新型含有机硅二元多嵌段共聚物的研究

报道了聚羟基醚（ＰＨＥ）、聚羟基醚砜（ＰＨＥＳ）、酚酞聚羟基醚（ＰＰＨＥ）和聚对羟基苯乙烯（ＰＨＳ）与端胺基聚二甲基硅氧烷（ＰＤＭＳ）通过羟胺缩合生成ＡＢｍｎ新型结构的可溶性含有机硅二元多嵌段共聚物，ｍ值在１～６之间，详细讨论了反应物浓度对共缩聚反应的影响，并通过分子量测定、红外光谱分析和动态力学分析（ＤＭＡ）技术初步确定了其反应机理、结构和动态力学性能．     

一种高感度深紫外正性化学增幅型抗蚀剂的制备

聚对羟基苯乙烯和环己基乙烯基醚反应得到缩醛保护的聚合物.该聚合物易溶于常见的有机溶剂,具有较好的热稳定性,在248 nm处透明性良好.该聚合物可与聚对羟基苯乙烯-甲基丙烯酸金刚烷基酯及二砜光产酸剂等组成一种三组分正性化学增幅型深紫外光致抗蚀剂,初步研究了该抗蚀剂的感光成像性能.采用KrF激光（248 nm）曝光,在较低的后烘温度下,显影得到分辨率为180 nm的线条图形.显影后的留膜率在99%以上.在光致抗蚀剂体系中引入对羟基苯乙烯-金刚烷基甲基丙烯酸酯共聚物,可提高光刻胶材料的玻璃化转变温度,有利于其实际应用.     

嵌段-接枝共聚物SEPG与PS(OH)之间的氢键络合导致胶束化的研究

利用原子转移自由基聚合反应合成了以聚苯乙烯-b-聚(乙烯-co-丙烯)(SEP)为主链、无规分布且数目可控的聚甲基丙烯酸乙酯(PEMA)为支链的嵌段接枝共聚物SEPG.发现在甲苯中因支链PEMA与聚(苯乙烯-co-对六氟羟丙基-α-甲基苯乙烯)[简称PS(OH]的氢键络合作用和EP嵌段的溶解作用导致了聚集体的胶束化.研究了胶束的尺寸及其分布对PS(OH)中羟基含量和共混物组成的依赖性.     

一种248 nm光刻胶成膜树脂的合成及相关性能研究

通过自由基共聚合,制备了前驱体共聚物聚对特丁氧酰氧基苯乙烯-共-N-羟基-5-降冰片烯-2,3-二甲酰亚胺甲基丙烯酸酯,该共聚物可以通过热解而部分脱除酚羟基上的保护基,得到目标共聚物聚对羟基苯乙烯-共-N-羟基-5-降冰片烯-2,3-二甲酰亚胺甲基丙烯酸酯-共-对特丁氧酰氧基苯乙烯.通过对具有合适分子量的目标共聚物的有机溶剂溶解性、热性能、成膜性、抗干蚀刻能力和在248 nm处光学吸收(为0.212 μm^-1)性能进行研究,表明该聚合物能满足248 nm光刻胶成膜树脂的要求;此外,目标共聚物还具有酸致脱保性能.具有合适分子量和脱保率的目标共聚物,通过对其酸解留膜率的测试,推测其可能满足248 nm光刻胶的曝光显影工艺过程.     

含有机硅三元多嵌段共聚物的研究──Ⅲ．不同硬段、半硬段对含有机硅三元多嵌段共聚物性能的影响

以双酚Ａ聚砜或酚酞作为硬段，聚对羟基苯乙烯、酚醛、聚羟基醚或聚羟基醚砜作为半硬段，聚二甲基硅氧烷作为软段合成了七种三元多嵌段共聚物，并对其稳定性、动态力学性能进行了比较详细的研究。结果表明这类共聚物在溶液中的稳定性及热稳定性主要与半硬段有关；它们的形态结构同属于微相分离，并在很宽的温度范围内表现出优良的弹性体性质。三元多嵌段共聚物中硬段与半硬段的相容性直接影响其力学性能，当两者的相容性好时，其强度高于对应的二元多嵌段共聚物。     

聚(丙烯腈-对羟基苯乙烯)与聚碳酸酯及聚四甲基双酚-A碳酸酯的相容性研究

在聚 (丙烯腈 苯乙烯 ) [P(S AN) ]中苯乙烯 (S)苯环的对位引入羟基基团获得聚 (丙烯腈 对羟基苯乙烯 ) [P(AN VPh) ],P(AN VPh)与聚碳酸酯 (PC)体系及P(AN VPh)与聚四甲基双酚 A碳酸酯 (TMPC)体系的相容性实验结果表明 ,由于对羟基苯乙烯 (VPh)的引入 ,使体系中同时存在“分子间特殊相互作用”和“分子内排斥性相互作用”两种效应 ,从而使体系的相容性获得改善 .P(AN VPh)共聚物中AN的摩尔百分含量在 12 3%～ 4 9 5 %范围内时 ,P(AN VPh) PC共混物体系为热力学均相体系 ,采用TMPC替代PC与P(AN VPh)共混时 ,共聚物中AN的摩尔百分含量在 0～ 5 8 9mol%范围内TMPC P(AN VPh)共混物体系为热力学相容体系 .通过Flory Huggins平均场理论计算与拟合所获得的相容窗口相图与实验值较为吻合 ,同时获得相互作用参数χTMPC -VPh=- 0 19.     

苯乙烯/马来酸酐共聚物修饰碳纳米管的研究

利用羟基碳纳米管上的羟基与马来酸酐之间的简单反应, 在碳纳米管上引入双键, 进一步引发苯乙烯聚合, 在碳纳米管表面接枝苯乙烯马来酸酐共聚物, 同时采用羟基碳纳米管与苯乙烯马来酸酐共聚物直接反应也在碳纳米管的表面引入了苯乙烯马来酸酐共聚物. 经IR, Raman, TG和TEM测定, 证明了碳纳米管与苯乙烯马来酸酐共聚物之间为化学键连接关系.     

酶促开环聚合与自缩合乙烯基共聚合相结合制取超支化聚合物

在Novozyme 435脂肪酶催化下, 甲基丙烯酸羟乙酯(HEMA)引发己内酯(ε-CL)开环聚合反应, 得到一端为双键, 另一端为羟基的直链聚己内酯(PCL)产物; 将其端羟基官能化得到大分子AB*型单体, 与苯乙烯以原子转移自由基聚合(ATRP)反应形式进行自缩合乙烯基共聚合, 得到超支化结构聚苯乙烯-b-聚己内酯产物.     

248 nm深紫外光刻胶用成膜树脂的研究进展

综述了用于248 nm化学增幅型深紫外光刻胶的不同种类和结构的成膜树脂,以及所使用单体的研发进展,包括聚甲基丙烯酸甲酯及其衍生物、聚对羟基苯乙烯及其衍生物、N取代的马来酰亚胺衍生物,以及其他聚合物等,对不同结构成膜树脂的曝光条件、对光刻胶性能的影响进行了介绍。     

聚丙烯醛及其共聚物的膦化反应

用游离基聚合法将丙烯醛及其它烯类单体制成丙烯醛均聚物、丙烯醛-苯乙烯共聚物及丙烯醛-二乙烯苯共聚物,从其红外光谱图上,知聚丙烯醛具有羰基、羟基、碳—碳双键和大量的醚键,聚丙烯醛与羟氨盐酸盐反应后,红外光谱图不再显示有羰基和醚键;与氢氧化钠反应后,羰基增高与醚键有所下降,这些特征表明:聚丙烯醛的羰基与醚键是活泼的。 不同组成的丙烯醛—苯乙烯共聚物,其红外光谱有差别,苯乙烯含量低的共聚物,羰基波峰小,醚键波峰高,当苯乙烯量增至与丙烯醛的克分子数约相同时,羰基波峰高,醚键波峰小,这表明苯乙烯与丙烯醛共聚后,可减少聚丙烯醛的成环反应,由于这个缘故,苯乙烯—丙烯醛共聚物及二乙烯苯(含量不能过高)—丙烯醛共聚物的膦化程度比丙烯醛的均聚物高,若苯乙烯及二乙烯苯的含量不太大,甚至共聚物的磷含量及交换量也较均聚物高。 将制成的均聚物、共聚物在不同条件下(改变反应时间、反应温度及不同溶剂)与三氯化磷反应,然后用醋酸分解,得到α-羟基二元磷酸,在室温(20℃)反应24小时,可得稳定的磷含量及交换量;温度升高,(不超过75℃)反应速度加快。用高介电常数溶剂及混合溶剂,能得到较高磷含量及交换量的产品。 由于均聚物及共聚物的磷化反应不完全,同时所存在的羰基能起Cannizzaro反应,故磷化物     

（PSF—PDMS—PHS）n／PSF共混物的相容性及表面组成

利用ＤＳＣ、ＤＭＡ、ＴＥＭ和ＸＰＳ对［ＰＳＦ－ＰＤＭＳ－ＰＨＳ］ｎ／ＰＳＦ共混物的相容性及表面组成进行了研究．结果表明，ＰＤＭＳ在共混物表面的富集与ＰＳＦ均聚物和［ＰＳＦ－ＰＤＭＳ－ＰＨＳ］ｎ中硬段的相容性有关；ＰＤＭＳ在相容的共混物体系表面的富集与对应的多嵌段共聚物组成基本相近；不相容共混物体系表面ＰＤＭＳ的富集程度相对较高，当共混物本体中有机硅含量从１％增至５％，表面层ＰＤＭＳ的含量迅速增加，可达到嵌段共聚物中ＰＤＭＳ的含量．     

Formation of intramolecular poly(4-hydroxystyrene) dimer radical cation

Poly(4-hydroxystyrene) (PHS) has been used in lithography as a backbone polymer and is also a promising material for extreme-ultraviolet or electron beam lithography. The dynamics of PHS radical cations generated upon exposure to electron beam were investigated. The transient absorption of PHS was observed in the near-infrared region in p-dioxane solutions by pulse radiolysis. Charge resonance (CR) bands that represent pi-pi interaction between the two chromophores of the intramolecular PHS dimer radical cation were observed, whereas p-cresol shows no distinct CR band. Although the radical cations of phenol derivatives are known to be easily deprotonated, it was found that the dimer radical cation formation leads to less deprotonation by its charge resonance stabilization.     

聚砜、聚二甲基硅氧烷、聚对羟基苯乙烯三元多嵌段共聚物的形态结构

利用动态力学分析（ＤＭＡ）．透射电子显微镜（ＴＥＭ）和小角Ｘ 光光散射（ＳＡＸＳ）对聚砜（ＰＳＦ）、聚二甲基硅氧烷（ＰＤＭＳ）和聚对羟基苯乙烯（ＰＨＳ）三元多嵌段共聚物ＰＳＦ—ＰＤＭＳ—ＰＨＳｎ的形态结构进行了研究．结果表明，ＰＳＦ—ＰＤＭＳ—ＰＨＳｎ的形态结构出现了许多新的现象，除具有微相分离的基本特征外，还出现双连续相双分散相的特征．在适当的嵌段长度和组成下，通过ＴＥＭ观察到一种新的特殊形态 蜂窝状形态结构，并在嵌段共聚物两相界面处直接观察到非常清晰的界面相．同时，对该形态的形成过程作了初步讨论．     

Permeation and separation of styrene/ethylbenzene mixtures through cross-linked poly(hexamethylene sebacate) membranes

Poly(hexamethylene sebacate) (PHS) which has strong affinity for styrene was selected as membrane material, and the characteristics of permeation and separation for the styrene/ethylbenzene mixtures through these PHS cross-linked with N,N,N′,N′-tetraglycidyl m-xylenediamine(TETRA-DX) membrane by pervaporation were investigated. The cross-linked PHS membranes exhibited a styrene permselectivity for the styrene/ethylbenzene mixtures and the permeation rate increased with increasing styrene in the feed solution. The permselectivity of their membranes was strongly governed by the sorption separation process depending on the difference of the solubility between styrene and ethylbenzene. The molecular weight of PHS had also influence to the separation factor and permeation rate in pervaporation.     

Electronic and photophysical properties of selected organic boron-containing molecules: Insight into effects of heteroatom substitution and aggregation

The density functional theory (DFT) and time-dependent DFT methods were used to investigate the electronic and optoelectronic properties of several main group atom-doped polycyclic aromatic hydrocarbons, such as oxygen-substituted PHO1 and PHO2, and sulfur-substituted PHS1 and PHS2. The ground-state structures of these molecules generally have an open-shell singlet configuration with a certain diradical character. In comparison with PHO1 and PHO2, PHS1 and PHS2 own larger diradical character indices due to their increased anti-aromaticity. Although the substitution of sulfur for the peripheral oxygen has a significant effect on the molecular geometry, the adiabatic excitation energy levels of the corresponding low-lying excited states of these molecules are less changed. Calculations reveal that here the intersystem crossing (ISC) and reverse intersystem crossing processes in CH₂Cl₂ mainly occur between the S₁ and T₂ states, and the cis molecules PHO2 and PHS2 have better charge transportation performance. Furthermore, the electronic and photophysical properties of these B-containing molecules are predicted to be tuned by the peripheral atom substitution and the structural and aggregation changes.     

Aliphatic Polyester Blends Based upon Poly(Lactic Acid) and Oligomeric Poly(Hexamethylene Succinate)

Abstract

In an attempt to gain a degree of control over the mechanical and degradation properties of poly(lactic acid) [PLA], large-scale efforts are underway to alter the phase morphology of PLA through chemical and physical modification. Consistent with this theme, our work aims to adjust the molecular architecture of highly amorphous PLA with an increasing concentration of hydroxy-terminated oligomeric poly(hexamethylene succinate) [PHS]. Gel-permeation chromatography (GPC) verifies the enhanced presence of PHS in the blends with a concomitant reduction in number-average molecular weight as the weight fraction of PHS is raised from 0.10 to 0.40. Differential scanning calorimetry (DSC) indicates amorphous phase compatibility between PHS and PLA at weight compositions of 10/90 and 20/80. However, as the amount of PHS approaches 30 and 40 wt%, the PHS exhibits the ability to crystallize independently from the induced PLA crystalline phase. Dynamic mechanical thermal analysis (DMTA) illustrates variable behavior of the materials under tension as a consequence of structural alterations generated by the oligoester. Finally, preliminary results suggest that these alterations may suppress the hydrolytic degradation of PLA.     

Synthesis and preliminary antifungal evaluation of a library of phytosphingolipid analogues

A library of 64 phytosphingolipid analogues resulting from the systematic variation of the C1, C3, C4, and the N-acyl moiety of phytosphingosine (PHS) has been prepared from common scaffolds derived from the chiral pool and Sharpless asymmetric dihydroxylation reactions. Library members have been evaluated as growth inhibitors of the yeast Saccaromyces cerevisiae. In addition, 1-amino-N-pivaloyl PHS analogues were also tested as IPC synthase inhibitors, in comparison with the natural product khafrefungin.     

Miscibility of poly(ε-caprolactone), a semicrystalline polymer,with amorphous poly(styrene-4-hydroxystyrene) copolymers

The miscibility of poly(ε caprolactone) (PCL) with poly(styrene-co-4-hydroxystyrene) (PHS) copolymers was investigated as a function of comonomer composition experimentally and with calculations by two models; the binary interaction model and the association model. PCL was found to be completely miscible with PHS copolymers containing 5 or more mole percent of 4-hydroxystyrene (HS) comonomer units for the entire range of blend compositions. Segmental interaction densities, B_ijs, were determined by the analysis of the equilibrium melting point depression and by the application of the binary interaction model. By correlating the segmental interaction energy densities with the binary interaction model, thermodynamic miscibility is for comonomer composition over five mole percent of 4-hydroxystyrene, which is in agreement with the experimental phase behavior. Application of the association model for specific interactions to blends also predicts the experimental miscibility boundary and phase behavior for all the PHS copolymers/PCL blends. © 1995 John Wiley & Sons, Inc.     

Surface modification of polystyrene by blending substituted styrene copolymers

The surface modification of polystyrene (PS) by the blending of 4‐acetoxystyrene polymers and their corresponding hydrolysis products, 4‐hydroxystyrene polymers, was investigated on the basis of X‐ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), and contact‐angle measurements. According to XPS and AFM measurements, when polystyrene‐block‐poly(4‐acetoxystyrene) (PS‐b‐PAS) or polystyrene‐block‐poly(4‐hydroxystyrene) (PS‐b‐PHS) was incorporated into PS, the block copolymer was preferentially segregated at the highest surface region of the blend. This segregation increased to a plateau value when more than 5 wt % of either PS‐b‐PHS or PS‐b‐PAS was added. The contact angle of the modified PS by PS‐b‐PAS or PS‐b‐PHS was slightly lower than that of homopolystyrene, but no further decrease was observed with the blend ratio of the diblock copolymer increasing from 5 to 20 wt %. For a PS/PS‐b‐PHS blend, the surface atomic concentration ratio O/C increased linearly with the molecular weight of poly(4‐hydroxystyrene) blocks in diblock copolymer PS‐b‐PHS in the range of our study. The different structures of 4‐acetoxystyrene polymers and their hydrazinolyzed materials may affect the surface compositions of their blends with PS; among these polymers, PS‐b‐PHS and PS‐b‐PAS appeared to be most effective. © 2001 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 39: 1046–1054, 2001     

Refinement of the primary hydration shell model for molecular dynamics simulations of large proteins

A realistic representation of water molecules is important in molecular dynamics simulation of proteins. However, the standard method of solvating biomolecules, that is, immersing them in a box of water with periodic boundary conditions, is computationally expensive. The primary hydration shell (PHS) method, developed more than a decade ago and implemented in CHARMM, uses only a thin shell of water around the system of interest, and so greatly reduces the computational cost of simulations. Applying the PHS method, especially to larger proteins, revealed that further optimization and a partial reworking was required and here we present several improvements to its performance. The model is applied to systems with different sizes, and both water and protein behaviors are compared with those observed in standard simulations with periodic boundary conditions and, in some cases, with experimental data. The advantages of the modified PHS method over its original implementation are clearly apparent when it is applied to simulating the 82 kDa protein Malate Synthase G. © 2009 Wiley Periodicals, Inc. J Comput Chem 2009