Synthesis and characterisation of poly(distyrylbenzene-block-hexa(ethylene oxide)) and its fluorinated analogue—two new block copolymers and their application in electroluminescent devices

Two new soluble block copolymers are reported in which chromophores and hexa(ethylene oxide) units alternate along the polymer backbone. In polymer 1 the chromophore was the distyrylbenzene unit. The polymer was synthesised via the Wittig reaction and the ionisation potential of 5.4±0.2 eV was measured by cyclic voltammetry and photoelectron spectroscopy. Polymer 1 showed a high solid-state photoluminescence efficiency (34%) and was used to make efficient (0.5 cd/A) light emitting diodes (LEDs). Polymer 1 was also used in light emitting cells; these showed luminescence in reverse bias and a reduced turn-on voltage compared to the LEDs. Polymer 2, in which the chromophore was dodecafluoro-distryrylbenzene, was prepared via the Horner-Wittig reaction and showed an ionisation potential of 6.25±0.15 eV and a solid-state photoluminescence efficiency of 17%. It was used as electron-conducting layer in a LED but failed to give significant electroluminescence. The optical energy gap for both polymers was 3.0 eV.     

水分散有机硅－聚氨酯嵌段共聚物合成性能及应用的研究

合成了水分散有机硅－聚氨酯嵌段共聚物乳液，研究了反应动力学、共聚物的性能及应用．首先由八甲基环四硅氧烷以膨润土为催化剂，醋酐为分子量调节剂合成分子量为端羟基聚硅氧烷齐聚物，再使之与甲苯二异氰酸酯及聚乙醇（ＰＥＧ）于丙酮中反应制得端异氰酸酯基的有机硅－聚氨酯预聚体（ＰＳｉ－ＰＥＵ）．将此预聚体用３－（Ｎ－甲基二乙醇氯化铵）－１，２－环氧丙烷扩链，加水乳化即得阳离子型的有机硅－聚氨酯嵌段共聚物（ＰＳｉ－ＰＵ）水乳液．此种水乳液是一种优良的织物整理剂可用以改善织物的表面性能、吸湿性和永久抗静电效果，同时可提高织物的力学性能和耐磨性能．     

Synthesis and characterization of block-copolymer surfactants with specific interactions with associative thickeners

It has been theorized that, in order to get some positive interaction with the associative thickeners, the surfactants should have, at the end of the hydrophilic sequence, a short hydrophobic group. On the other hand, in order to control the hydrophilic lipophilic balance (HLB), it is wise to use well controlled polymerization procedures to build the block-copolymer. Then, the safer and simplest way to reach such goal is to use the ring-opening living anionic polymerization of butylene oxide (hydrophobic sequence) and then ethylene oxide (hydrophilic sequence); this living block-copolymer is then killed using an alkyl or aryl chloride (or bromide). However, because such surfactants include at the end of the hydrophilic sequence a hydrophobic group, they tend to adopt, when adsorbed onto hydrophobic latex particles, a back-folded conformation. In order to get for them an extended conformation, the hydrophilic sequence should have charges able to repel each other. This was achieved upon preparing block-copolymers of acrylic acid and butylacrylate, using a controlled radical polymerization with reversible addition fragmentation transfer (RAFT) agents, starting with the poly(acrylic acid) (PAA) sequence. Then, the radical fragment coming from the RAFT agent is at the end of the PAA sequence. A few rheological data actually confirm the interest of the concept.     

Synthesis and characterization of side-chain liquid-crystalline block-copolymers containing laterally attached photoluminescent quinquephenyl units via ATRP

A series of novel side-chain liquid-crystalline polymers (SCLCPs) consisting of laterally attached photoluminescent p-quinquephenyl (QQP) pendants with different flexible terminal- and/or side-alkoxy chains were synthesized via atom transfer radical polymerization (ATRP). Homopolymers (HP1-HP3) and block-copolymers (PSP1-PSP3 and PEOP1-PEOP3), where QQP units were copolymerized with styrene or ethylene oxide monomers, possessed the number average molecular weights (M_n) of 8.7-26.0 × 10³ with narrow PDI values of 1.08-1.26. Various characterization techniques of polarized optical microscopy (POM), differential scanning calorimetry (DSC), and X-ray diffraction (XRD) were used to investigate their mesomorphic properties, and all homopolymers and block-copolymers exhibited the nematic phase affected by the flexible terminal- and/or side-alkoxy chains of the conjugated rod-like pendants. In addition, the photophysical properties of these polymers were measured by UV-vis and photoluminescence (PL) spectroscopies, which showed blue PL emissions with rather high fluorescence quantum yields in solutions.