改性聚苯乙烯微球的制备及其胶体晶体的组装

采用甲基丙烯酸改性的无皂乳液聚合方法制备了尺寸为210 nm、含羧基的聚苯乙烯(PS)微球，用红外光谱、透射电子显微镜和粒度分析仪对其形状和结构进行分析，结果表明，经甲基丙烯酸改性后得到了表面为高密度电荷的单分散性PS微球.用垂直沉积法快速制备出在较大范围(大于1 cm2)呈现很好有序性的密排结构聚苯乙烯胶体晶体薄膜，其在590 nm波长处存在光子带隙.在电子显微镜下，观察到这种胶体晶体是面心立方(fcc)密排结构.     

聚合结晶化胶体阵列结构的压敏光响应性质

制备了由单分散聚苯乙烯微球构成的结晶化胶体阵列结构, 并制备了结晶化胶体阵列聚丙烯酰胺水凝胶薄膜. 通过微区反射光谱研究了其光子带隙位置随外加压力的变化规律. 实验结果表明, 该薄膜在垂直表面方向存在光子带隙, 并在一定载荷范围内带隙波长随外加压力呈可逆线性变化.     

侧链偶氮聚电解质在胶体微球表面的静电层层自组装和微胶囊制作

将侧链偶氮聚电解质应用于聚苯乙烯胶体微球表面的静电层层自组装,得到了偶氮聚电解质和聚二烯丙基二甲基氯化铵多层膜覆盖的核壳微球.实验表明,组装后偶氮苯基团发生了一定程度的解聚集,得到的胶体微球可表现出明显的光色效应.研究进一步采用含肉桂酸酯的光敏聚电解质作为交联的保护壳层,并通过光交联反应使表面层发生交联固化反应.将上述具有核壳结构的胶体球溶解去除聚苯乙烯内核后,得到了含光响应聚电解质的空心微胶囊.     

溶剂散逸自组装制备高分子有序微透镜阵列

利用水珠为模板制备了聚苯乙烯有序多孔膜.在溶剂挥发的制冷作用下,水珠能够在冷的高分子溶液表面凝结形成有序的阵列,溶剂蒸发完毕后,高分子材料按照水珠排列形貌空隙形成有序多孔膜,一种两性共聚物被加入到溶液中稳定水珠而获得有序的多孔结构. 将聚乙烯醇水溶液填充入多孔膜中,蒸干后用氯仿洗去聚苯乙烯,得到聚乙烯醇的整球微透镜阵列. 聚苯乙烯有序针垫阵列是由有序多孔膜撕掉上层制备的,这种针垫结构内部具有半球结构的空间,并以此为模板制备了聚乙烯醇半球微透镜阵列. 2种微透镜阵列均具有微观显影功能. 通过2种微透镜的显像对比证实,半球微透镜阵列比整球微透镜阵列具有更为清晰的多重显像效果.     

聚苯乙烯-co-聚(2,3,4,5,6-五氟苯乙烯)共聚物: 合成及其多孔薄膜的制备

利用原子转移自由基聚合(ATRP)方法, 分别在三氟甲苯、含氟离子液体以及三氟甲苯/含氟离子液体混合溶剂体系中合成了聚苯乙烯-co-聚(2,3,4,5,6-五氟苯乙烯)(PS-co-PPFS)共聚物, 通过¹H NMR、¹⁹F NMR、元素分析以及凝胶渗透色谱法(GPC)对所得聚合物的分子链结构和组成进行了分析和表征. 随后, 利用静态呼吸图法分别在CS₂, CHCl₃ 和CH₂Cl₂ 中制备了有序多孔薄膜, 用扫描电子显微镜(SEM)观察其表面形貌, 并与利用分子量大小相当的聚苯乙烯均聚物(PS)制备的多孔薄膜进行了对比. 研究结果表明: 在三氟甲苯和含氟离子液体溶剂体系中, 均可利用ATRP 聚合方法获得窄分子量分布的PS-co-PPFS 共聚物(M_n＝5200～7900 g·mol^-1, i>M_w/M_n＝1.12～1.22). 对聚合物薄膜的扫描电子显微镜(SEM)观察和分析显示: 分别以CS₂, CHCl₃ 和CH₂Cl₂ 作为溶剂, 利用静态呼吸图法均可制备出PS-co-PPFS 共聚物多孔薄膜. 然而, 与在CHCl₃ 和CH₂Cl₂ 中制备的PS 均聚物多孔薄膜的表面形貌不同的是, PS-co-PPFS 共聚物多孔薄膜呈现出无序排列、平均孔径大小不同的两种孔结构; 在CHCl₃ 中制备所得薄膜的孔结构有序性相对较好, 两种孔的平均孔径分别为0.75 和0.37 μm.     

静电层层自组装制备聚苯乙烯微球(核)/MCM-41纳米粒子(壳)阶层结构复合微粒

采用聚苯乙烯磺酸钠(PSS)和聚二烯丙基二甲基氯化铵(PDDA)两种聚电解质, 通过静电层层自组装成功地将MCM-41介孔二氧化硅纳米粒子包覆到聚苯乙烯(PS)微球表面. 实验结果表明, 当以尺寸为1.4 μm的PS微球为核时, 包覆了两个聚电解质双层(PDDA/PSS)2的PS(PDDA/PSS)2(PDDA/MCM-41)复合结构微粒与包覆了一个聚电解质双层(PDDA/PSS)的PS(PDDA/PSS)(PDDA/MCM-41)复合结构微粒相比, 复合结构微粒之间的交联程度降低, 但是MCM-41纳米粒子在聚苯乙烯微球表面的包覆都比较松散, 且产物中存在大量杂质. 而当以尺寸为5 μm的聚苯乙烯微球为核时, MCM-41纳米粒子紧密地包覆在聚苯乙烯微球表面, 复合结构微粒之间只有少量桥连物, 且产物中杂质很少.     

聚苯乙烯光子晶体的制备及其在传感中的应用

以基于毛细作用的垂直沉积法将单分散的二氧化硅胶体微球自组装成光子晶体．在二氧化硅光子晶体的多孔结构里填充聚苯乙烯甲苯溶液,经甲苯挥发,通过氢氟酸处理去除二氧化硅模板,制备出精美的聚苯乙烯光子晶体．研究表明：保留了模板有序多孔结构的聚苯乙烯能被用来作为敏感膜,这使得其在基于折射率变化的传感应用中具有潜在的价值．     

一种真孔离子交换树脂微球的制备及其孔结构性能与色谱的应用

以聚苯乙烯甲苯溶液为致孔剂,可以制得孔形较规整,孔径分布较均匀,耐高压(200kg/cm~2左右)的交联聚苯乙烯磺酸型离子交换树脂微球。本文对交联20％苯乙烯—二乙烯苯共聚微球,用不同致孔剂致孔后的性能及其磺化前后孔结构形态的变化,以及在色谱分析上的应用进行了探讨。     

二维胶体晶体异质结构的制备及传感性

制备具有不同粒径和折射率的聚苯乙烯(PS)和聚甲基丙烯酸甲酯(PMMA)微球,采用多次尖端导流法制备多重二维胶体晶体异质结构(2D-CCHs)阵列,在2D-CCHs阵列的间隙处填充丙烯酸类凝胶,再将PS或PMMA模板微球去掉,得到传质速度更快的2D-CCHs反蛋白石凝胶.经扫描电子显微镜证实,所制备的异质结构胶体晶体均为二维结构,且排列较为规整.德拜衍射、反射光谱和结构色分析结果表明,2D-CCHs的光学性质主要是各单层二维胶体晶体阵列独立衍射的叠加.随着p H值由7降低至3,双层2D-CCHs反蛋白石凝胶的德拜衍射环直径均减小了约80 nm,表明2D-CCHs反蛋白石凝胶可应用于化学传感领域.     

成膜溶剂与氟化嵌段共聚物膜的表面富集行为

利用接触角、XPS、SFG、AFM等技术研究了环己酮、甲苯和三氟甲苯为成膜溶剂所得聚甲基丙烯酸甲酯-b-聚（甲基丙烯酸-2-全氟辛基乙酯）（PMMA—b—PFMA）嵌段共聚物膜的表面结构与性能．发现浇铸成膜时成膜溶剂对聚合物氟化组分向表面富集程度的影响相对较小,而旋涂成膜时溶剂的影响很大．不管以何种形式成膜,三氟甲苯溶剂最有利于氟化组分向表面富集,甲苯次之,环己酮最差．这一现象与溶剂的挥发速度无关．聚合物在溶液中的聚集结构、气／液界面结构是造成成膜方式对聚合物表面结构与性能产生巨大影响的主要原因．当聚合物在溶液中形成以PFMA为核、PMMA为冠的胶束结构时,在溶液固化过程中氟化组分向表面富集需要较长的时间,这时由于成膜方法直接影响溶液的固化速度,造成其对氟化组分向表面富集的程度影响很大．当聚合物在溶液中以单分子或松散聚集体存在,在溶液固化过程中氟化组分向表面富集的速度很快,这时成膜方法对氟化组分向表面富集的程度影响很小．以上结果无论对理论研究还是应用研究都具有重要意义．     

ESR spin-label study of poly(styrene-co-methacrylic acid)/poly(epsilon-caprolactone) semi-interpenetrating polymer networks with controlled hydrogen-bond interactions

The morphology and miscibility of semi-interpenetrating polymer networks (semi-IPN) prepared with poly(styrene-co-methacrylic acid) [P(S-co-MAA)] of different carboxylic acid contents and poly(epsilon-caprolactone) (PCL) have been studied by ESR spin-label method. The ESR spectra of spin-labeled PCL showed one motional component at any specific temperature. It indicated that the spin-labeled molecules were located in one type of environment. The coexistence of two motional components in the ESR spectra of all semi-IPN samples was observed over a certain temperature range. This phenomenon suggested that the semi-IPNs were not compatible systems; they contained two microphases, a PCL-rich microdomain and a P(S-co-MAA)-rich microdomain. The miscibility could be improved by increasing the carboxylic acid content, which could enhance the hydrogen-bonding interactions between the ester groups of PCL and carboxylic acid groups in P(S-co-MAA). It was also found that the intracomponent cross-linking of the semi-IPNs was not in favor of the miscibility. The microphase separation occurred in all semi-IPNs, even in the samples having strong hydrogen-bonding interactions. With increasing cross-linking density, the microphase separation became more remarkable.     

Self-assembly of mixtures of block copolymers of poly(styrene-b-acrylic acid) with random copolymers of poly(styrene-co-methacrylic acid)

The effects of the addition of random copolymers of poly(styrene-co-methacrylic acid) [P(S-co-MAA)] on the self-assembly of block copolymers of poly(styrene-b-acrylic acid) (PS-b-PAA) are described. The effects of variation of five factors, including the MAA content, the weight fraction and molar mass of the P(S-co-MAA), the initial concentration of the mixture, and the length of the PAA segment in the block copolymer, were investigated. With increasing MAA content, the localization of the random copolymer in the aggregate changed from the core to the interface, which led to a morphological transition from spheres to vesicles. Vesicles, mixtures of vesicles and large spheres, and large spheres alone were formed with increasing weight fraction of the random copolymer. When the molar mass of the random copolymer was high, both rods and vesicles were observed at low water contents; otherwise, only vesicles were observed. The vesicle size increased (from 100 to 140 nm) with increasing initial polymer concentration, whereas the vesicle membrane thickness remained constant. The size of the vesicles prepared from the mixtures increased with water content but decreased with the length of PAA in the diblock.     

PS colloidal particles stabilized by graphene oxide

Exfoliated graphene oxide (GO) sheets with hydrophilic functional groups on the surface were prepared by the oxidation of graphite. Because of the hydrophilic groups on the sheets and the hydrophobic carbon surface, GO sheets were located at the oil-water interface and could be used as a stabilizer in Pickering emulsions. After the Pickering emulsion polymerization of styrene, PS colloidal particles with GO sheets on the surface were prepared. The size of the GO sheets exerts an important influence on the preparation of PS colloidal particles. Small GO sheets located at the liquid-liquid interface and GO-stabilized PS colloidal particles were prepared; however, for large GO sheets, smaller PS colloidal particles prepared on the GO surface were observed. Transmission electron microscopy (TEM), scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS) were used to characterize the structure and morphology of the colloidal particles. TEM, SEM, and XPS results all suggest the successful preparation of GO-stabilized PS colloidal particles.     

双亲性无规共聚物P（VM-co-AMPS）的自组装及其性能

以2-丙烯酰胺基-2-甲基丙磺酸（AMPS）和苯乙烯类光敏单体7-（4-乙烯基苄氧基）-4-甲基香豆素（VM）为共聚单体,采用自由基聚合法制备了光敏性双亲共聚物P（VM-co-AMPS）。P（VM-co-AMPS）在溶剂水中自组装胶束化,用原子力显微镜（AFM）表征了自组装胶体粒子的形态、粒径及其分布。紫外光照使胶体粒子中香豆素基元发生光二聚反应,用紫外-可见光分光光度计（UV-Vis）跟踪其光二聚交联过程,用光学显微镜考察了胶体粒子的乳化性能。结果表明：胶体粒子具有较好的紫外吸收性能和较好的乳化性能。该胶束制备工艺简单,条件温和,避免了溶剂的使用。     

Analytical scale purification of zirconia colloidal suspension using field programmed sedimentation field flow fractionation

Sedimentation field flow fractionation was used to obtain purified fractions from a polydispersed zirconia colloidal suspension in the potential purpose of optical material hybrid coating. The zirconia particle size ranged from 50/70 nm to 1000 nm. It exhibited a log-Gaussian particle size distribution (in mass or volume) and a 115% polydispersity index (P.I.). Time dependent eluted fractions of the original zirconia colloidal suspension were collected. The particle size distribution of each fraction was determined with scanning electron microscopy and Coulter sub-micron particle sizer (CSPS). These orthogonal techniques generated similar data. From fraction average elution times and granulometry measurements, it was shown that zirconia colloids are eluted according to the Brownian elution mode. The four collected fractions have a Gaussian like distribution and respective average size and polydispersity index of 153 nm (P.I. = 34.7%); 188 nm (P.I. = 27.9%); 228 nm (P.I. = 22.6%), and 276 nm (P.I. = 22.3%). These data demonstrate the strong size selectivity of SdFFF operated with programmed field of exponential profile for sorting particles in the sub-micron range. Using this technique, the analytical production of zirconia of given average size and reduced polydispersity is possible.     

Facile synthesis and characterization of uniform CdS colloidal spheres

Uniform CdS colloidal spheres have been successfully synthesized via a simple hydrothermal method.X-ray diffraction(XRD) analyses indicate that the products exhibit a hexagonal structure.Scanning electron(SEM) and transmission electron microscopy (TEM) are used to characterize CdS colloidal spheres.The final size of the spheres may be selected from a range of 71±2 nm to approximately 181±5 nm by changing the amount of polyvinylpyrrolidone(PVP) and hexamethylenetetramine(HMT).The CdS colloidal spheres are not obtained in the absence of either of the capping agents.A synergistic effect between HMT and PVP is proposed to be crucial for the formation of colloidal spheres.     

The First Structure Determination of Nanosized Colloidal Particles of Pd3P by High-Resolution Electron Microscopy

The exact three-dimensional structure of a nanosized colloidal particle of Pd₃P was determined directly from high-resolution transmission electron microscopy (HRTEM) images that were recorded in several crystallographic directions. An HRTEM image recorded along [011] is shown on the right. The cores of the particles were excluded from the analysis because of severe multiple diffraction.     

Sodium dodecyl benzene sulfonate-catalyzed reaction for aromatic aldehydes with 1-phenyl-3-methyl-5-pyrazolone in aqueous media

Sodium dodecyl benzene sulfonate was successfully used for the tandem Knoevenagel-Michael reaction of aromatic aldehydes with 1-phenyl-3-methyl-5-pyrazolone in water to synthesis of 4, 4′-arkylmethylene-bis(1-phenyl-3-methyl-5-pyrazolones) under mild reaction conditions. Efficient catalytic activity and high selectivity of the catalyst contributed to colloidal particle formation in water. The shape and size of the colloidal aggregates were confirmed by optical microscopy and dynamic light scattering.     

Polystyrene@TiO2 core-shell microsphere colloidal crystals and nonspherical macro-porous materials

High-quality and stable PS@TiO(2) core-shell microsphere colloidal crystals were prepared by electrostatic colloid stabilization combined with two-substrate vertical deposition method. The polyelectrolyte stabilized colloids self-assembled into face-centered cubic arrays with the (111) face perpendicular to the substrate. These colloidal crystals are gifted with high mechanical stability toward the flow of solution. Structure-property correlations were made using scanning electron microscopy and UV-vis-NIR spectroscopy. Optical spectra showed the presence of an L-stopband peak in the photonic band structure. Besides, these PS@TiO(2) colloidal crystals can be used as templates to fabricate the nonspherical macro-porous materials, and complete band gaps can be more easily obtained from such structure than from their spherical counterparts due to their lower symmetries. This work will hold the promise of enhanced photonic band gap materials.     

Colloid surface engineering via deposition of multilayered thin films from polyelectrolyte blend solutions

Multilayer thin films were constructed on polystyrene colloidal particles by depositing alternating layers of poly(allylamine hydrochloride) (PAH) at pH 7.5 and varying composition blends of poly(acrylic acid) (PAA) and poly(styrenesulfonate) (PSS) at pH 3.5. Following the deposition of each layer, microelectrophoresis experiments showed alternating zeta-potentials, suggesting the formation of multilayered films on the particles. Scanning and transmission electron microscopy were used to examine the surface morphology of the colloidal particles, with homogeneous surface coatings apparent for films deposited from PAA/PSS blend solutions containing up to 90 wt % PAA. The colloidal stability of these particles is greater than those coated with individual PAH and PAA layers. In the case of the blend PAA/PSS = 25:75 wt %, up to 20 layers were assembled without compromising the colloidal stability of the dispersion. The results demonstrate that the deposition of layers from PE blend solutions containing a strong and weak PE can be used as a facile method for controlling the surface properties and hence the colloidal stability of core-shell particles, as well as the thickness and morphology of the coatings. Control of these parameters is important for subsequent processing and application of these particles in controlled delivery, photonics, catalytic, and separation applications.