二苯基二甲氧基硅烷单体制备空心微胶囊的模板合成方法研究

制备了直径在700～1500 nm范围内的空心聚硅氧烷微球. 在O/W型聚二苯基硅氧烷微乳模板核上, 加入一定比例的二苯基二甲氧基硅烷(D型官能团)和甲基三甲氧基硅烷(T型官能团)的有机硅单体, 使之围绕在模板核表面聚合交联形成核壳结构的聚硅氧烷微胶囊, 利用合适溶剂溶解透析的方法去除模板核得到空心微胶囊. 通过TEM和AFM测定考察, 讨论了体系的各反应条件对空心微球的形态结构和大小分布的影响.     

聚硅氧烷空心胶囊的制备及Heck偶联催化应用

研究了空心聚硅氧烷纳米胶囊负载的钯复合物的制备。合成了胶囊负载的腈钯复合物并研究了它们在烯烃芳基化Heck偶联反应中的催化性能。在O/W型聚二甲基硅氧烷微乳模板核上,共聚一定比例的4-(三乙氧基硅基)-丁腈和二甲基二甲氧基硅烷的有机硅单体,,然后用溶剂溶解透析的方法去除模板核聚二甲基硅氧烷而得到空心纳米胶囊.与醋酸钯反应后用KBH4还原得到空心聚硅氧烷胶囊负载的钯复合物。TEM,AFM等结果显示空心聚硅氧烷纳米胶囊负载的钯复合物已得到制备。该复合物对Heck反应具有很高的催化活性和立体选择性。     

亚微米级聚苯乙烯/聚硅氧烷核壳粒子的制备及其应用

以乳液聚合制备的聚苯乙烯乳液为种子,加入甲基三甲氧基硅烷(MTMS)水解溶液进行缩聚反应,合成亚微米级聚苯乙烯/聚硅氧烷核壳粒子,并以此作为光散射剂添加至聚甲基丙烯酸甲酯(PMMA)树脂中,制备了光散射材料;考察了亚微米级核壳粒子添加在PMMA树脂中的分散性。结果表明:经过双螺杆剪切作用的挤出加工后,可以实现核壳粒子在PMMA树脂中的良好分散。核壳粒子可以大幅度提高PMMA的雾度,当聚苯乙烯/聚硅氧烷核壳粒子(NS82)的含量为1%时,制得的PMMA样片(厚度为2 mm)的雾度为89%,透光率为69%,有效光散射系数为61%。     

聚苯基硅氧烷/聚丙烯酸酯复合乳液的合成与性能

本文以二苯基二甲氧基硅烷(DPDMS)和γ-甲基丙烯酰氧基丙基三甲氧基硅烷(MAPTMS)合成了具有微交联结构的聚硅氧烷乳液,并以此为种子乳液再与丙烯酸酯类单体聚合,合成了稳定且性能优良的聚硅氧烷/聚丙烯酸酯复合乳液.用激光粒度分析仪、FTIR、DMA等进行了表征.结果表明,硅氧烷被有效的接枝到了聚丙烯酸酯分子链中;硅氧烷的加入,使聚合物的储能模量,损耗模量增大,玻璃化温度提高,加入量为10％时,Tg由50.5℃升高到57.2℃;加入20％的硅氧烷涂膜吸水率由13.8％降低到6.8％.     

Poly(St-co-DMC)/SiO_2杂化及空心杂化纳米粒子的合成及表征

采用无皂乳液聚合法合成了聚(苯乙烯-co-甲基丙烯酰氧乙基三甲基氯化铵)(poly(St-co-DMC))纳米粒子,平均粒径约为100 nm.以此纳米粒子为模板,在接近室温及p H为中性的温和条件下,以四甲氧基硅烷(TMOS)为硅源,合成了poly(St-co-DMC)/Si O2杂化纳米粒子,TEM结果显示该纳米粒子具有明显的核壳结构,Si O2主要沉积在壳层.进一步通过四氢呋喃溶解制备得到具有空心结构的纳米粒子,这种空心结构纳米粒子的FTIR图谱中既有Si O2的信号,也有poly(St-co-DMC)的信号,说明空心纳米粒子的壳层不完全是Si O2,对空心纳米粒子的TGA结果分析计算得到Si O2的含量仅为69.7%,说明纳米粒子的壳层为杂化壳层,并且,这种壳层的厚度随着反应温度的升高、反应时间的延长、TMOS用量的增加及聚合物模板中DMC含量的增加而增大.     

核壳式碳纳米管-萘夫西林分子印迹聚合物的制备及应用

采用溶胶-凝胶的方法,以碳纳米管为载体,萘夫西林(Nafcillin)为模板,无水乙醇为溶剂,氨丙基三乙氧基硅烷(APTES)和苯基三甲氧基硅烷(PTMOS)为双功能单体,四乙氧基硅烷(TEOS)为交联剂,合成核壳结构萘夫西林分子印迹聚合物(CNTs@Naf-MIPs).用透射电子显微镜(TEM)、傅立叶变换红外光谱仪(FT-IR)对萘夫西林分子印迹聚合物的结构、形貌进行了表征;对其吸附性能进行了详细研究,CNTs@NafMIPs对模板分子的吸附符合Langmuir方程,Qmax为9.5 mg/g,KD为56.6 mL/mg.制备的印迹聚合物只需30 min达到吸附平衡,吸附-解吸循环5次后,性能稳定.将其应用于加标5和10 μg/kg萘夫西林的鸡蛋样品的选择性富集,回收率可达61.3％～84.3％,准确性较好.     

核壳结构Boc-氨基酸分子印迹分离介质的研究

将硅胶表面硅羟基与γ-（甲基丙烯酰氧）丙基三甲氧基硅烷反应合成具有CC端基的改性硅胶核,进一步以N-Boc-L-色氨酸为模板分子,采用分子印迹技术在改性后的硅胶表面包覆印迹聚合物,制备出核壳结构氨基酸分子印迹分离介质。这种印迹分离介质对模板N-Boc-L-色氨酸具有良好的吸附性,最大饱和吸附量可达到85.96 mg/...     

细乳液法制备聚硅氧烷-Ag纳米复合微球及其抗菌性

首先以苯乙烯(St)及3-甲基丙烯酰氧基三甲氧基硅烷(MPS)为反应单体,通过细乳液聚合制备表面功能化聚硅氧烷微球,然后利用该微球表面的硅羟基及硅氧烷基团对Ag+的吸附及还原作用原位制备聚硅氧烷-Ag纳米复合微球。采用透射电镜(TEM)、紫外(UV-Vis)、热重分析(TG)及X射线衍射(XRD)等对聚硅氧烷-Ag纳米复合微球的形貌和组成进行了表征。研究表明:改变MPS和硝酸银的用量可调控聚硅氧烷-Ag纳米复合微球的形貌及表面银含量;抗菌实验结果表明,聚硅氧烷-Ag纳米复合微球具有较好的抑菌性。     

单分散功能化聚硅氧烷微球的制备及其应用

采用悬浮聚合法以正硅酸乙酯(TEOS)和γ-甲基丙烯酰氧基丙基三甲氧基硅烷(MPS)为主要原材料,制备表面功能化的单分散聚硅氧烷微球。采用扫描电镜(SEM)、动态光散射(DLS)和红外光谱(FT-IR)等分析手段分别对功能性微球的微观形貌、粒径分布和微观结构进行表征。将这种表面功能性的单分散聚硅氧烷微球按照0.4%的添加量加入光学级聚碳酸酯(PC)树脂中,可制备出透光率75.6%、雾度94.6%性能优良的光散射材料。     

疏水高分子介导可动芯SiO2杂化纳米粒子的仿生合成

在疏水高分子胶体模板——含氟丙烯酸酯(FA)共聚物乳胶粒中引入能够介导SiO2原位沉积的聚胺催化活性点-甲基丙烯酰氧乙基三甲基氯化铵(DMC),以四甲氧基硅烷(TMOS)为硅源,在环境条件下可控合成了核壳型FA共聚物/SiO2杂化纳米粒子.高温煅烧除去聚合物核质,可得到中空的SiO2纳米粒子,结合FTIR、EDX、TGA以及XPS等表征数据印证了SiO2的沉积主要发生在聚合物模板的表面.进一步考察了反应条件,如聚胺功能单体DMC的浓度、TMOS的浓度以及反应时间对SiO2杂化纳米粒子的形貌与组成的影响.实验结果表明增加DMC或者TMOS的浓度,适当延长反应时间,均可增加SiO2粒子的沉积速率,导致SiO2壳层的厚度增加,并且杂化粒子的形貌由凹陷多褶皱的核壳结构向可动芯结构转变.由于FA共聚物模板的强疏水性,增加有机核层和无机壳层间的不相容排斥,最终导致核壳层间空腔的形成,得到含可动芯的核壳型SiO2杂化粒子.     

Template Polymerization-solvent Extraction：A New Method for Fabrication of Hollow Polysiloxane Particles

Hollow polysiloxane particles with diameters between 1.40 and 1.60 micrometres were fabricated by consecutive cocondensation of methyltrimethoxysilane and diphenyldimethoxysilane monomers onto polydiphenylsiloxane,subsequently removing the templated polydiphenylsiloxane by exposure to solvents.TEM and AFM measurement reveal that there are obvious hollow sphere structures for the polysiloxane microsphere particles.The hollow spheres are envisioned to have applications in areas ranging from dye-industry,catalysis,pharmaceutics to materials science.     

Novel hollow microcapsules based on iron-heparin complex multilayers

Iron-polysaccharide complex have been extensively utilized in the treatment of iron deficiency anemia for parenteral administration. Herein, a novel iron-heparin complexed hollow capsules with nanoscaled wall thickness have been fabricated by means of alternating deposition of ferric ions (III) (Fe+) and heparin (Hep) onto the surface of submicroscaled (488 nm) and microscaled (10.55 microm) polystyrene latex particles via both electrostatic interaction and chemical complexation processes, followed by dissolution of the cores using tetrahydrofuran. Confocal micrographs and atomic force microscopy (AFM) images prove that iron-heparin complexed submicroscaled hollow capsules keep spherical shapes in solution and even after drying. The activated partial thromboplastin time (APTT) assay shows that complexing with ferric ions do not compromise the catalytic capacity of heparin to promote antithrombin III-mediated thrombin inactivation. The anticoagulant activity value of (Fe3+/Hep)8 capsules is evaluated to be about 95.7 U/mg, indicating that approximately 0.55 mg heparin was in 1 mg powder of submicroscaled (Fe3+/Hep)8 hollow capsules. Compared with the same dosage of heparin, iron-heparin complexed hollow capsules display a more prolonged anticoagulant duration than heparin. All these results reveal that such submicroscaled iron-heparin complexed hollow capsules have application potential as an injectable anticoagulant vehicle.     

Interface-directed self-assembly of gold nanoparticles and fabrication of hybrid hollow capsules by interfacial cross-linking polymerization

Amphiphilic gold nanoparticles (AuNPs) were produced at liquid-liquid interface via ligand exchange between hydrophilic AuNPs and disulfide-containing polymer chains. By using oil droplets as templates, hybrid hollow capsules with AuNPs on the surfaces were obtained after interfacial cross-linking polymerization. The volume ratio of toluene to water exerts an important effect on the size of capsules. The average size of the capsules increases with the volume ratio. Transmission electron microscopy (TEM), scanning electron microscopy (SEM), and atomic force microscopy (AFM) were used to characterize the hollow structures. In this research, not only one-component but also multicomponent hollow capsules were prepared by copolymerization of acrylamide and hybrid AuNPs at liquid-liquid interface. Because of the improvement in hydrophilicity of the hollow capsules, the average size of multicomponent capsules is bigger than one-component ones in aqueous solution.     

Highly stable and biocompatible nafion-based capsules with controlled permeability for low-molecular-weight species

Biocompatible hollow capsules have been formed by electrostatic layer-by-layer self-assembly of a perfluorinated ionomer (Nafion) in alternation with ferric ions onto polystyrene latex particles or organic microcrystals, followed by dissolution of the cores by tetrahydrofuran or dimethylformamide. The stepwise growth of multilayers was followed by UV-visible spectroscopy and microelectrophoresis. The formation of hollow capsules was verified by confocal laser scanning microscopy and scanning force microscopy. The hollow Fe3+/Nafion capsules displayed high stability over a wide range of pH values and at high temperature. Fluorescein transport through the Fe3+/Nafion capsule wall was studied by means of photochemical bleaching and recovery (PBR) of the capsule interior. A diffusion model is suggested to calculate the diffusion coefficient for low-molecular-weight species, which was determined to be in the order of 10(-12) cm2s. The permeability can be manipulated by changing the wall thickness of the capsules.     

Nanoengineered polymeric S-layers based capsules with targeting activity

Nanostructured polymeric capsules are regarded as highly promising systems with different potential applications ranging from drug delivery, biosensing and artificial cells. To fully exploit this potential, it is required to produce bio-activated stable and biocompatible capsules. To this purpose, in present work we proposed the combination of the layer-by-layer self assembly method with bacterial S-layer technology to fabricate stable and biocompatible polymeric capsules having a well defined arrangement of functional groups allowing the covalent attachment of antibody molecules. Hollow microcapsules were obtained by the layer-by-layer self assembly of oppositely charged polyelectrolytes onto colloidal particles, followed by removal of the cores at acidic pH. S-layers were crystallized onto the shell of the obtained capsules. Quartz crystal microbalance was used to characterize the crystallization process onto planar surfaces. S-layer containing capsules were investigated by atomic force microscopy. Immunoenzymatic tests were performed to assess the effective modification of the S-layer with antibody molecules both on planar surfaces and on hollow capsules. Fluorescent microscopy was employed to visualize the presence of the antibody molecules onto the capsule shell and immunological tests used to assess the bioactivity of the immobilized antibodies. Finally, the in vitro cytotoxicity of fabricated S-layer containing capsules was studied. The obtained results demonstrated the possibility to fabricate bio-activated S-layer containing capsules with improved features in terms of biocompatibility.     

LIGHT-SCATTERING STUDY OF POLYELECTROLYTE HOLLOW CAPSULES

Silver halide (AgX) microcrystal was used as template to synthesize hollow polyelectrolyte capsules. These hollow capsules were characterized by laser light scattering (LLS) used to measure the size of the capsules in solution. The ratio of hydrodynamic radius (Rh) from dynamic LLS to the radius of gyration (Rg) from static LLS is almost unity, revealing that the entities are hollow in solution. The results suggest that the LLS method can be regarded as a good complement to the confocal laser scanning microscopy (CLSM) method for the characterization of small hollow capsules, and it possesses the advantage of not needing fluorescence labeling.     

Template Polymerization Based on Stober Method： an improved Method for Fabrication of Hollow Polysiloxane Spheres

Composite materials derived from coating or templating colloidal particles often exhibit unique properties and therefore has been intensively pursued1-3. For example, hollow spheres produced by colloidal templating are of interest in diverse applications,…     

Silicone nanocapsules templated inside the membranes of catanionic vesicles

A simple and effective way to synthesize hollow silicone resin particles of controlled diameter is presented. The synthesis utilizes catanionic vesicles as templates for the polycondensation/polymerization processes of 1,3,5,7-tetramethylcyclotetrasiloxane (D4H) within their membranes. Two different surfactant systems were used to form the vesicular templates: mixtures of dodecyltrimethylammonium bromide (DTAB) and sodium dodecylbenzenesulfonate (SDBS) in the cationic (the DTAB/SDBS system) or anionic (the SDBS/DTAB system) rich region of the phase diagram. The templates obtained from these surfactant mixtures form spontaneously unilamellar vesicles in aqueous solution. The vesicular templates swell upon addition of D4H, thus increasing their size. The silicone resin was obtained in acid- or base-catalyzed polycondensation and ring-opening polymerization processes of D4H. In the case of the DTAB/SDBS system the formation of a densely cross-linked silicone material with SiO3/2 units allowed the nanocapsules to retain the vesicular shape after removal of the template, whereas in the SDBS/DTAB system, the polymer produces capsules which are too smooth to support surfactant lysis. The morphology of the silicone nanocapsules was analyzed using transmission electron microscopy (TEM) and, in some cases, atomic force microscopy (AFM). TEM and AFM reveal discrete hollow particles with a small amount of linked or aggregated hollow silica shells.     

Self-assembly, optical behavior, and permeability of a novel capsule based on an azo dye and polyelectrolytes

A novel capsule composed of an azo dye, Congo red (CR), and different polymers, including poly(styrenesulfonate, sodium salt) (PSS), poly(allylamine hydrochloride) (PAH), and poly(diallyldimethylammonium chloride) (PDDA), have been successfully fabricated by the layer-by-layer self-assembly technique. The stepwise linear deposition process was monitored by means of UV-visible absorption measurements. The formation of hollow capsules was verified by confocal laser scanning microscopy (CLSM) and scanning force microscopy (SFM). The resulting hollow PSS/PAH/CR/PDDA capsules displayed a sensitive response to visible light. Optical changes of the hollow capsules prior to and after the photoreaction were investigated in detail by means of UV-visible spectroscopy, CLSM, and SFM. It was found that the photochemical reaction of the assembled hollow capsules depends strongly on the matrix. Qualitative results on the permeability of the hollow capsule walls with CR as one component indicate that the permeability of the walls can be easily photo-controlled at varying irradiation time intervals without addition of external chemicals.