功能性聚丙烯酰胺类微球的制备及应用

介绍了功能性聚丙烯酰胺类微球的各种制备方法,主要为分散聚合法和无皂乳液聚合法。其中重点介绍了改进的无皂乳液聚合法-超声波无皂乳液聚合法、紫外光引发无皂乳液聚合法和微波加热无皂乳液聚合法;同时,还介绍了功能性聚丙烯酰胺类微球的种类和应用,诸如:温敏性聚丙烯酰胺微球、磁性聚丙烯酰胺微球、pH值响应聚丙烯酰胺类微球以及聚丙烯酰胺与无机微粒形成的复合微球。并对功能性聚丙烯酰胺类微球研究作了展望。     

Optical properties of electrochemically deposited ZnO thin films on colloidal crystal film of SiO2 microspheres

The optical properties of electrochemically deposited ZnO thin films on colloidal crystal film of SiO2 microspheres structures were studied. Colloidal crystal film of SiO2 microspheres were self-assembled by evaporation using SiO2 in solution at a constant 0.1 wt%. ZnO in thin films was then electrochemically deposited on to colloidal crystal film of SiO2 microspheres. During electrochemical deposition, the content of Zn(NO3)2 x 6H2O in solution was 5 wt%, and the process's conditions were varied between of 2-4 V and 30-120 s at room temperature, with subsequent heat-treatment between 200 and 400 degrees C. A smooth surface and uniform thickness of 1.8 microm were obtained at 3 V for 90 s. The highest PL peak intensity was obtained in the ZnO thin film heat-treated at 400 degrees C. The double layered ZnO/SiO2 colloidal crystals showed clearly better emission properties than the SiO2/ZnO and ZnO structures.     

Leaching of water-soluble plasticizers from polymeric films prepared from aqueous colloidal polymer dispersions

The leaching of water-soluble plasticizers from polymeric films prepared by casting and drying of plasticized colloidal polymer dispersions was investigated with respect to the type and concentration of plasticizer (triethyl citrate or triacetin), film thickness, type of colloidal polymer dispersions (acrylic: Eudragit RS30D, RL30D, or L30D; cellulosic: Aquacoat), Eudragit RS30D/RL30D ratio, and method of film preparation (solvent- or pseudolatex-casting). The leaching increased with increasing level of plasticizer as indicated by an increase in the release rate constant while the release rate constant was independent of the film thickness. The leaching was more rapid from Aquacoat films than from Eudragit RS30D films at all plasticizer concentrations. Increasing the amount of the more hydrophilic polymer dispersion, Eudragit RL30D, in mixed Eudragit RS/RL films increased the rate of leaching. The incorporation of propranolol HCl into the polymeric films significantly increased the leaching rate constant when compared to drug-free films. The leaching from pseudolatex-cast films was faster when compared to the leaching from solvent-cast films due to the denser structure of the solvent-cast films.     

Polymer dispersion preparation by flow induced phase inversion emulsification. Part 1 The effect of silica on emulsification and dispersion characteristics

Low density polyethylene (LDPE) melt was emulsified in the presence of a hydrophobically modified water soluble polymer (HMWSP) and colloidal hydrophilic silica using the Flow Induced Phase Inversion (FIPI) emulsification technique. HMWSP was used as the surface active material. After the emulsification, LDPE melt was solidified to obtain a polymeric dispersion. Silica was used to aid the emulsification and improve the emulsion/dispersion characteristics. It was shown that the presence of silica increases the amount of aqueous phase necessary for phase inversion from water-in-LDPE melt to LDPE melt-in-water emulsion. The mean particle size and particle size span increased in the presence of silica. However, due to broader particle size distribution, the viscosity was lowered. The dispersions with silica appeared to form a more uniform film compared with the dispersion without silica. When the silica concentration is less than 1% in aqueous phase, an emulsion is obtained. At 2% silica level, a wet powdery material is obtained. This material can be diluted to obtain a dispersion or it could be used in powder coating.     

无机空心球材料的乳胶粒模板法制备及应用

对高分子乳胶粒模板法制备各种无机材料空心微球的研究进展进行了概述，介绍了空心微球作为新型无机材料在反应工程、光电材料、包覆材料以及新型化学建材等方面的潜在应用。     

One-pot synthesis of HA-coated gelatin microspheres by an emulsion method

A one-pot strategy was firstly presented in this paper to prepare gelatin-hydroxyapatite (HA) composite microspheres with a core-shell structure in an inverse emulsion. The FT-IR and XRD analysis confirmed the unique formation of HA on the surface of the gelatin microspheres. The deposited HA particles of about 50 nm in size were found to be approximately spherical in morphology and poorly crystallized. When the weight ratio of HA to gelatin was less than 1:4, most of the HA particles were precipitated on the surface of the gelatin spheres to form a homogeneous coating of about 100 nm in thickness. Moreover, the resulting core-shell composite microspheres had a good dispersity and displayed a particle size distribution of 5-40 μm.     

Fe_3O_4/聚苯乙烯磁性复合微球的制备与应用前景

采用改进的乳液聚合法,制备了磁性Fe3O4为核、苯乙烯和丙烯酸的共聚物为壳的磁性高分子复合微球。在透射电镜下观察磁性微球的粒径在130 nm左右;并用FT-IR、XPS和热失重方法表征了复合微球的组成成分、羧基(-COOH)的含量及所含Fe3O4的百分量。结果表明,微球的粒径分布均匀,大小可控,稳定性好,具有一定的抗溶剂性能,可长时间存放,是纳米磁性高分子聚合物网络的雏形。     

Leaching of water-soluble plasticizers from polymeric films prepared from aqueous colloidal polymer dispersions

Abstract

The leaching of water-soluble plasticizers from polymeric films prepared by casting and drying of plasticized colloidal polymer dispersions was investigated with respect to the type and concentration of plasticizer (triethyl citrate or triacetin), film thickness, type of colloidal polymer dispersions (acrylic: Eudragit RS30D, RL30D, or L30D; cellulosic: Aquacoat), Eudragit RS30D/RL30D ratio, and method of film preparation (solvent- or pseudolatex-casting). The leaching increased with increasing level of plasticizer as indicated by an increase in the release rate constant while the release rate constant was independent of the film thickness. The leaching was more rapid from Aquacoat films than from Eudragit RS30D films at all plasticizer concentrations. Increasing the amount of the more hydrophilic polymer dispersion, Eudragit RL30D, in mixed Eudragit RS/RL films increased the rate of leaching. The incorporation of propranolol HCl into the polymeric films significantly increased the leaching rate constant when compared to drug-free films. The leaching from pseudolatex-cast films was faster when compared to the leaching from solvent-cast films due to the denser structure of the solvent-cast films.     

Microencapsulation of a hydrophilic drug into a hydrophobic matrix using a salting-out procedure. II. Effects of adsorbents on microsphere properties

Wax microspheres of the hydrophilic drug guaifenesin were prepared by the congealable disperse-phase method using a salting-out procedure. In order to improve the particle properties of the microspheres, adsorbents (colloidal silica, magnesium stearate, and talc) were used during preparation. The effects of adsorbents on microsphere properties such as the angle of repose (AR), compressibility index (CI), geometric mean diameter (GMD), loading efficiency (LE), and in vitro drug release (DR) were determined. The AR, CI, and GMD of the microspheres were significantly reduced in the presence of the adsorbents. Increase in the concentrations of colloidal silica and magnesium stearate led to lower LE and faster DR, while talc showed no effect, which could be due to the particle diameter and specific surface area of the adsorbents. The microspheres prepared with colloidal silica were chosen to be compressed into tablets since they were smaller, more uniform, and had better flow properties than those made with magnesium stearate and talc. The in vitro drug release profile of the microsphere tablets was compared with that of commercially available Mucinex®, sustained release guaifenesin matrix tablets. Similar release profiles were observed between the two tablets. Scanning electronic microscopy (SEM) studies of the broken tablets revealed that the deformation of the microspheres caused by compression was minimal.     

聚苯乙烯蓝色胶体晶体膜的制备工艺

本文以单分散的粒径为340±10nm的聚苯乙烯微球为原料,采用垂直自组装法制备了蓝色聚苯乙烯胶体晶体膜。研究了乳液浓度、干燥温度、组装容积等因素对聚苯乙烯胶体晶体膜的微观形貌和呈色性能的影响。结果表明:当乳液浓度较小时,微球呈现单层均匀分布,局部发生自组装,当乳液浓度达到0.1wt%时,微球呈现多层密排六方排列,宏观上呈现明亮的蓝色。当干燥温度为40℃时,该胶体晶体膜微观形貌为高质量的密排六方结构,呈现均匀明亮的蓝色。对比试验得出,在50mL的容器中,PS微球容易发生自组装且呈现明亮均匀的蓝色。同时发现,该胶体晶体膜在较低强度的光线下呈色比较微弱,蓝色饱和度较低,在强烈的光照下,呈现出绚丽的蓝色。     

Highly ordered large-area colloid templates for nanostructured TiO2 thin film gas sensors

We report a novel process that uses highly ordered colloidal templating to fabricate nanostructured TiO2 thin film gas sensors. An O2 plasma treatment is used to decrease the contact angle of a water droplet on a SiO2/Si substrate from 46 degrees to 3 degrees. The formation of this hydrophilic surface enhances the adhesion of polystyrene microspheres to the substrate during the spin coating of the colloidal solution, leading to a large-area colloid template of closely packed monolayer microspheres on the substrates. Embossed TiO2 thin film gas sensors fabricated through highly ordered colloidal templating using O2 plasma exhibit substantially enhanced gas sensing performance as compared to those without surface treatments prior to colloidal templating.     

Formulation and in vitro evaluation of prolonged release floating microspheres of atenolol using multicompartment dissolution apparatus

The aim of the present work was to prepare floating microspheres of atenolol as prolonged release multiparticulate system and evaluate it using novel multi-compartment dissolution apparatus. Atenolol loaded floating microspheres were prepared by emulsion solvent evaporation method using 3² full factorial design. Formulations F1 to F9 were prepared using two independent variables (polymer ratio and % polyvinyl alcohol) and evaluated for dependent variables (particle size, percentage drug entrapment efficiency and percentage buoyancy). The formulation(F8) with particle size of 329?±?2.69 µm, percentage entrapment efficiency of 61.33% and percentage buoyancy of 96.33% for 12?h was the of optimized formulation (F8). The results of factorial design revealed that the independent variables significantly affected the particle size, percentage drug entrapment efficiency and percentage buoyancy of the microspheres. In vitro drug release study revealed zero order release from F8 (98.33% in 12?h). SEM revealed the hollow cavity and smooth surface of the hollow microspheres.     

支化丙烯酸酯乳液的制备和性能

目的研究支化单体对丙烯酸酯乳液的影响。方法以顺丁烯二酸酐和季戊四醇为原料,通过酯化反应制备聚酯型四臂支化单体,将其水分散液与甲基丙烯酸甲酯等单体进行乳液聚合,得到支化丙烯酸酯乳液。测定不同比例分散液对乳液基本性能的影响。结果制备乳液粒径分布100~200 nm,表面张力稳定在30~35 m N/m,增加分散液的比例可适当降低乳液粘度,降低吸水率。结论将支化聚合物引入乳液聚合体系,可有效降低乳液粘度和吸水率。     

Prolonged Release of Tegafur from S/O/W Multiple Emulsion

Abstract

To develop a prolonged and sustained release preparation, we prepared an albumin microsphere-in-oil-in-water emulsion (S/O/W) and examined sustained release from it in comparison with other control preparations such as water-in-oil (W/O) emulsions and microspheres in vitro and in vivo, respectively. Tegafur was used as a model drug. A microsphere-in-oil emulsion was prepared by adding albumin microspheres to soybean oil containing 20% Span 80. To prepare an S/O/W emulsion, the microsphere-in-oil emulsion was added into an aqueous solution of hydroxypropyl methylcellulose containing Pluronic F68. The mean particle size of the albumin microspheres was 3 µm, and the ratio of entrapment of tegafur into albumin microspheres was about 25%. In an in vitro release test, the t₇₅ of the S/O/W emulsion was fourfold greater and in an in vivo release test the mean residence time of tegafur from the S/O/W emulsion was more than twofold that from a W/O emulsion or microsphere system. The mean residence time of 5-fluorouracil (5-FU) from an S/O/W emulsion was also greater than with other dosage forms. These results suggest the possible usefulness of an S/O/W emulsion for the sustained and prolonged release of tegafur.     

水性油墨用丙烯酸酯乳液的制备及应用

目的研究塑料包装薄膜印刷水性油墨用丙烯酸酯乳液的制备工艺。方法选用可聚合乳化剂,通过种子乳液聚合制备丙烯酸酯乳液,采用傅里叶变换红外光谱仪(FT-IR)、差示扫描量热仪(DSC)对乳液聚合产物进行了表征。结果采用适宜的可聚合乳化剂复配,以及引入单体甲基丙烯酸缩水甘油酯均可提高涂膜的耐水性。改变甲基丙烯酸甲酯、苯乙烯(硬单体)与丙烯酸丁酯(软单体)的比例,可以调整乳液涂膜的耐水性和附着力。结论当乳化剂质量分数为单体量的2.5%,软硬单体质量比为1∶1,甲基丙烯酸缩水甘油酯质量分数为单体量的8%时,所得乳液涂膜以及该乳液配制的油墨在聚酯薄膜上均具有良好的附着力、耐水性。     

Effect of concentration and temperature on the properties of the microspheres prepared using an emulsion–solvent extraction process

Methylaluminoaxane (MAO) microspheres of average size smaller than 100 μm were prepared using a solvent extraction process; excess of perfluorocarbon (PFC) was added to the hydrocarbon-in-perfluorocarbon emulsion to solidify the MAO droplets. The effect of the MAO concentration in the dispersed phase, the temperature of the PFC added to the emulsion and the preparation temperature on the size, the size distribution and the morphology of the MAO microspheres was studied. MAO droplets broke up more easily with decreasing dispersed phase viscosity and hence the size of the MAO microspheres decreased. The temperature of the PFC added to the emulsion did not significantly affect the size and the morphology of the MAO microspheres. The size of the MAO microspheres increased with increasing preparation temperature. The main reason for the increased size of the MAO microspheres was the increased coalescence with increasing preparation temperature. In addition the porosity of the MAO microspheres increased with increasing preparation temperature.     

A novel emulsifier-free emulsion route to synthesize ZnS hollow microspheres

ZnS hollow microspheres were prepared via a novel emulsifier-free emulsion route for the first time. The aqueous solution of zinc nitrate and the toluene solution of thioacetamide were emulsified under sonication to form water in toluene emulsion, and then the emulsion was processed at elevated temperature under sonication for 45 min, by which ZnS nanoparticles were generated and assembled spontaneously at the surface of water droplets; after the subsequent separation, wash and desiccation process, ZnS hollow microspheres were obtained. ZnS hollow microspheres were characterized by TEM, XRD, UV-vis and particle size analyzer; the effect of the reaction temperature on the products was investigated. The results showed that ZnS hollow microspheres were made up of ZnS nanoparticles and had cubic structures (β-ZnS); with the rise of reaction temperature, the ZnS hollow microspheres became smaller and more compact. This study provided a promising route for the preparation of a variety of hollow microspheres.     

DNA-assisted binding of microspheres on glass substrates and their laser-induced release

DNA hybridization has been increasingly adopted in materials sciences due to its complementary nature of single stranded DNAs. This unique property could be potentially used in the realization of 2 dimensional (2D) arrays of colloidal microspheres as a precursor to further build more complicated superstructures. In order to precisely understand this DNA-assisted assembly of colloidal particles, we quantitatively assessed the surface density of grafted and hybridizing accessible DNA oligomers on both substrate and colloidal particles. The DNA grafting densities were determined by UV–Vis of dye-functionalized complementary DNA oligomers, in conjunction with theoretical models. The variations of the concentration of hybridized DNA as a function of parameters such as the number of DNA base pairs (bp), the length of spacer and the size of sphere were also investigated to determine the immobilization strength of colloidal microspheres on the substrate. Dehybridization of the particle was conducted by utilizing a focused laser beam. These results were also compared with the particle hybridization energies and modeled according to the sum of DNA bindings as a function of the number of hybridized bases.     

Ketoprofen Spray-dried Microspheres Based on Eudragit® RS and RL: Study of the Manufacturing Parameters

The preparation of ketoprofen spray-dried microspheres can be affected by the long drug recrystallization time. Polymer type and drug–polymer ratio as well as manufacturing parameters affect the preparation. The purpose of this work was to evaluate the possibility to obtain ketoprofen spray-dried microspheres using the Eudragit® RS and RL; the influence of the spray-drying parameters on morphology, dimension, and physical stability of microspheres was studied. Ketoprofen microspheres based on Eudragit® blend can be prepared by spray-drying and the nebulization parameters do not influence significantly particle properties; nevertheless, they can be affected by drying and storage methods. No effect of the container material is found.     

Monolayer polystyrene micro-spheres array master derived by spin-coating method for UV nanoimprint

Polystyrene micro-spheres aqueous suspensions were obtained by an emulsifier-free polymerization method. Fourier transform infrared spectroscopy and laser particle size distribution were used to characterize the colloidal solutions. Results indicate that the polystyrene micro-spheres colloidal solution has a good dispersion and the micro-spheres have a uniform size and smooth surface. The as-prepared polystyrene micro-spheres colloidal solution was spun onto glass substrates and then the coated sample was heated at 70 degrees C for 1 h to form close-packed monolayer polystyrene microspheres arrays, which are used as a master. Scanning electron microscopy was used to observe the morphological properties of the polystyrene micro-spheres array. A relative good result can be easily obtained by a spinning speed of 2000 rpm for 30 second, when the solution concentration is around 10 wt.%. Furthermore, the polydimethylsiloxane soft mold was replicated from the-fabricated polystyrene micro-spheres array master and was then imprinted onto the photosensitive hybrid film under UV-irradiation and thus the micro-lens arrays built in the photosensitive hybrid sol-gel film were obtained.