介孔中空二氧化硅微球制备及吸附缓释性能研究

以用分散聚合法制得的不同粒径单分散阳离子型聚苯乙烯球为模板、十二胺为表面活性剂,通过溶胶-凝胶方法,在模板上包裹二氧化硅壳,并通过浸渍和焙烧制备了具有介孔结构的中空二氧化硅微球.TEM,SEM显示微球具有很好的单分散性和中空结构.小角XRD表明球壳上具有六方介孔结构.实验表明控制模板粒子大小可改变介孔中空二氧化硅微球粒径,改变正硅酸乙酯浓度可以调整二氧化硅球壳厚度.通过对丁基罗丹明B染料的吸附装载与释放实验证实了其有很好的渗透性和缓释性能.     

缓蚀剂负载中空SiO2微球的制备及性能EI北大核心CSCD

以乳液聚合法制备的聚苯乙烯微球为模板制备中空介孔二氧化硅微球,经扫描电子显微镜、透射电子显微镜、热重分析、小角度X射线衍射、氮气吸附–脱附等手段对制备得到的中空微球进行性能结构表征。考察了氨水和硅源前驱体用量等制备条件对中空微球的尺寸、介孔孔径、球壳厚度等的影响,6.25 mL氨水和10 g正硅酸乙酯的用量为最佳制备条件。中空SiO2微球作为载体,负载缓蚀剂苯并三氮唑,并对负载缓蚀剂的微球表面进行高分子双电层的修饰,释放曲线实验表明,高分子双电层修饰使微球中缓蚀剂释放速率降低5倍。     

缓蚀剂负载中空SiO_2微球的制备及性能

以乳液聚合法制备的聚苯乙烯微球为模板制备中空介孔二氧化硅微球,经扫描电子显微镜、透射电子显微镜、热重分析、小角度X射线衍射、氮气吸附–脱附等手段对制备得到的中空微球进行性能结构表征。考察了氨水和硅源前驱体用量等制备条件对中空微球的尺寸、介孔孔径、球壳厚度等的影响,6.25 mL氨水和10 g正硅酸乙酯的用量为最佳制备条件。中空SiO_2微球作为载体,负载缓蚀剂苯并三氮唑,并对负载缓蚀剂的微球表面进行高分子双电层的修饰,释放曲线实验表明,高分子双电层修饰使微球中缓蚀剂释放速率降低5倍。     

纳米介孔二氧化硅的制备和修饰研究

以十六烷基三甲基溴化铵(CATB)为模板剂、正硅酸乙酯(TEOS)为硅源,采用化学沉淀法制备纳米介孔二氧化硅;通过氨基硅烷偶联剂和巯基硅烷偶联剂(1∶1)的共同作用,在无水体系中制备氨基和巯基共同修饰的纳米介孔二氧化硅,并通过扫描电镜、X-射线衍射仪和傅立叶变换红外光谱仪对修饰前后的纳米介孔二氧化硅进行表征。结果表明,纳米介孔二氧化硅粒子形态均一,平均粒径在100nm左右,分散性良好;修饰后的纳米介孔二氧化硅粒子形貌及分散性依然良好,平均粒径在150nm左右。该研究为纳米介孔二氧化硅载药体系的研究提供了新思路和实验基础。     

两步法和双模板法制备中空二氧化硅微球的比较

研究两步法制备中空二氧化硅微球,对比分析了两步法和双模板法(本课题组已有成果)在产物形貌、性能上的异同。结果表明,两种方法制备的中空二氧化硅微球在形貌上都具有规则球形和中空介孔结构,两步法产物具有更大的比表面积、更完美的球形和更宽的孔径分布,所得硅球官能团单一,模板去除更为彻底,微球纯度更高,制备周期短,过程简单,更为经济,而双模板法产物孔径分布窄,具有更好的介孔结构。     

介孔二氧化硅花球的制备及药物缓释性能研究

采用溶胶-凝胶法,以正硅酸乙酯为硅源、十六烷基三甲基溴化铵(CTAB)为模板,在碱性条件下合成了尺寸均匀、形状规则的花状形貌的介孔状二氧化硅微球。基于二氧化硅花球特殊的表面褶皱和内部的介孔孔道,将其作为载体负载模型药物布洛芬,探究其药物缓释性能。结果表明,所制备的介孔二氧化硅花球对布洛芬模型药物的负载量为701.63 mg·g~(-1),明显高于传统药物载体材料。此外,对介孔二氧化硅/布洛芬复合粒子进行缓释实验研究,发现10 h后布洛芬的释放量为74.60%,表明其具有较好的药物缓释性能。     

制备条件对介孔分子筛MCM-41形貌的影响研究

本文以正硅酸乙酯(TEOS)为硅源,十六烷基三甲基溴化铵(CTAB)为介孔模板剂制备MCM-41介孔分子筛,通过改变制备体系条件来调控MCM-41的形貌,考察了制备体系水用量、制备体系氨水用量、TEOS滴加速率对所得MCM-41产物形貌的影响。结果表明:制备体系水用量和氨水用量增大会使所得产物由棒状向球形颗粒转变,TEOS滴加速率加快有利于形成尺寸均匀的棒状MCM-41。最后对MCM-41形貌演变过程进行了分析。     

高吸附性能介孔磁性复合碳球的制备

以正硅酸乙酯(TEOS)为硅前驱体,间苯二酚-甲醛树脂(RF)为碳源,在表面活性剂十六烷基三甲基溴化铵(CTAB)的辅助作用下,采用原位聚合法制备了介孔磁性复合碳球Fe3O4@C-M。考察了醇水比〔V(乙醇)∶V(水)〕、表面活性剂用量、TEOS用量和水热温度(HT)对碳球的形貌、粒径和表面孔结构的影响。在84 mL乙醇/水混合液〔V(乙醇)∶V(水)=3∶4〕、CTAB 0.6 g、TEOS 4 mL、水热温度100℃下制备得到Fe3O4@C-M,采用TEM、XRD、XPS、BET、TGA、VSM对其进行表征。结果表明,Fe3O4@C-M的比表面积为553m2/g,较不引入硅前驱体时制备的磁性复合碳球Fe3O4@C-0增大1.7倍,介孔孔容占比由18%增大到83%。考察Fe3O4@C-M对红霉素的吸附性能,饱和吸附量为255 mg/g;用乙酸正丁酯对吸附后材料进行再生,5次循环再生后吸附量维持在初始吸附量的85%以上。     

介孔二氧化硅-阿维菌素缓释体系的制备与性能研究

以正硅酸乙酯(TEOS)为硅源,氨水为碱性催化剂,采用无模板法制备介孔二氧化硅和中空介孔二氧化硅,选用持效期较短的阿维菌素作为模型药物构成缓释体系,通过扫描电镜(SEM)、透射电镜(TEM)、比表面仪(BET)、傅里叶红外光谱仪(FTIR)和紫外分光光度计(UV)对二氧化硅材料的形貌、粒径、载药量进行表征和测定,同时测试其缓释性能。探讨了溶剂蒸发法和超声浸渍法两种不同载药方法对缓释性能的影响。结果表明,两种农药缓释载体均呈球形,平均粒径500 nm,其中中空介孔二氧化硅载体具有独特的中空介孔复合结构,超声浸渍法载药效果较好,两种载体的载药量分别为48. 89%和52. 58%,中空介孔二氧化硅-阿维菌素缓释体系的缓释区间较大,缓释效果较好,31 h才基本达到平衡。     

CTAB含量对介孔空心微球结构的影响

介孔空心微球具有大的空心腔体和壳体上小的介孔结构,使得介孔空心微球结构材料作为一种新型功能材料有着广阔的应用前景。本文使用喷雾干燥法合成介孔空心微球,以CTAB作为致孔剂,TEOS作为硅源,系统研究了不同CTAB含量下产物的结构,发现n（CTAB）/n（TEOS）=0.2时,产物颗粒具有较好的空心结构,颗粒外壳上的介孔有序度高,当n（CTAB）/n（TEOS）的值增加时,产物中的空心颗粒含量减小,而且壳上的介孔的有序度下降,介孔孔壁厚度也减小。     

柔软的球状和长方体状氧化硅中空结构的制备研究

采用自组装形成的芘纳米结构作为模板,成功地制备了柔软的球状和长方体状氧化硅中空结构.当不同量的芘在十六烷基三甲基溴化铵(CTAB)溶液中自组装时,产生的自组装结构展现出明显的从球状到长方体状的形貌变化.这些结构被用作氧化硅前驱体溶胶-凝胶反应的模板,获得了球状和长方体状氧化硅/芘复合结构.通过乙醇除去模板后,生成了柔软的球状(直径约为400nm)和长方体状(长为0.5—2.5μm)的氧化硅中空结构.这些结果展现了采用有机纳米结构作为模板来合成无机中空结构的优势:合成简便、结构多样以及结构形貌的灵活可控.     

Vesicle-templating poly (3,4-ethylenedioxythiophene) hollow microspheres with enhanced electrocatalytic activity toward ascorbic acid oxidation

Poly(3,4-ethylenedioxythiophene) (PEDOT) hollow microspheres ranging from 50 to 950?nm are synthesized by chemically oxidative polymerization of 3,4-ethylenedioxythiophene using ammonium persulfate in the aqueous solution of cetyltrimethylammonium bromide (CTAB) and sodium dodecylbenzenesulfate (SDBS). Vesicles formed by CTAB and SDBS serve as templates for the formation of PEDOT hollow microspheres. The obtained PEDOT hollow microspheres were characterized by Fourier transform infrared spectroscopy, elemental analysis, X-ray photoelectron spectroscopy, and conductivity measurement. Compared to PEDOT granular particles, PEDOT hollow microspheres showed a more effective electrocatalytic activity in lowering the ascorbic acid oxidation potential.     

Cooperative self-assembly of silica-based mesostructures templated by cationic fluorocarbon/hydrocarbon mixed-surfactants

In this work, we have systematically studied the influences of reaction temperature, silica sources, and nature of surfactant templates on cooperatively self-assembled mesostructures. Both positively charged hydrocarbon (HC) surfactant cetyltrimethylammonium bromide (CTAB) and fluorocarbon (FC) surfactant FC-4 were used as the templates, and four silica sources tetramethyl orthosilicate (TMOS), tetraethyl orthosilicate (TEOS), 1,2-bis (trimethoxysilyl) ethane (BTME) and 1,2-bis (triethoxysilyl) ethane (BTEE) were used as the precursors. When CTAB and FC-4 were applied as mixed templates and BTME or BTEE as the silica source, it was found that ordered mesostructure with a hollow morphology can be successfully obtained only at temperatures higher than the demixing temperature (T_d) of two surfactants. When FC-4 was used as a single template, generally vesicular structures were obtained regardless of the silica sources. In the case of CTAB/FC-4 co-templates, the utilization of pure silica sources (TEOS and TMOS) gave rise to nano-particles with neither hollow morphology nor the ordered mesostructure. The above results can be understood by the interactions between the templates and the silica sources considering the hydrophobic sequences of surfactants (CTAB < FC-4) and different silica precursors (TMOS < TEOS < BTME < BTEE). It is anticipated that by carefully tuning the interaction between surfactant templates and silica species, novel mesoporous materials with controlled composition, structure and morphology can be designed and fabricated.     

磷酸化二氧化硅填充磺化聚醚醚酮质子交换膜的制备及表征

制备了两种磷酸化改性的介孔二氧化硅亚微米球形颗粒,分别为仅外表面接枝磷酸根基团的颗粒(PMPS-Ⅰ)和内外表面均接枝磷酸根基团的颗粒(PMPS-Ⅱ)。颗粒具有均一的尺寸和规则排布的六面体一维贯通孔道。将制备的二氧化硅颗粒与磺化聚醚醚酮(SPEEK)溶液共混制备杂化膜。与填充PMPS-Ⅰ的杂化膜相比,填充PMPS-Ⅱ的杂化膜显示出较好的质子传导性能。当PMPS-Ⅱ的填充量为5%(质量)时,杂化膜在60℃、100%相对湿度下最高质子传导率为0.241 S·cm^-1。研究结果表明,连续贯通的质子传递通道有助于提高杂化膜的质子传导率。     

单分散Fe3O4亚微米球的粒径控制合成及表征

采用溶剂热还原法,以FeCl3.6H2O和乙二醇为原料,在200℃相对低温条件下成功合成四氧化三铁微米球。通过改变实验条件,可在115～435nm有效调控Fe3O4亚微米球的粒径。采用X射线衍射仪(XRD)、透射电子显微镜(TEM)和扫描电子显微镜(SEM)对样品的结构、粒径、形貌和组成进行了分析,并于室温测试了它的磁学性能。结果表明,产物Fe3O4亚微米球为反尖晶石结构,330nmFe3O4亚微米球的矫顽力(Hc)为6644.93A/m,饱和磁化强度(Ms)为81.2emu/g,剩余磁化强度(Mr)为14.6emu/g。研究了乙二醇和NaOH的浓度、反应时间对产物形貌的影响,结果表明,乙二醇在Fe3O4亚微米球的形成过程中起着关键作用,并提出了可能的生长机理。     

Polycarbazole by chemical oxidative interfacial polymerization: morphology and electrical conductivity based on synthesis conditions

Polycarbazole (PCB) was synthesized via an interfacial polymerization method using carbazole monomer and ammonium persulfate as the oxidizing agent. The effects of surfactant type (non‐ionic Tween 20, cationic cetyltrimethylammonium bromide (CTAB) and anionic sodium dodecylsulfate) and concentration on the synthesized PCB were investigated based on the roles of micelle formation. Electron microscopy images revealed various PCB morphologies depending on the surfactant type and concentration. The newly found morphological structures of the PCB were macroporous honeycomb, connected hollow sphere and smaller hollow sphere depending on the surfactant type. The highest electrical conductivity of doped PCB_CTAB obtained was 11.3 ± 0.36 S cm^?1. The electrical conductivity values of the doped PCB synthesized with CTAB were higher than that without a surfactant by three orders of magnitude. © 2016 Society of Chemical Industry     

Facile Fabrication of Ultrafine Hollow Silica and Magnetic Hollow Silica Nanoparticles by a Dual-Templating Approach

The development of synthetic process for hollow silica materials is an issue of considerable topical interest. While a number of chemical routes are available and are extensively used, the diameter of hollow silica often large than 50 nm. Here, we report on a facial route to synthesis ultrafine hollow silica nanoparticles (the diameter of ca. 24 nm) with high surface area by using cetyltrimethylammmonium bromide (CTAB) and sodium bis(2-ethylhexyl) sulfosuccinate (AOT) as co-templates and subsequent annealing treatment. When the hollow magnetite nanoparticles were introduced into the reaction, the ultrafine magnetic hollow silica nanoparticles with the diameter of ca. 32 nm were obtained correspondingly. Transmission electron microscopy studies confirm that the nanoparticles are composed of amorphous silica and that the majority of them are hollow.     

Relationship between electrical and mechanical loss tangents of hollow glass powder reinforced epoxy composites: A pilot study

This study was focused on the synthesis of monodisperse poly(n‐butyl methacrylate‐co‐methyl methacrylate) submicrospheres via soap‐free emulsion polymerization and on their characterization. The glass‐transition temperatures of poly(n‐butyl methacrylate) and poly(methyl methacrylate) were approximately 25 and 110°C, respectively. Therefore, submicrospheres with different glass‐transition temperatures could be obtained through the variation of the copolymer composition. In addition, relationships between the monomer feed concentration (M₀) and the Mark–Houwink constant (α) for the copolymer submicrospheres were proposed. The molecular weights of the copolymer submicrospheres decreased sharply with an increase in the weight fraction of n‐butyl methacrylate. On the contrary, the particle diameter increased linearly from 277 to 335 nm with an increase in the weight fraction of n‐butyl methacrylate. The α values decreased with an increase in M₀, and this indicated that the branched structures of the copolymer submicrospheres were easily obtained when M₀ was higher than 0.11 g/mL of water. Consequently, the results of this study are expected to provide useful information for the synthesis of monodisperse copolymer submicrospheres by soap‐free emulsion polymerization. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Preparation of hollow mesoporous silica spheres by a sol–gel/emulsion approach

Hollow mesoporous silica spheres were synthesized by a sol–gel/emulsion (oil-in-water/ethanol) approach, in which cetyltrimethylammonium bromide (CTAB) surfactant was employed to stabilize and direct the hydrolysis of oil droplets of tetraethoxysilane (TEOS). The diameters of the hollow spheres can be tuned in the range from 210 to 720 nm by varying the ratio of ethanol-to-water and their shell thickness can be mediated by changing the concentration of CTAB used in the system. BET surface areas of the hollow silica spheres are determined to be in the range of 924–1766 m² g^?1 and their pore sizes are around 3.10 nm as determined by BJH method.