Comparative studies of electrochemically deposited poly(o-toluidine) and poly(m-toluidine) films

Under galvanostatic deposition conditions poly(o-toluidine) exhibits a higher rate of polymerization than poly(m-toluidine). This observation is supported by results obtained by different characterization techniques such as spectrophotometry, scanning electron microscopy and thermogravimetric analysis. The monomer concentration was found to be the predominant parameter in obtaining selectively a conducting salt phase in both cases. However, the morphology of these polymeric films does not reveal any particular relationship with monomer concentration; instead a mixed morphology, i.e. a combination of granules and fibres, is observed. Finally, the thermal stability of poly(m-toluidine) is lower than that of poly(o-toluidine) with a shift of 190°C in the final decomposition temperature.     

Preparation and sensor properties of poly (o-toluidine) film

Summary An amperometric biosensor for glucose was constructed in a one-step procedure by the electropolymerization of o-toluidine in the presence of glucose oxidase on Pt substrates in KCl aqueous electrolyte at a potential of 0.5 V vs Ag / AgCl. The amperometric responses of the prepared polymeric biosensor to the glucose were measured at a potential of 0.7 V in PBS solution. Results showed that this polymeric sensor exhibited a fast amperometric response time (4–5 s) and a linear range up to 6 mM glucose with poor stability. Also, it was seen that biosensor responded successfully to glucose injections in the presence of some interfering species such as lactose, sucrose and urea. Received: 27 January 1999/Revised version: 18 May 1999/Accepted: 18 May 1999     

NaPSS溶液中2，6－ANS探针的荧光偏振研究

本文用荧光偏振技术，测定了聚苯乙烯磺酸钠在无盐和有盐的水溶液中，探针的荧光偏振。结果表明：探针荧光偏振值随外加盐种类、浓度的变化而变化，在相同外加盐浓度下，荧光偏振值的大小次序为：ＬｉＣｌ＞ＮａＣｌ＞ＫＣｌ。并研究了温度对探针荧光偏振的影响，计算了探针的旋转松驰时间。     

混合表面活性剂水溶液自组装特性研究

在以表面活性剂为模板的仿生合成中,模板的自组装特性是关键环节。由于混合胶团的存在,两种表面活性剂的水溶液体系的效能高于单一表面活性剂溶液;利用试验优选合适的混合表面活性剂用于仿生合成,耗费时间长,成本高。本文从热力角度出发,分析了混合成胶自由能的影响,建立了离子 非离子混合表面活性剂的自组装模型,利用该模型模拟考察了混合表面活性剂的混合临界胶团浓度和胶团组成等参数,得到了其影响因素及作用规律,并进行了部分试验验证,二者吻合得较好。     

Self-Assembly of Poly(Amino Acid)s Mediated by Secondary Conformations

Self-assembly of block copolymers has recently drawn great attention due to its remarkable performance and wide variety of applications in biomedicine, biomaterials, microelectronics, photoelectric materials, catalysts, etc. Poly(amino acid)s (PAAs), formed by introducing synthetic amino acids into copolymer backbones, are able to fold into different secondary conformations when compared with traditional amphiphilic copolymers. Apart from changing the chemical composition and degree of polymerization of copolymers, the self-assembly behaviors of PAAs could be controlled by their secondary conformations, which are more flexible and adjustable for fine structure tailoring. In this article, we summarize the latest findings on the variables that influence secondary conformations, in particular the regulation of order-to-order conformational changes and the approaches used to manage the self-assembly behaviors of PAAs. These strategies include controlling pH, redox reactions, coordination, light, temperature, and so on. Hopefully, we can provide valuable perspectives that will be useful for the future development and use of synthetic PAAs.     

基于纤维素模板的聚合物空心微球作为药物载体的性能研究及分析

以羟丙基纤维素为模板材料,分别采用不同的聚合方法制备了2种不同形态和结构的聚合物空心微球--聚N-异丙基丙烯酰胺-co-聚丙烯酸(PNIPAm-co-PAA)微凝胶和聚N-异丙基丙烯酰胺-聚丙烯酸(PNIPAm-PAA)水凝胶微囊。以盐酸阿霉素(Dox)作为模型药物,考察了聚合物空心微球作为药物载体的载药能力和体外释放性能。研究表明,PNIPAm-co-PAA微凝胶、PNIPAm-PAA水凝胶微囊和Dox分子能够通过正负电荷的相互吸引实现有效结合;载药微球具有良好的缓释性能,并对Dox的释放表现出明显的pH值敏感性和温度敏感性。体外细胞毒性实验表明,载药PNIPAm-co-PAA微凝胶、PNIPAm-PAA水凝胶微囊具有很高的抗肿瘤活性,细胞相对存活率均可达20%左右。PNIPAm-co-PAA微凝胶、PNIPAm-PAA水凝胶微囊在作为水溶性药物或蛋白类药物载体方面,具有潜在的应用价值,同时有望应用于木材胶黏剂防腐等。     

Nanoencapsulation of n-Octadecane Phase Change Material in Self-Assembled Polyelectrolyte by Soft Solution Technique

Nanoencapsulation of n-octadecane phase change material was performed by facile soft solution technique. An emulsion of n-octadecane and sodium dodecyl sulfate was prepared by high intensity sonication and then mixed with 1–6 mM of poly(diallyldimethylammonium chloride) (PDDA) solution. The capsules with globular core-shell structure were obtained via self-assembly of PDDA molecules coated on the primary emulsion droplets, described as PDDA encapsulated n-octadecane (PDDA-en-Oc). Average particle size and ζ-potential of PDDA-en-Oc increased with increasing of PDDA concentration due to the different PDDA conformation and thickness of capsules' shell. The smaller diameter of PDDA-en-Oc, the faster heat releasing and absorption were obtained. However, the increasing of PDDA concentration could improve the encapsulation efficiency, resulting in an increment of latent heat quantity. The PDDA-en-Oc capsules prepared from 4 mM PDDA with ～166 nm in size possessed the maximum latent heat and encapsulation efficiency (i.e., 124.4 J/g and 58%, respectively).     

聚酰亚胺中空纤维膜的热亚胺化及碳化的研究

聚酰亚胺（P1）是一种性能忧良的新型膜材料。就其在热亚胺化过程中的一些因素对膜性能影响及碳化过程中的PI膜结构变化怍一定的研究与分析讨论,从而推断其可能的结构变化,     

Anti-corrosive properties of waterborne polyurethane/poly(o-toluidine)-ZnO coatings in NaCl solution

The aim of this research was to prepare waterborne polyurethane (WPU) coating blended with a series of poly(o-toluidine)-nano ZnO composites and study its anti-corrosion performance after its application over carbon steel. The synthesized composites were characterized by X-ray diffractometry (XRD), Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), and scanning electron microscopy (SEM). The corrosion resistance of coatings with and without nano ZnO were studied in 3.5% NaCl solution at a temperature of 25?°C, by electro-chemical techniques such as potentiodynamic polarization measurements and electrochemical impedance spectroscopy (EIS). It was observed that the composite coating containing 7% poly(o-toluidine)-nano ZnO composite had higher corrosion resistance than poly(o-toluidine) and 14% poly(o-toluidine)-nano ZnO composite. The presence of appropriate amount of ZnO significantly improved the corrosion resistance, due to the formation of passive layer on steel surface and the synergistic effects of poly(o-toluidine) along with a suitable amount of nano-ZnO reduced the porosity of the coating surface.     

Control of Electrical Properties of Polyaniline

The electrical and material properties of polyaniline can be controlled on the molecular level, e.g. by copolymerization of aniline with p-phenylenediamine. Products having a resistivity from 10⁰ to 10⁹Ωcm can be obtained. On the supramolecular level, polyaniline dispersions comprising submicrometre particles can be used for the preparation of microstructured composites with water-soluble polymers such as poly(vinyl alcohol) or poly(N-vinylpyrrolidone). On the macroscopic level, the blending of polyaniline with an inorganic salt, ammonium sulphate, produced materials with a percolation threshold at 2·5vol% polyaniline. © 1997 SCI.     

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．     

Flow Properties of Ultrahigh-Molecular-Weight Poly(Methyl Methacrylate) in Semidilute Solutions

The article presents some Theological results obtained on a large domain of shear rates for semidilute solutions of ultrahigh-molecular-weight poly(methyl methacrylate) at different concentrations. The observed unusual behavior was explained as being due to the flow instabilities of long-chain polymers in an entangled state.     

聚苯胺／聚乙烯醇复合材料结构分析

复合技术是一种有效提高聚苯胺综合性能的方法.采用原位聚合法制备了溶解性较好的聚苯胺/聚乙烯醇复合材料.通过扫描电镜分析重点研究了聚苯胺/聚乙烯醇复合材料的结构.结果表明:聚苯胺能够在聚乙烯醇基体上均匀的聚合,且结构致密.     

聚3,4-乙烯二氧噻吩/聚苯胺复合材料的制备与性能

以过硫酸铵(APS)和FeCl3为复合氧化剂,采用原位化学氧化聚合法合成了导电聚3,4-乙烯二氧噻吩/聚苯胺(PEDOT/PANI)复合材料,研究了苯胺浓度及加入时间、复合氧化剂配比和复合乳化剂配比对复合材料性能的影响,并对复合材料进行了分析. 结果表明,PEDOT/PANI复合材料合成的较佳工艺条件为：3,4-乙烯二氧噻(EDOT) 0.6 mol/L、复合氧化剂 0.6 mol/L(FeCl3:APS=1:2, mol)、复合乳化剂 0.4 mol/L(SDBS:CTAB=2:3, mol)、复合掺杂剂1.2 mol/L(H2SO4:SSA=4:1, mol)及苯胺0.8 mol/L, EDOT聚合2 h后加入苯胺溶液继续反应8 h. 复合材料的导电性、结晶性和热稳定性比纯导电聚合物好.     

Synthesis of PEGylated poly(amino acid) pentablock copolymers and their self‐assembly

Pentablock copolymers with an ABCBA architecture were synthesized by ring‐opening polymerization of N‐carboxyanhydrides of l ‐leucine and γ‐benzyl l ‐glutamate using an α, ω‐diamino poly(ethylene glycol) (PEG) as macroinitiator. Three different PEGs with molecular weights of 2000, 4600 and 10 000 Da were used and the poly(amino acid) (PAA) block lengths were set to a combined 10 and 40, respectively, repeat units for p(l ‐Leu) and 40 repeat units for p(l ‐Glu). The molecular architecture of the resulting pentablock copolymers was determined by the order of monomer addition. The living character of the N‐carboxyanhydride ring‐opening polymerization enables the formation of multiblock copolymers. The degree of polymerization for the PAA blocks matched the monomer/initiator ratio. A structural switch element, which controls the hydrophilicity of the pentablock copolymers, was incorporated in the form of the p(l ‐Glu) blocks. The pentablock copolymers became water soluble after hydrolyzing the benzyl ester protective groups. The pentablock copolymers self‐assembled into polymeric aggregates ranging in size between 160 and 340 nm. Hydrogels formed readily if the central PEG block had a molecular weight of at least 4600 Da and the terminal A‐blocks consisted of p(l ‐Leu). SEM images confirmed the size ranges of the polymeric aggregates and showed non‐distinct spherical aggregates. © 2016 Society of Chemical Industry     

Hollow polymeric nanostructures—Synthesis, morphology and function

The development of reliable synthetic routes to polymeric nanostructures of well-defined composition, morphology and function is of scientific importance and technological interest. The generation of functional hollow polymeric nanostructures, hollow nanospheres and nanotubes in particular, can be achieved through direct and template-directed synthesis, core-shell precursors, and self-assembly of copolymers and polymer conjugates, as well as from dendrimers. The ability to prepare precursor macromolecules of well-defined structure and architecture has been substantially enhanced by recent advances in controlled radical polymerizations. The application and potential application of the hollow polymeric nanospheres and nanotubes as nanoreactors, and in diagnostics, encapsulation, controlled release, and other stimuli-responsive systems are also described.     

Self-Assembly of Polymers through Dynamic Coordination Chemistry and Hydrogen Bonding: Polymers from Mercury(II) Halides and Bis(amidopyridine) Ligands

The synthesis of hybrid organic–inorganic polymers by combination of mercury(II) halides with the ligand 1,5-bis(isonicotinamido)naphthalene, C₁₀H₆(NHCO-4-C₅H₄N)₂, 1. The compounds of formula [HgX₂(1)] form either linear (X = Cl, Br) or zig-zag (X = I) polymers and contain tetrahedral mercury(II) centers with bridging ligands 1. The polymers are further assembled by hydrogen bonding between amide groups. When X = Cl or Br, two-dimensional sheet structures are formed whereas, when X = I, a three-dimensional network is formed. A new polymeric form of [HgCl₂(Me₂SO)] is also described. Dedicated to Ian Manners for his pioneering research on organometallic polymers     

Conformational Transitions of High-Molecular-Weight Poly(Methyl Methacrylate) in Dilute Solutions

This article deals with the investigation of high-molecular-weight poly-(methyl methacrylate) dilute solutions. The conformational transitions were followed as a function of temperature and solvent nature (ethyl acetate, butyl acetate, monochlorobenzene, o-dichlorobenzene) by using ultraviolet (UV) spectrophotometry and viscometry. The systems involving ethyl acetate as a solvent presented some peculiarities in the temperature dependence of the UV spectra.     

N-异丙基丙烯酰胺凝胶在乙醇水溶液中的溶胀平衡

N-isopropylacrylamide (NIPAAm) was used to synthesize NIPAAm homopolymer (nonionized) and NIPAAm-sodium methacrylate copolymer (ionized). The swelling equilibria for both gels were obtained in aqueous solution of ethanol with concentration ranging from 0 to 100%(by mass) at 25℃. The swollen gel in water shrank first with the addition of a small amount of ethanol and then reswelled with further addition of ethanol showing not only a discontinuous volume phase transition but also a typical reentrant phenomenon. A thermodynamic model based on the UNIQUAC with the “free-volume“ contribution was applied to correlate and predict the swelling behavior of the poly(NIPAAM)-gels in ethanol-water mixture.