2+在电极表面可发生光化学反应,分别生成了CdO·Cd(OH)2和Cd.当醇类物质加入后, QCM的频率略有下降, 但没有观察到单质Cd的生成.     

The Monolayer Behavior of Amphiphilic Polymer and Heterostructure of Polymer LB Film/CdS Clusters

In this paper we report the behavior of an amphiphilic polymer monolayer on pure water and Cd2+ subphase. This polymer was composed of hydrophilic ethylene diamine epichlorohydrin slightly crosslinked microgel and hydrophobic stearic chains, noted as ES-1. The introduction of Cd2+ ions in subphase had a marked effect on the process of the organization of the amphiphilic polymer at the air/water interface due to the association of Cd2+ ions with the hydrophilic network, which could be indicated by the pressure-area isotherms and Brewster Angle Microscopy. Ordered ES-1/Cd2+ LB multilayers were fabricated. After the multilayers reacted with H2S gas, CdS clusters were synthesized within the film, which was characterized by X-ray diffraction and UV-visible spectroscopy. Copyright 1999 Academic Press.