掺杂聚苯胺溶致液晶相的产生和表征

聚苯胺（PAN）具有共轭结构,从理论上满足形成液晶相的基本条件［1,2］．但由于聚苯胺难溶、难熔,长期以来对于聚苯胺溶液（尤其是浓溶液）或熔体的研究甚少．近年来,人们采用具有“增塑作用”的大分子功能质子酸对聚苯胺进行掺杂,获得可溶于多种有机溶剂中的掺杂态聚苯胺［3～5］．然而,聚苯胺溶液的结构与性能的特点及能否产生溶致液晶相等问题目前尚未见报道．为此,我们研究了十二烷基苯磺酸（DBSA）掺杂聚苯胺在有机溶剂中形成液晶相的条件,探讨了不同掺杂方法对PAN－DBSA的溶解性及形成液晶棺的影响;采用差式扫描量热分…     

XPS研究聚苯胺的竞争掺杂行为

采用X射线光电子能谱（XPS）方法对不同反应体系下化学合成的聚苯胺（PANI）的结构和掺杂状况进行了研究。发现盐酸（HCl）掺杂的聚苯胺在样品后处理过程中易发生脱掺杂行为;在十二烷基苯磺酸钠（SDBS）和盐酸共存体系下合成聚苯胺时,对阴离子DBS-和Cl-发生竞争掺杂行为。结果表明DBS-与带正电荷聚苯胺链结合,起到了掺杂和诱导聚苯胺可溶性的作用,它的N1s和S2p谱图与单独采用十二烷基苯磺酸（DBSA）掺杂聚苯胺的谱图相似。但SDBS-HCl复合体系比单独采用DBSA体系更为有利。     

掺杂率对乳液聚合制备聚苯胺结构性能的影响

对乳液聚合的十二烷基苯磺酸(DBSA)掺杂聚苯胺(PAn)进行不同pH值溶液浸泡处理。采用元素分析、红外光谱分析、X射线衍射及热失重分析等手段，研究了不同掺杂率对PAn结构性能以及PAn在普通有机溶剂中的溶解性能和导电性能的影响。结果表明：随DBSA掺杂率的增加，PAn的电导率及其在三氯甲烷中的溶解度增加，带有烷基长链的DBSA使PAn形成以DBSA为间隔的有序层状结构；而且合成的PAn-DBSA热稳定性良好。     

聚丙烯腈基聚合物电解质

详细介绍了锂离子电池用PAN（聚丙烯腈）基聚合物电解质的发展过程和制备方法，提出了PAN基凝胶型聚合物电解质所存在的主要问题，介绍了采用共聚和掺杂陶瓷材料对PAN的改性方法，并对聚合物电解质的离子传输机理作了初步探讨。     

表面活性剂对导电聚吡咯性能的影响

采用十六烷基溴化铵（CTAB）、十二苯磺酸（DBSA）、十二烷基硫酸钠（SDS）3种表面活性刘为软模板,过硫酸铵为氧化剂,在0℃冰水浴条件下制备导电聚吡咯。通过改变表面活性剂的种类和用量,考察其对聚吡咯形貌和性能的影响。用FTIR、XRD、SEM等对聚吡咯材料进行表征。研究表明：表面活性剂和PPy存在一定程度上的相互协同作用,添加表面活性剂能够直接调整聚吡咯分子的形貌;掺杂DBSA、SDS可合成球状结构聚吡咯,掺杂CTAB可合成棒状结构的聚吡咯,并且当”（PPy）：n（CTAB）-5时,合成的聚吡咯导电性能最好。     

四种方法合成单一手性聚苯胺纳米纤维研究

以过硫酸铵或2,3-二氯-5,6-二氰基-1,4-苯醌（DDQ）为氧化剂,单一手性樟脑磺酸作为诱导酸及掺杂剂,在有机溶剂、水-有机溶剂和水溶剂体系中,采用四种不同方法分别进行了单一手性聚苯胺纳米纤维合成研究。通过扫描电子显微镜（SEM）、紫外可见光谱（UV-VIS）、X射线衍射（XRD）和圆二色谱（CD）等手段对自组装法、界面聚合法、低聚物辅助法与二次掺杂法等四种方法制备得到聚苯胺纳米纤维的形貌、结构及光学活性进行表征,对比分析后发现四种方法合成的掺杂态聚苯胺纳米纤维形貌、结构相似,但溶剂体系会影响最终产物的光学活性：水溶剂、有机溶剂体系中,得到的聚苯胺纳米纤维光学活性相反。     

掺杂质子酸的类型对聚苯胺结构和电导率的影响

采用化学氧化聚合法以苯胺为单体，过硫酸铵为氧化剂，在不同质子酸的水溶液中合成聚苯胺，考察质子酸对聚苯胺电性能影响，并通过傅立叶红外吸收光谱（FTIR）和紫外可见光吸收光谱（UV－vis)研究聚苯胺掺杂前后结构的变化。结果表明，龙质子酸掺杂后聚 胺具有导电性是因为其分子链上电荷离城形成了共轭结构，具有不同质子酸中生成的聚苯胺氧化程度不同；分子链共轭程度与掺杂酸对阴离子大小有关，掺杂质子酸对阴离子越大，聚苯胺分子链共轭程度越大，电导率也就越高。     

苯胺在酪氨酸功能化的玻碳电极表面的聚合及应用——推荐一个综合化学实验

用电化学氧化法将酪氨酸（Tyr）通过C—N键共价键合在玻碳电极（GCE）表面,制备Tyr单层分子功能化的GCE（Tyr/GCE）。用循环伏安法在Tyr/GCE表面对苯胺进行电化学聚合,制备掺杂态聚苯胺（PAN）修饰的GCE（PAN-Tyr/GCE）。由于Tyr对PAN的掺杂作用,使PAN在中性甚至碱性介质中仍有较好的电化学活性,拓宽了聚苯胺的应用范围。用X射线光电子能谱（XPS）、红外光谱（IR）、紫外光谱（UV-Vis）及电化学方法对所得电极的结构和性能进行了表征。并研究了在中性介质中PAN-Tyr/GCE对抗坏血酸（AA）的电催化氧化。     

超临界二氧化碳制备聚合物微孔膜的研究进展

超临界二氧化碳做非溶剂制备聚合物微孔膜是一个新的研究热点,具有传质系数高、聚合物膜干燥速度快且不破坏结构、溶剂容易回收、CO2可循环使用、CO2的低毒性与环境友好性等特点.本文介绍采用超临界CO2制备聚合物微孔膜的热力学及动力学原理,重点介绍近年来采用此技术制备微孔膜的研究成果,如以聚苯乙烯（PS）、聚丙烯腈（PAN）、聚醚砜（PES）等为基体的微孔聚合物膜.     

聚丙烯腈在锂金属电池电解质中的应用

随着便携式电子设备、电动汽车和智能电网等快速发展，人们对高能量密度锂金属电池的关注日益增多。锂金属表面不均匀的剥落或沉积会导致锂枝晶生长，锂枝晶容易刺穿隔膜，存在引发电池短路的风险，而且高反应活性的锂金属会与电解液不断反应被消耗，生成不稳定的固体电解质界面（SEI）膜，造成不可逆的容量损失，因此兼顾高能量密度与高安全性是锂金属电池发展应用中亟需解决的关键科学问题。具有强吸电子基团（C≡N）的聚丙烯腈（PAN）聚合物与碳酸酯溶剂中C=O的相互作用能形成更稳定的SEI膜，PAN作为锂负极涂层还能抑制锂枝晶的生长；另外，PAN具有较低的最低未占据分子轨道、较高的电化学稳定性和较宽的电化学窗口，能作为锂金属电池的聚合物电解质，并匹配高电压正极，兼具高能量密度和高安全性，故PAN聚合物在锂金属电池的电解质中有着很大的应用潜力。本文从电解质的不同状态（液态、凝胶、固态）介绍了PAN聚合物在液态电解质中作为隔膜、锂负极保护层以及在凝胶电解质、固态电解质的最新研究成果，并对PAN聚合物在锂金属电池电解质中的发展趋势进行展望。     

Thermal conductivity and interfacial energy of solid Bi solution in the Bi–Al–Zn eutectic system

The equilibrated grain boundary groove shapes for solid Bi solution (Bi–6.1 at.%Zn–0.38 at.%Al) in equilibrium with the Bi–Al–Zn eutectic liquid have been observed from quenched sample with a radial heat flow apparatus. The Gibbs–Thomson coefficient, solid–liquid interfacial energy and grain boundary energy of solid Bi solution have been determined from the observed grain boundary groove shapes. The variations of thermal conductivity with temperature for solid Bi solution (Bi–6.1 at.%Zn–0.38 at.%Al) has been measured up to five degree below the melting temperature by using radial heat flow technique. The ratio of thermal conductivity of equilibrated Bi–Al–Zn eutectic liquid phase to solid Bi solution (Bi–6.1 at.%Zn–0.38 at.%Al) phase has also been measured with a Bridgman type growth apparatus at the melting temperature.     

Stability of electrons—monomers and dimers—in gamma-irradiated hydroxide glasses

The increase of temperature from 77 K brings about the retrapping of electrons and/or recombination processes manifested by the changes of absorption spectra and ESR signals. The new absorption bands at 700–840 nm, which belong to diamagnetic electron dimers, have been observed at 215–225 K. These species are connected with NaOH·X H₂O hydrates as it has been shown by near-IR spectra. The dispersive kinetic parameters of photobleaching of electrons—monomers and dimers—at 80 K have been measured.     

Methyl methacrylate-methyl isopropenyl ketone copolymers: Degradation under environmental conditions

Reactivity ratios for the radical copolymerisation of the methylmethacrylate (MMA) (1)/methyl isopropenyl ketone (MIK) (2) system have been evaluated at 60°C as r₁=0·97; r₂=1·09. Copolymers with MIK contents from 0 to 15% have been prepared. Films were exposed to sunlight under environmental conditions at ground level and buried under-ground at a depth of 9 cm and their photo-degradation, as measured by chain scissions and mechanical properties, was followed with exposure time. For the specimens at ground level, a clear dependence of degradation on sunlight exposure time and MIK content is observed, similar to that observed under laboratory conditions, whether in film or in solution. Negligible degradation was observed over a 2-year period in the buried specimens. Laboratory biodegradation tests seem to indicate that attack by microorganisms starts at a polymer molecular weight of about 20 000.     

Dielectric studies of different phases of a thin-layered ferroelectric liquid crystal with a small pitch and high spontaneous polarization

Dielectric spectroscopy of a ferroelectric liquid crystal with planar texture in the frequency range 100 Hz to 1 MHz has been carried out as a function of temperature from 25°C to 60°C at different DC fields varying from 0 to 12 kVcm^-1. From the measured dielectric strengths and relaxation frequencies, it is observed that the material has a S_c*-S_A* transition at 56·1°C and a S_A*-I transition at 58°C. The data of the S_c* phase have been assigned to the Goldstone mode. The rotational viscosity and elastic constant have been calculated from the observed data. The capacitance shows an abrupt drop at the critical DC field where unwinding of the helix occurs. The measured value of the critical field decreases with temperature and agrees to literature data from electrooptical experiments. On applying a DC field greater than 6·5 kV cm^-1 at room temperature, the liquid crystal shows the unwound S_c* and S_A* phases.     

Synthesis of new tripodal receptors—a ‘PET’ based ‘off-on’ recognition of Ag

A new set of tripodal receptors based upon an aromatic platform have been synthesized in high yields. The compounds have been characterized by spectroscopic techniques and by single crystal X-ray crystallography. These receptors are found to have good extraction ability and high transport rate for Ag(I). The receptor with imine linkages exhibits weak fluorescence emission bands at λ_max=413 and 540 nm, upon excitation at λ_max=365 nm. The fluorescence spectrum of the receptor shows enhancement in the intensity of the signal at 413 nm on binding with the Ag⁺ cation. No such significant changes are observed with other metal ions. An absorption at ∼365 nm is typical of an intraligand (π-π^∗) transition involving the imine chromophore, which produces a weak emission band at 413 nm due to quenching caused by PET from a neighboring -OH group. Participation of OH group in coordination to the metal ion reduces PET and an enhancement of fluorescence intensity is observed, signaling recognition of the metal ion.     

A thermoanalytical study of the cure of xylok 225 resin

The cure of Xylok 225 resin with a range of concentrations of hexamethylene tetramine has been studied by DTA, DTA-TG and DSC. The process has also been followed by IR spectroscopy. Two reaction peaks were observed during the cure, an exotherm occurring near to 150°C and an endotherm near to 250°C. The exotherm appeared to be affected by the concentration of hexamethylene tetramine, at a low concentration (4.8%) its onset was delayed until near 190°C, whilst at a higher concentration (13.0%) the heat of reaction was diminished. Both the exothermic and endothermic phases of cure were accompanied by evolution of volatiles.     

Catalytic adsorptive stripping voltammetric measurements of trace vanadium at bismuth film electrodes

Bismuth-coated glassy carbon electrodes have been successfully applied for catalytic adsorptive stripping voltammetric measurements of low levels of vanadium(V) in the presence of chloranilic acid (CAA) and bromate ion. The new protocol is based on the accumulation of the vanadium-chloranilic acid complex from an acetate buffer (pH 5.5) solution at a preplated bismuth film electrode held at −0.35 V (versus Ag/AgCl), followed by a square-wave voltammetric scan. Factors influencing the adsorptive stripping performance, including the CAA and bromate concentrations, solution pH, and accumulation potential or time have been optimized. The response compares favorably with that observed at mercury film electrodes. A linear response is observed over the 5-25 μg/L concentration range (2 min accumulation), along with a detection limit of 0.20 μg/L vanadium (10 min accumulation). High stability is indicated from the reproducible response of a 50 μg/L vanadium solution (n = 25; R.S.D. = 3.1%). Applicability to a groundwater sample is illustrated.     

Improved catalysis of Morita-Baylis-Hillman reaction. The strong synergic effect using both an imidazolic ionic liquid and a temperature

The effect of different catalytic conditions for the Morita-Baylis-Hillman reaction has been evaluated both experimentally and by chemometry. The use of either ultrasound at 0 °C, ultrasound with an imidazolic ionic liquid at 0 °C or the ionic liquid catalyst at 0 and 50 °C was systematically tested. A strong synergic effect, which significantly increases the reaction rates and yields, was observed when the reactions were performed using an imidazolic ionic liquid catalyst at both 0 and 50 °C.     

Dynamic small-angle x-ray scattering from crystalline polymers

The variation in small-angle x-ray scattering (SAXS) for samples of crystalline polymers subjected to oscillatory strains has been observed employing the 10-m SAXS apparatus with a two-dimensional position-sensitive detector at the National Center for Small-Angle Scattering Research at Oak Ridge National Laboratory. Signal averaging has been carried out in accordance with the π/2-sector technique by gating the detection of scattered intensity in synchronism with the sample strain. In-phase and out-of-phase intensity changes have been observed for a high-density polyethylene at various frequencies (0.05–3.2 Hz) and temperatures (0–70°C). Changes are greatest at small scattering angles. Frequency dependence is greatest at lower temperatures, indicating a time-dependent response of the structural changes leading to scattering at these temperatures. The behavior is not pronounced at elevated temperatures. The similarity of the scattering at both azimuthal angles of 0° and 90° suggests the existence of an additional mechanism, perhaps microvoid formation. To evaluate void contribution, the dynamic invariant function is determined as a function of frequency and temperature. It appears that the microvoid formation lags behind the applied strain. The static and swelling SAXS studies present further evidence of void generation during elongation.     

Oxygen permeability of novel organic-inorganic coatings: I. Effects of organic-inorganic ratio and molecular weight of the organic component

The oxygen barrier properties of composite materials, consisting of a 45 μm thick LDPE substrate coated by a thin layer (0.7-1 μm) of new hybrid organic-inorganic materials based on SiO₂ and PE-PEG block copolymers, have been characterized at 35 and 50 °C. A significant decrease (25-40%) of the oxygen transfer rate has been observed for coated samples with respect to bare substrate both at 35 and 50 °C. The effects on the coating permeability of organic-inorganic ratio, molecular weight of the PE-PEG block copolymers and temperature are discussed.