水溶性高分子对激光热透镜分析的增强作用

本文研究了水溶性高分子对激光热透镜分析的增强作用。结果表明，水溶性高分子的加入，改变了测定体系的热物理特性和显色体系的微环境。不但提出了热透镜分析的灵敏度，而且增强了显色体系的稳定性。在水溶性高分子存在下，对土壤中水溶性磷及痕量碘进行了高灵敏度的测定。     

表面活性剂与高分子链混合体系的模拟

计算机模拟了高分子链对表面活性剂胶束形成过程的影响，以及高分子链构象性质随胶束化过程的变化.结果表明,当高分子链与表面活性剂之间的相互作用强度超过临界值后，高分子链的存在有利于表面活性剂胶束的形成.临界聚集浓度（CAC）与临界胶束浓度（CMC）的比值CAC/CMC随高分子链长的增大和相互吸引作用的增强而减小.在CAC之前，高分子链与表面活性剂分子只有动态的聚集；但在CAC之后，表面活性剂胶束随表面活性剂浓度X的增加而增大，并静态地吸附在高分子链上，形成表面活性剂/高分子聚集体.随着表面活性剂分子的加入，高分子链的均方末端距和平均非球形因子先保持恒定；从X略小于CAC开始， 和快速减小，至极小值后又逐渐增大.模拟结果支持高分子链包裹在胶束表面的实验模型.     

高分子聚合物对激光热透镜分析的增强作用

本文报道非水溶性高分子对激光热透镜在痕量金分析中的增强作用，结果表明，聚氯乙烯（ＰＶＣ）能改变体系的热物理特性，并使体系最大吸收波长蓝移，从而增强热透镜光谱（ＴＬＳ）的信号强度，该方法的分析灵敏度比分光光度法高三个数量级，成功地用于化探样品中痕量金的测定。     

利用高分子多基元协同效应增强脂质体稳定性的研究

通过合成接枝胆固醇的壳聚糖水溶性高分子，并利用所接枝胆固醇的插膜能力，诱导高分子贴附于脂质体表面，形成高分子-脂质体复合物.研究发现，壳聚糖水溶性高分子可以起到屏蔽膜表面电荷的作用，同时该体系利用高分子链上多位点修饰的疏水基团与磷脂分子之间的疏水作用和高分子多基元之间共价连接的协同效应，增强了脂质体的抗融合及抗表面活性剂能力.该复合策略制备过程简便快捷，在体外实验中已展现出良好的稳定性，在长循环药物递送方面具有潜在的应用.     

水溶性高分子聚集行为荧光非辐射能量转移研究进展

评述了近几年荧光非辐射能量转移有疏水改性聚电解质的疏水聚集、高分子水溶液相变伴随的分子链塌陷、水溶性高分子与表面活性剂的相互作用等研究中的新进展,阐明了非辐射能量转移技术在水溶性高分子研究中的重要作用。     

疏水化水溶性聚电解质的增粘作用

疏水化水溶性聚电解质是一种大分子主链或侧链上含有少量疏水基团的新型水溶性功能高分子材料,在水溶液中具有良好的耐盐耐温增粘作用和贮存稳定性。对该类聚电解质的特殊增粘作用及分子结构、聚合物浓度、无机盐、机械剪切作用、ｐＨ、温度、表面活性剂、老化时间及与其他疏水化水溶性聚合物作用等影响因素进行了综述。     

高分子表面活性剂在固/液界面上的吸附形态

采用紫外光谱、XPS研究了羧甲基纤维素型高分子表面活性剂在硅胶 /水界面上的吸附形态 ,结果表明随着高分子表面活性剂溶液浓度增大 ,分子在硅胶表面的吸附由单层逐渐变为多层 ,生成半胶束结构 .     

聚合物对非离子十二烷基聚氧乙烯聚氧丙烯醚浊点的影响

测定了水溶性高分子聚乙二醇(PEC1000、PEG2000、PEG6000)和聚乙烯吡咯烷酮(PVP-K30、PVP-K90)对三种非离子表面活性剂十二烷基聚氧乙烯聚氧丙烯醚C12H25O(EO)m(PO)nH(LS36,m=3,n=6;LS5,m=4,n=5;LS54,m=5,n=4)浊点的影响.结果表明,聚乙二醇(PEG)可使三种表面活性剂水溶液浊点降低;而聚乙烯吡咯烷酮(PVP)随其浓度增加,表面活性剂溶液浊点先升高然后又下降;浊点下降程度与聚合物浓度和分子量有关.     

共聚物/表面活性剂体系微观与宏观粘度

高分子与表面活性剂的相互作用，无论从基础研究还是应用研究均很有意义＊．表面活性剂和高分子相互作用往往可以使高分子链的的象变化，例如通过生成分子缔合复合作问（associatedcomPleX），改变高分子链的静电相互作用，可引起高分子链的舒展和卷曲．另一方面，高分子也影响表面活性剂的物理化学性质．例如，溶液表面张力、粘度、电导、表现临界胶束浓度（＊＊C）和聚集数（＊叫等物理参数。‘］．在实用方面，在高分子和表面活性剂相互作用的复合体中，表面活性剂分子排列接近生物膜结构，可作为模拟生物酶催化的模型体系问．由超高分…     

激光热透镜分析法测定土壤中水溶性磷

采用激光热透镜分析法进行了土壤中水溶性磷的测定。研究了测定磷的各种影响因素及土壤中水溶性磷的浸提率与固液比和浸提时间的关系，表明聚乙烯醇的存在能增强热透镜信号强度，并使显色体系稳定５ｈ以上。采用该方法进行土壤中水溶性磷的测定，磷含量在１．５～３０μｇ／Ｌ之间与热透镜信号强度成线性关系，检出限为０．３μｇ／Ｌ。为土壤分析中痕量磷的测定提供了一种高灵敏度分析方法。     

Matrix effects in thermal lens spectrometry: influence of salts, surfactants, polymers and solvent mixtures

In this paper, we present an overall view of the matrix effects that can change or alter the signal in thermal lens spectrometry and we report the main works published in this field. The addition of salts, surfactants and polymers in aqueous solutions or the use of solvent mixtures is often needed in a variety of applications either to enhance the sensitivity of the thermal lens method or more generally because such media are required in the separation process prior to thermal lens detection. In most cases, matrix effects result in small changes in the thermo-optical properties of the solution and small signal variations. However, most important signal alterations can arise from the Soret effect. In binary mixtures as well as in solutions with macromolecular species which are initially homogeneous, the temperature gradient will induce the migration of molecules and the formation of a concentration gradient. This results in the formation of a concentration-dependent refractive index gradient which adds to the temperature-dependent refractive index gradient and contributes to the formation of a new signal. This effect can seriously alter the analytical signal and lead to erroneous interpretation of the experimental data. In contrast, time-resolved measurements can help in separating both signal components and have allowed to derive mass-diffusion times and mass-diffusion coefficients for a variety of micelles and polymers.     

Studies on the effect of surfactants on the extraction rate by laser thermal lens spectrometry

The effect of different kinds of surfactants on the extraction process of Nile Blue-I- was investigated by laser thermal lens spectrometry . It was shown that the surfactants could accelerate or decelerate the extraction rate by varying the extractive's solubility and the interfacial tension of the extraction solution. The higher the concentration of surfactants was, the more obvious the effect.     

Studies of surfactant/water systems near the critical micellar concentration using thermal lens spectroscopy

A novel application of photothermal spectroscopy to the study of surfactant-water systems near the critical micellar concentration is reported. The thermal lens signal was induced by a slightly soluble dye and was measured with a dual-beam thermal lens spectrometer.For the two surfactants considered: nonyl phenol and Triton X-100, sharp variations of the thermal lens signal were observed at the critical micellar concentration (CMC), namely an increase for nonyl phenol and a decrease for triton X-100. These effects are arguably related to micelle formation.Our work serves as an initial assessment of the potential of the technique for the study of disperse systems of a higher complexity or dark systems where conventional techniques are impossible to apply.     

Miniaturized thermal lens and fluorescence detection system for microchemical chips

We have developed a miniaturized two-way detection system using thermal lens and fluorescence spectroscopies for microchip chemistry. The system was composed of laser diode (LD) modules, fiber-based optics combined with a gradient index lens, and miniaturized detection units for thermal lens and fluorescence signals. The detection limits in the thermal lens and fluorescence spectroscopies were 6.3 x 10(-9)M for Ni(II) phthalocyanine tetrasulfonic acid and 3.0 x 10(-9)M for cy5, respectively. The performance of the system with the miniaturized thermal lens was equivalent to that of a conventional thermal lens microscope. The fluorescence sensitivity was comparable to sensitivities offered by conventional miniaturized systems.     

Multi-wavelength thermal lens spectrophotometer

A novel four-wavelength pump-probe configuration thermal lens spectrophotometer that is capable of simultaneously measuring thermal lens signals at four different wavelengths has been developed. The four excitation beams were derived from the same argon ion laser, which operated in a multi-line mode. The sample was sequentially excited by these four and the corresponding thermal lens signals were monitored by a He-Ne laser. Compared with other existing thermal lens apparatus, this four-color spectrophotometer has advantages that include its ability to provide identification of the analyte (as the ratios of the signals at four different excitation wavelengths) and to analyze simultaneously four-component samples without the need for any prior sample preparation. With this apparatus and with the use of 6-mW excitation beams modulated at 1.02 Hz, the detection limit for four-component samples is estimated to be about 10^?9 M, which is similar to the detection limit obtained for a one-component sample using a single-wavelength system.     

Thermal and rheological study of polysaccharides for enhanced oil recovery

Enhanced oil recovery process is based on the injection of chemical products (e.g. polymers, surfactants, gases) or thermal energy (originating from the injection of e.g. steam, hot water, in situ combustion) to recover crude oil. One of these processes use polymer solution to mobilize the oil in the reservoir. In this work the thermal decomposition kinetic of xanthan gum, guar gum and a blend (50/50 mass/mass%) was studied according to Ozawa–Flynn–Wall method. According to the kinetic analysis, the studied systems were copmpatible. The rheological behavior of the samples was studied in distilled water and seawater at different temperatures. Only the blend was studied in distilled water presented synergism (enhancement in material properties like stability and viscosity) which was confirmed through rheology.     

Synthesis of 2-phenoxy-2-phenylethyl acrylate and copolymerization with 2-phenylethyl acrylate: Estimation of monomer reactivity ratios,thermal and optical properties

A new aromatic based monomer 2-phenoxy-2-phenylethyl acrylate (PPEA) was synthesized. Copolymers of PPEA with 2-phenylethyl acrylate (PEA) were prepared by free radical polymerization. The reactivity ratios were estimated using various graphical methods. Structural parameters of the copolymers were obtained by calculating the dyad monomer sequence fractions and the mean sequence length. Optical properties of polymers such as refractive indices and UV-Visible absorption were investigated. The glass transition temperature and thermal degradation behavior of the copolymers were studied. Combined with the RI, transparency and thermal properties, prepared copolymers hold great promise as materials for intraocular lens applications.     

Influence of Surfactants on the Microstructure and Performance of PDMS-E Grafted Gelatin Films

Polydimethylsiloxane grafted gelatin (PGG) polymers were prepared from mono-epoxy terminated polydimethylsiloxane (PDMS-E) macromonomer and gelatin, and surfactants were used to enhance the compatibility of the two polymers phases. The influences of surfactants, including sodium dodecyl sulfate (SDS), sodium dodecyl benzene sulfonate (SDBS), dodecyl trimethylammonium bromide (DTBA), and Tritox-100, on the microstructure and performance of polymers films were researched. XPS and FTIR results confirmed that PDMS-E was successfully grafted to gelatin chains. The results of SEM, DSC, TGA and surface contact angle indicated that microstructure of the PGG/SDS film was mainly controlled by the grafting effect on the gelatin matrix, and a tightly cross-linked network structure formed in PGG/SDBS film. However, few changes were present in the DTAB and Tri-100 systems. Surfactants played a crucial role in deciding the detailed microstructure of the grafted gelatin films, and induced the changes of hydrophobicity, flexibility and thermal properties of the polymer films.     

Enhance effect of surfactants on the photoluminescence and photostability of water-soluble poly(phenylene ethynylene)

The interaction between the water-soluble anionic fluorescence conjugated polyelectrolytes PPESO 3 (poly[2,5-bis(3-sulfonatopropoxy)-1,4-phenylethynylene-alt- 1,4-poly(phenylene ethynylene)]) and various surfactants has been studied in aqueous solution by UV-vis absorption spectra and fluorescence spectra. With the addition of surfactants, the aggregations of polymers are broken up. For eliminating the self-quenching effect of the fluorescent polymers, the photoluminescence of PPESO 3 is dramatically enhanced. The photoluminescence of PPESO 3 can be enhanced 6- to 12-fold with the addition of different surfactants, and at higher concentration of surfactants, the photostability of PPESO 3 is also highly increased. A "micelle incorporation model" is proposed to explain the enhancement of photostability. To deeply understand the interaction processes between PPESO 3 and surfactants, we systematically studied the fluorescence spectra changes of PPESO 3 and the dynamic processes at different CTAB concentrations. All results prove the surfactants can simultaneously enhance the photoluminescence and photostability of water-soluble conjugated polyelectrolytes, and this method is very simple and powerful.     

Thermal decomposition of polypyrroles

The thermal stability of polypyrrole (PPy) samples has been studied by thermogravimetry/mass spectrometry and pyrolysis-gas chromatography/mass spectrometry in inert atmospheres. PPy has been prepared by chemical oxidative polymerization using ferric sulfate as an oxidant and anionic surfactants, such as dodecylbenzenesulfonic acid and sodium dodecylbenzenesulfonate as co-dopants. For comparison we have studied polypyrrole (PPy-SO₄) prepared without any additive. It was found that the presence of anionic surfactants improved the thermal stability of PPy. The decomposition of PPy doped with ferric sulfate and anionic surfactants occurs at relatively high temperature indicating that chemical interactions exist between the polymer and the surfactants.