LADDER SUPERSTRUCTURE-DIRECTED SYNTHESIS OF A WELL-DEFINED m-PHENELENEDIIMINO-BRIDGED LADDER POLYMETHYLSILOXANE

A well-defined m-phenylenediimino-bridged ladder polymethylsiloxane(LP) was first synthesized through a welldefined ladder superstructure(LS) acting as synthetic template,which was self-assembled by concerted interaction of hydrogen bonding and aromaticπ-πstacking of the monomer(M),N,N'-bis(phenyldichlorosilyl)-m-phenylenediamine.Some key characterization data of LP and,in particular,the extremely vulnerable LS with very unstable Si-Cl and Si-N groups were given.The molecular weights(M_n) of LS and LP are 5...

H-bonding template-directed synthesis of a complete m-PDA-bridged ladder polyhydrosiloxane (OLPHS)

A highly ordered m-phenylenediimino-bridged ladder polyhydrosiloxane （abbr. OLPHS） with Mn = 1.24 × 10^4 was synthesized stoichiometric hydrolysis and dehydrochlorination condensation reaction between Si-Cl and Si-OH bonds. The complete ladder structure of OLPHS has been confirmed by the following three data. Two characteristic Bragg＇s peaks representing the ladder width （w = 0.94 nm） and ladder thickness （t = 0.42 nm） were observed in XRD analysis, which are consistent with those calculated by molecular simulation. The very sharp absorption with a small half-peak width （w1/2 = 0.5 ppm） for [（-HN）HSiO2/2]n moiety of OLPHS in ^29Si NMR spectrum indicated presence of the complete ladder structure. As collateral evidence, a higher glass transition temperature （Tg = 105 ℃） is also recorded in the DSC measurement, implying the high stiffness of ladder chain of OLPHS.

ARCHITECTURE OF LADDER,TUBULAR AND SIEVE-PLATE POLYMERS PREPARED BY STEPWISE COUPLING POLYMERIZATION

'Stepwise-coupling polymerization' (SCP) is a very useful approach for preparing microstructure-controllable ordered network polymers, including soluble one-dimensional ladderlike polymers (LP) and tubular polymers (TP), and two-dimensional sieve-plate polymers. The novel reactive LPs are important precursors of micro-structure controllable polymers such as 'fishbone-' or 'rowboat-' like mesomorphic polymers and their metal complexes as well as tubular polymers (TPs). They are full of great potential for use as advanced materials.

Progress in the Supramolecular Architecture-directed Synthesis of Perfect Ladder Polysiloxanes

1 Introduction Ladder polysiloxanes (LPSs) including organo-bridged ladder polyorganosiloxanes (R-OLPSs, R is side group) and ladder polyorganosilsesquioxanes (R-LPSQs) have intrigued polymer chemists for about 50 years due to their excellent resistance to all kinds of degradations. However, their synthesis has been a great challenge to polymer chemists. Here, we describe a new approach based on supramolecular concerted interactions as follows.2 Results2.1 Synthesis of Perfect R-OLPSsA series of real ...

一种含苯并菲侧基的“毛-棒”状梯形聚倍半硅氧烷LB膜研究(英文)

一种新的含烷基取代的苯并菲侧基的"毛-棒"状(hairy-rod)梯形聚倍半硅氧烷(LPSQ)可以在空气-水界面形成稳定的单分子层,研究了温度、铺展溶剂和浓度对π-A等温曲线的影响.在适当的表面压下,以甲苯为铺展溶剂该单分子层可以被成功地转移至疏水的硅片或石英片上形成均一稳定的Y-型LB膜,其紫外吸收强度在几个月内均保持不变,说明该LB膜具有良好的稳定性,AFM图像表明其形成了均一致密的膜.通过偏振紫外光谱和荧光光谱研究了其面内各向异性,发现LPSQ的分子链采取了平行于拉膜方向的优先取向,最优取向因子S为0.42.

用光谱法研究新型横挂复合光敏基团的梯形 聚倍半硅氧烷液晶定向膜的光致取向行为

我们制备了一种以梯形聚倍半硅氧烷为基材的新型液晶光致定向膜。在膜材料分子设计中,引入横挂型复合光敏基团,提高了光反应效率。利用肉桂酸酯和取代偶氮苯基团的协同光反应,得到了均匀稳定的液晶倾斜沿面定向排列,其预倾角达到5.85°。用紫外二色性和付里埃红外等光谱方法,对其光致取向行为进行了研究。

制备条件对梯形聚硅氧烷取向层光取向行为的影响

选用侧链含有双元光敏基团的梯形聚硅氧烷材料作为光取向材料,采用偏光显微镜(POM)及晶体旋转法,研究了梯形聚硅氧烷光取向层的制备条件,包括取向剂浓度、紫外光辐照度及光照时间对光取向层的取向行为的影响.结果表明,取向剂浓度越大,光敏基团更易于组装成垂直取向状态,进而诱导液晶分子形成垂直取向的分子排列方式.在一定的紫外光辐照度范围内可以有效地引起偶氮苯光敏基团的面内、面外异构化及再取向,有利于取向层诱导液晶分子形成平面取向的分子排列方式.紫外光光照时间的增加有利于取向层诱导液晶分子形成平面取向的分子排列方式.

梯形聚硅氧烷的研究进展

梯形聚硅氧烷(R-LPS)因其独特的双链或多重链结构而具有较单链聚硅氧烷更高的耐热、耐氧化、耐辐射性以及良好的生物稳定性。自从上世纪60年代R-LPS首次被报道以来,一直受到广泛的关注。随着人们对分子间弱相互作用认识的加深,对R-LPS的形成机理、制备方法和性能的研究,都有进一步的发展,并涉及超分子自组装、化学合成、纳米结构及性能表征等许多高分子科学的前沿问题。本文根据近五年来采用"超分子构筑调控逐步偶联和聚合"方法合成的新型双链、三重链及四重链梯形聚硅氧烷及其性能进行了综述,其中包括具有不同侧基的R-LPS的合成与表征。