聚甲基丙烯酸甲酯Langmuir—Blodgett复合膜及其在光电导体中…

制备了聚甲基丙烯酸甲酯（ＰＭＭＡ）ＬＢ复合膜，将其作为阻挡层首次应用于机能分离型光电导体领域。从π－Ａ曲线发现ＰＭＭＡ单分子膜具有表面压力的各向异性和松弛特性。ＴＥＭ照片显示，ＰＭＭＡ分子链在复合膜中有序排列。转移比、ＵＶ和ＸＰＳ研究表明，复合膜沉积均匀。以ＰＭＭＡ－ＬＢ复合膜作为阻挡层的光电导体表面充电电位Ｖ０＝１５１８Ｖ，光照１ｓ后的光衰百分率△Ｖ１ｓ＝５０．１６％，半衰期ｔ１／２＝０．９３ｓ     

LB型Q态CdS复合膜构象有序性研究

报道了在较高膜压及高沉积速度下硬脂镉ＬＢ膜与Ｈ２Ｓ反应制备纳米有序的机分子／ＣｄＳ纳米粒子复合膜,该膜反应后仍能保持良好的－ＣＨ２－全反式排列,即形成纵向有机－无机复合超晶格材料。     

可生物降解聚合物乙肝疫苗微球的制备和表征

采用双乳液体系（Ｗ１／Ｏ／Ｗ２）溶剂抽提法制备了聚－ＤＬ－乳酸－聚乙二醇嵌段共聚物（Ｐｏｌｙ－ｄｌｌａｃｔｉｄｅ－ｂ－ｐｏｌｙｅｔｈｙｌｅｎｅ ｇｌｙｃｏｌ,ＰＥＬＡ）包裹乙肝表面抗原（ＨＢｓＡｇ）微球。微球外观规整,平均粒径２．１７μｍ,抗原包裹量达１．２５％,包裹效率７１．８％。经聚丙烯酰胺凝胶电泳（ＰＡＧＥ）检测,ＨＢｓＡｇ在微球制备过程中保持了结构完整性。以乙肝常规铝佐剂疫苗为对照,ＢＡＬ     

离子型表面活性单体存在下的MMA／BA乳液聚合（I）：表面？…

合成了两种离子型表面活性单体（Ｓｕｒｆｍｅｒ）－磺化－十二醇－烯丙基甘油－丁二酸酯钠盐（ＺＣ－Ｌ）和磺化－十二醇－甲基丙烯酰甘油－丁二酸酯钠盐（ＺＤ－Ｌ）。着重研究了ＺＣ－Ｌ的结构、表面张力行为、均聚及共聚能力。实验结果表明,不同Ｓｕｒｆｍｅｒ用量以及不同固含量下,ＭＭＡ／ＢＡ／Ｓｕｒｆｍｅｒ、ＭＭＡ／Ｓｕｒｆｍｅｒ及ＢＡ／Ｓｕｒｆｍｅｒ共聚乳液的表面张力较高,说明Ｓｕｒｆｍｅｒ已通过共聚结合在乳     

新型大溶性大π共轭高分子—聚吡咯—{2,5—[双（对二甲氨基苯甲烯）]}？…

该研究合成了一种新型水溶性大π共轭高分子－聚吡咯－｛２,５－〔二（对二甲氨基苯甲烯）〕｝（ＰＰＤＭＡＢ）,它地强酸的水溶液,在１ｍｏｌ／Ｌ的盐酸中溶解度为０．５～１．０g／１００mＬ,通过ＥＡ、ＸＰＳ、ＦＴ－ＩＲ、ＵＶ－Ｖｉｓ－ＮＩＲ、Ｉｎ－ｓｉｔｕＵＶ－Ｖｉｓ－ＮＩＲ对ＰＰＤＭＡＢ进行了结构表征。通过质子化、碘掺杂、浓硫酸（９８％）掺杂等处理,ＰＰＤＭＡＢ的电导率提高２～４个数量组（＆＝１－＾－７     

硫酸化高山红景天多糖(RSASL)的制备及鉴定

从高山红景天中分离出一种酸性杂多糖（ＲＳＡ）．该多糖由阿拉伯糖（Ａｒａ）、鼠李糖（Ｒｈａ）、半乳糖（Ｇａｌ）、木糖（Ｘｙｌ）、葡萄糖（Ｇｌｃ） 与半乳糖醛酸（ＧａｌＡ）组成,其单糖摩尔比为１．００∶３ ．２３∶０ ．２６∶０ ．３４∶０ ．８４∶１０．２４．用氯磺酸－吡啶法制备硫酸化高山红景天多糖（ＲＳＡＳＬ）．用离子色谱法测定ＲＳＡＳＬ 中Ｓ的质量分数为１１．０１％ ,其硫酸基取代度为０．８５．用红外光谱,紫外光谱,Ｓｅｐｈａｒｏｓｅ ＣＬ－４Ｂ柱层析,激光解吸电离飞行时间质谱等方法鉴定,ＲＳＡＳＬ均显示了多糖硫酸酯的特征     

BIS-PER(POLY)FLUOROALKYLATION OF PARA-SUBSTITUTED PHENOLS BY R_FI/Na_2S_2O_4 REAGENT SYSTEM

ＢＩＳ－ＰＥＲ（ＰＯＬＹ）ＦＬＵＯＲＯＡＬＫＹＬＡＴＩＯＮＯＦＰＡＲＡ－ＳＵＢＳＴＩＴＵＴＥＤＰＨＥＮＯＬＳＢＹＲ_ＦＩ／Ｎａ_２Ｓ_２Ｏ_４ＲＥＡＧＥＮＴＳＹＳＴＥＭ￥ＷｅｉＹｕａｎＨｕａｎｇ；ＨｏｎｇＢｉｎＹｕ（ＳｈａｎｇｈａｉＩｎｓｔｉｔｕｔｅｏｆ...     

SYNTHESIS AND VESICLES OF A DOUBLE-CHAIN GLYCOLIPID

ＳＹＮＴＨＥＳＩＳＡＮＤＶＥＳＩＣＬＥＳＯＦＡＤＯＵＢＬＥ－ＣＨＡＩＮＧＬＹＣＯＬＩＰＩＤ￥ＺｉＣｈｅｎＬＩ；ＷｅｉＨＥ；ＦｕＭｉａｎＬＩ（ＤｅｐａｒｔｍｅｎｔｏｆＣｈｅｍｉｓｔｒｙＰｅｋｉｎｇＵｎｉｖｅｒｓｉｔｙＢｅｉｊｎｇ１００８７１）Ａｂｓｔｒ...     

THE SYNTHESIS OF 4，5－BIS（4＇－BROMOBENZYLTHIO）－1，3－DITHIOLE－2－THIONE WITH ONE DIMENSIONAL INTERMOLECULAR INTERACTIONS

ＴＨＥＳＹＮＴＨＥＳＩＳＯＦ４，５－ＢＩＳ（４＇－ＢＲＯＭＯＢＥＮＺＹＬＴＨＩＯ）－１，３－ＤＩＴＨＩＯＬＥ－２－ＴＨＩＯＮＥＷＩＴＨＯＮＥＤＩＭＥＮＳＩＯＮＡＬＩＮＴＥＲＭＯＬＥＣＵＬＡＲＩＮＴＥＲＡＣＴＩＯＮＳ￥ＦａｎｇＱＩ（Ｉｎｓｔｉｔｕｔｅｏ...     

聚苯胺／聚乙烯醇导电复合膜的制备及性质研究

用较简单的化学氧化现场吸附聚合法（ｉｎ－ｓｉｔｕｐｏｌｙｍｅｒｉｚａｔｉｏｎ）制得了聚苯胺（ＰＡｎ）／聚乙烯醇（ＰＶＡ）导电复合膜．该膜具有较好的导电性和机械性能；其电导率可达５．８ｓ／ｃｍ，拉伸强度达１３ＭＰａ，断裂伸长率为１１０％左右．本文讨论了制备的各种条件对复合膜导电性能及力学性能的影响、稳定性及电化学活性；并采用循环伏安曲线、扫描电镜（ＳＥＭ）、ＦＴＩＲ谱及元素分析对该复合膜的结构和性能进行了表征．     

The inhibition abilities of multifunctional polyelectrolytes for silica scale formation in cooling water systems: role of the nonionic functional group

The abilities of multifunctional polyelectrolytes to enhance aluminum hydroxide dispersion and inhibit silica scale formation were examined in a pilot cooling water system. The following multifunctional polyelectrolytes were studied: a terpolymer of acrylic acid (AA), 2-acrylamide-2-methyl propane sulfonic acid (SA) and N-vinylpyrrolidone (NVP) (P(AA/SA/NVP)), acrylic acid homopolymer (P(AA)) and a copolymer of AA and SA (P(AA/SA)). The order of inhibition ability was P(AA/SA/NVP)>P(AA/SA)>P(AA), and was consistent with that of the dispersing ability for aluminum hydroxide. Other terpolymers incorporating different nonionic monomers were also examined and factors affecting their inhibition abilities were investigated, based on interaction energies calculated by density functional theory. Based on the correlation between scale inhibition abilities and interaction energies, we elucidated that the effective nonionic monomer of terpolymer for silica scale inhibition had low affinity for aluminum hydroxide and high affinity for H(2)O and Si(OH)(3)O(-). The affinities of nonionic monomer for aluminum hydroxide and H(2)O suggested that there was proper conformation of polyelectrolyte adsorbed for effectively dispersing aluminum hydroxide. Also, high affinity of nonionic monomer for Si(OH)(3)O(-) suggested that interacting Si(OH)(3)O(-) is an important role of inhibition of silica scale formation.     

聚-4-偶氮磺酸基苯乙烯与四-(三甲氨基苯基)-卟啉的自组装膜及其光电转换性能

聚-4-重氮基苯乙烯(PDS)在碱性水溶液下通过与Na₂SO₃反应,制备了聚-4-偶氮磺酸基苯乙烯(PDSS).作为负离子聚电解质PDSS能与四-(三甲氨基苯基)-卟啉(TTMAP)通过离子相互作用进行层-层自组装.光照下该组装膜中的离子键转变为共价键,结果是组装膜对极性溶剂和盐水溶液变为非常稳定,从而能直接在KCl水溶液中测定其光电流.结果表明,该组装膜具有良好的光电转换性质.     

Conformational effect on small angle neutron scattering behavior of interacting polyelectrolyte solutions: a perspective of integral equation theory

We present small angle neutron scattering (SANS) measurements of deuterium oxide (D(2)O) solutions of linear and star sodium poly(styrene sulfonate) (NaPSS) as a function of polyelectrolyte concentration. Emphasis is on understanding the dependence of their SANS coherent scattering cross section I(Q) on the molecular architecture of single polyelectrolyte. The key finding is that for a given concentration, star polyelectrolytes exhibit more pronounced characteristic peaks in I(Q), and the position of the first peak occurs at a smaller Q compared to their linear counterparts. Based on a model of integral equation theory, we first compare the SANS experimental I(Q) of salt-free polyelectrolyte solutions with that predicted theoretically. Having seen their satisfactory qualitative agreement, the dependence of counterion association behavior on polyelectrolyte geometry and concentration is further explored. Our predictions reveal that the ionic environment of polyelectrolyte exhibits a strong dependence on polyelectrolyte geometry at lower polyelectrolyte concentration. However, when both linear and star polyelectrolytes exceed their overlap concentrations, the spatial distribution of counterion is found to be essentially insensitive to polyelectrolyte geometry due to the steric effect.     

Effect of layer integrity of spin self-assembled multilayer films on surface wettability

We investigated the correlation between surface wettability and internal structure of polyelectrolyte (PE)/PE and PE/inorganic multilayer films prepared by the spin self-assembly (SA) method. Spin self-assembled poly(allylamine hydrochloride) (PAH)/poly(sodium 4-styrenesulfonate) (PSS) multilayer films deposited from PE solutions of 10 mM show the distinct oscillation in contact angles with variation of the outermost PE layer, representing the saturated values in contact angles of individual PAH and PSS layers. These contact angles are also well consistent with the angles measured from respective PE layers (i.e., PAH and PSS) of the spin SA (PAH/CdS-COO-) and (CdS-NH3+/PSS) films carrying the flat interface between PE and inorganic CdS nanoparticle layers as confirmed by X-ray reflectivity. Furthermore, based on the contact angle of CdS-NH3+ layer in the ordered (CdS-NH3+/PSS) films, the change in surface wettability of CdS-NH3+ layers of two different spin SA (CdS-NH3+/poly(methacrylic acid) (PMAA)) multilayer films with ordered and disordered internal structure is also investigated. The films with ordered and disordered internal structure were fabricated by the pH adjustment of PMAA. The CdS-NH3+ layer in both CdS-NH3+/PSS and CdS-NH3+/PMAA multilayer films with the ordered internal structure has the contact angle of about 25 +/- 2 degrees irrespective of the PSS or PMAA sublayer. As a result, the same surface wettability of PE or inorganic layers, despite different sublayers, strongly indicates that the spin SA method in optimum condition allows the top surface to be completely covered with a low level ofinterdigitation with a sublayer at each deposition step, and this leads to the conclusion that physical and chemical characteristics of the sublayers have no significant influence on those of the outermost layer.     

Aggregation-induced emission-active antibacterial hydrogel with self-indicating ability for real-time monitoring of drug release process

Although antibacterial hydrogels are emerging as promising biomaterials for effective inhibition of bacterial infections, monitoring their dynamic release behaviors in a visual manner remains greatly challenging. Herein, non-conjugated luminescent polymers (NCLPs) with aggregation-induced emission (AIE) characteristics are used for the first time to develop a visualization strategy to monitor the release process of the drug-loaded hydrogel. The novel antimicrobial peptide polymers with intrinsic AIE effect, namely nanoengineered peptide-grafted hyperbranched polymers (NPGHPs), are encapsulated in an anionic polyelectrolyte to construct the AIE-active fluorescent polymeric hydrogel (NPGHPs/SA gel). Interestingly, the rigid environment mediated by hydrogen bonding and electrostatic interaction contributes to promoting the unconventional luminescence of fluorescent clusters. Moreover, the successive drug release process of NPGHPs/SA gel can be tracked in real time by using fluorescence microscopy. The hydrogel also has potent antibacterial activities against Gram-negative bacteria (E. coli, P. aeruginosa) and Gram-positive bacteria (S. aureus, B. subtilis). Overall, this work not only provides an advanced biomedical material with broad-spectrum antibacterial ability but also opens a facile avenue up for the investigation of drug release from gel systems.     

Interactions between Adsorbed Layers of a Low Charge Density Cationic Polyelectrolyte on Mica in the Absence and Presence of Anionic Surfactant

Interactions between two negatively charged mica surfaces across aqueous solutions containing various amounts of a 10% charged cationic polyelectrolyte have been studied. It is found that the mica surface charge is neutralized when the polyelectrolyte is adsorbed from a 10–50 ppm aqueous solution. Consequently no electrostatic double-layer force is observed. Instead an attractive force acts between the surfaces in the distance regime 250–100 Å. We suggest that this attraction is caused by bridging. Additional adsorption takes place when the polyelectrolyte concentration is increased to 100 and 300 ppm, and a long-range repulsion develops. This repulsive force is both of electrostatic and steric origin. The polyelectrolyte layer adsorbed from a 50 ppm solution does not desorb when the polyelectrolyte solution is replaced with an aqueous polyelectrolyte-free solution. Injection of sodium dodecyl sulfate (SDS) into the measuring chamber to a concentration of about 0.01 CMC (8.3 × 10⁻⁵M) does not affect the adsorbed layers or the interaction forces. However, when the SDS concentration is increased to 0.02 CMC (0.166 mM) the adsorbed layer expands dramatically due to adsorption of SDS to the polyelectrolyte chains. The sudden swelling suggests a cooperative adsorption of SDS to the preadsorbed polyelectrolyte layer and that the critical aggregation concentration between the polyelectrolyte and SDS at the surface is about 0.02 CMC. The flocculation behavior of the polyelectrolyte in solution upon addition of SDS was also examined. It was found that 0.16–0.32 mol SDS/mol charged segments on the polyelectrolyte is enough to make the solution slightly turbid.     

Diffusion of cationic polyelectrolytes into cellulosic fibers

The penetration of cationic polyelectrolytes into anionic cellulosic fibers was evaluated with fluorescent imaging techniques in order to clarify the mechanism and time scales for the diffusion process. The bulk charge of the cellulosic fibers indirectly creates a driving force for diffusion into the porous fiber wall, which is entropic in nature due to a release of counterions as the polyelectrolyte adsorbs. The individual bulk charges in the fiber cell wall also interact with the diffusing polyelectrolyte, such that the polyelectrolyte diffuses to the first available charge and consequently adsorbs and remains fixed. Thus, subsequent polyelectrolyte chains must first diffuse through the adsorbed polyelectrolyte layer before adsorbing to the next available bulk charges. This behavior differs from earlier suggested diffusion mechanisms, by which polyelectrolytes were assumed to first adsorb to the outermost surface and then reptate into the pore structure. The time scales for polyelectrolyte diffusion were highly dependent on the flexibility of the chain, which was estimated from calculations of the persistence length. The persistence length ultimately depended on the charge density and electrolyte concentration. The charge density of the polyelectrolyte had a greater influence on the time scales for diffusion. High charge density polyelectrolytes were observed to diffuse on a time scale of months, whereas the diffusion of low charge density polyelectrolytes was measured on the order of hours. An influence of the chain length, that is, steric interactions due the persistence length of the polyelectrolyte and to the tortuosity of the porous structure of the fiber wall, could only be noted for low charge density polyelectrolytes. Increasing the electrolyte concentration increased the chain flexibility by screening the electrostatic contribution to the persistence length, in turn inducing a faster diffusion process. However, a significant change in the diffusion behavior was observed at high electrolyte concentrations, at which the interaction between the polyelectrolyte charges and the fiber charges was almost completely screened.     

On the monomer density of grafted polyelectrolyte brushes and their interactions

Most of the modern theories of grafted polyelectrolyte brushes are valid only for moderate stretching of the polyelectrolyte. However, particularly at low ionic strength and high grafting densities, even a moderate charge of the polyelectrolyte can generate a strong stretching. A simple mean field model for strongly stretched grafted polyelectrolyte brushes is suggested, based on an approximate calculation of the partition function of a polyelectrolyte chain. It is shown that the average Boltzmann factor of a possible chain configuration can be approximated by the Boltzmann factor of a configuration with a constant monomer distribution, for which the free energy can be readily obtained. The monomer density in the brush and the interaction between two surfaces with grafted polyelectrolyte brushes could be calculated as a statistical average over all possible configurations. Some simple analytical results are derived, and their accuracy is examined. The dependence of the brush thickness on the electrolyte concentration is investigated, and it is shown that the trapping of a fraction of counterions in the brush influences strongly the thickness of the brush. When two surfaces with grafted polyelectrolyte brushes approach each other more rapidly than the ion diffusion parallel to the surface, the trapping of the counterions between the brushes can affect the interactions by orders of magnitude.     

Phase separation in solutions of polyelectrolyte complexes: The decisive effect of a host polyion

Boundaries of the existence of insoluble polyelectrolyte complexes in solutions of nonequimolar mixtures of quaternary polyamines and polycarboxylates of various degrees of polymerization have been determined with turbidimetric titration. It has been shown that in salt-free media the position of critical points expressed as the ratio between the charge numbers of polymer components in a mixture depends on the chemical nature of the host polyelectrolyte (polycation or polyanion) but does not depend on either the nature of the guest polyelectrolyte or the degree of polymerization of mixture components. Upon addition of a low-molecular-mass polyelectrolyte, the heterogeneous region widens. The shorter the host polyelectrolyte relative to the guest polyelectrolyte, the more pronounced this effect. Based on the thermodynamic state of the systems under examination, an explanation of this effect is confirmed by the velocity sedimentation data.     

Simulations and scattering functions of polyelectrolyte–macroion complexes

Using Monte Carlo simulations of complex formation between a polyelectrolyte chain and an oppositely charged macroion, we calculated the scattering function of the polyelectrolyte chain. We investigated the case of the isolated polyelectrolyte chain and studied the effect and influence of key parameters such as the ionic concentration of the solution, polyelectrolyte length and intrinsic rigidity on the scattering function. Then, we focused on the polyelectrolyte–macroion complex by calculating the structure factor S(q) of the adsorbed polyelectrolyte chain. Typical conformations ranging from coils, extended chains to solenoids are revealed and the corresponding S(q) analysed. The effects of ionic concentration, chain length and intrinsic rigidity and relative size ratio between the polyelectrolyte and the macroion are investigated. Important effects on the structure factor of the adsorbed polyelectrolyte are observed when the macroion is partially or totally wrapped by the polyelectrolyte. Distance correlations between the polyelectrolyte monomer positions at the surface of the macroion induce the formation of peaks in the fractal regime of S(q). For semiflexible chains, when solenoid conformations are observed, the position of the peaks in the fractal regime corresponds directly to the separation distance between the turns. The formation of a protruding tail in solution is also observed through the formation in the fractal regime of a linear domain.This revised version was published online in November 2004 with corrections to the authors.