微球材料尺寸和结构控制的过程工程

微球材料的粒径均一性和结构可控性直接影响其应用效果,这对过程工程提出了挑战。在发展微孔膜乳化过程制备均一乳液和微球的基础上,对均一乳液的形成机理进行了研究,通过对液滴形成过程的控制,在油/水、水/油、水/油/水等体系成功制备出了均一微球。通过发展微球结构演变过程的定量研究方法,成功对微球结构进行了调控;针对生化工程对超大孔微球的重要需求,发展了超大孔微球制备方法,实现了孔径在100 nm到微米级的调控。研究了粒径均一性和结构对其应用效果的影响。微球应用于生物分离介质时,粒径均一性提高了蛋白质的分离度;超大孔微球可使超大生物分子快速进入介质内部,显著提高纯化回收率。微球应用于胰岛素口服药物载体时,粒径对其在消化道的分布有显著影响,中空-多孔微球显示了最佳的降血糖效果。     

微球材料尺寸和结构控制的过程工程

微球材料的粒径均一性和结构可控性直接影响其应用效果,这对过程工程提出了挑战。在发展微孔膜乳化过程制备均一乳液和微球的基础上,对均一乳液的形成机理进行了研究,通过对液滴形成过程的控制,在油/水、水/油、水/油/水等体系成功制备出了均一微球。通过发展微球结构演变过程的定量研究方法,成功对微球结构进行了调控;针对生化工程对超大孔微球的重要需求,发展了超大孔微球制备方法,实现了孔径在100 nm到微米级的调控。研究了粒径均一性和结构对其应用效果的影响。微球应用于生物分离介质时,粒径均一性提高了蛋白质的分离度;超大孔微球可使超大生物分子快速进入介质内部,显著提高纯化回收率。微球应用于胰岛素口服药物载体时,粒径对其在消化道的分布有显著影响,中空-多孔微球显示了最佳的降血糖效果。     

复乳液滴模板法结合溶剂去除法制备P(MMA-MAA)超大孔聚合物微球

以聚(甲基丙烯酸甲酯-甲基丙烯酸)[P(MMA-MAA)]为主要微球材质,两亲性聚(乳酸-聚乙二醇)二嵌段共聚物(PELA)为辅助材质,通过复乳液滴模板法结合溶剂去除法,制备了微米尺度贯穿孔道结构的超大孔P(MMA- MAA)微球,考察了油相中材质浓度、内水相盐浓度、复乳演变时间等对微球形态及孔道结构的影响,分析了微球表面孔隙的演变机理. 在P(MMA-MAA)浓度100 g/L和PELA浓度30~40 g/L、外水相PVA浓度25 g/L、内水相NaCl浓度1~5 g/L、乳液熟化时间0~30 min的条件下,可制备出形态较好的超大孔微球,微球的表面孔径可达数微米,孔隙率最高可达95%. 超大孔微球形成后,对其骨架进行共价交联,可形成刚性微球骨架.     

用于单克隆抗体纯化的仿生多肽超大孔PGMA微球制备及其性能

以仿生多肽配基FYEILHC为亲和配基、以葡聚糖修饰的聚甲基丙烯酸缩水甘油酯[Dextran-poly(glycidyl methacrylate), Dextran-PGMA]超大孔微球为基质，制备用于单克隆抗体纯化的仿生多肽超大孔PGMA微球，在环氧氯丙烷中滴加2 mol/LNaOH使其表面衍生出环氧基，在表面修饰FYEILHC；用扫描电镜表征微球表面形貌，用AKTA蛋白纯化系统考察了Dextran-PGMA微球和琼脂糖微球对抗体的动态吸附量随线性流速的变化。结果表明，偶联FYEILHC后Dextran-PGMA微球仍能保持其大孔结构，在923 cm/h线性流速下，其对抗体的动态吸附量仅下降约8%，而琼脂糖微球的动态吸附量则迅速下降25%。表明在较高流速下，抗体在Dextran-PGMA微球上的传质性能较好。吸附?用0.1 mol/L NaOH原位清洗重复40次后，Dextran-PGMA微球对抗体的动态吸附量约为(21?1) mg/mL，表明微球具有良好的化学稳定性；血清中回收的抗体纯度为95.0%，表明仿生多肽亲和介质具有从复杂生物样品中纯化抗体的巨大潜力，可满足高流速、高通量抗体分离纯化需求。     

超大孔聚(苯乙烯-甲基丙烯酸缩水甘油酯)共聚微球的制备及孔结构的调控

使用表面活性剂反胶团法制备超大孔聚(苯乙烯-甲基丙烯酸缩水甘油酯)[P(ST-GMA)]共聚微球,考察了功能单体GMA含量、油溶性表面活性剂、稀释剂、交联剂对微球孔径的影响. 结果表明,随GMA含量增加,微球孔径显著增大;表面活性剂用量从1.6 g增加到2.0 g时,微球孔径由100 nm增加到720 nm;随稀释剂疏水性增强,微球孔径增大;交联剂用量由1.0 g增加到2.0 g,微球孔径由550 nm变为100 nm左右. 在此基础上,通过条件优化合成了具有特定孔径的不同功能单体GMA含量的超大孔P(ST-GMA)共聚微球,可连接不同配基,用于色谱分离介质及酶的固定化.     

复乳法制备大孔聚合物微球

研究在不使用乳化剂和致孔剂的条件下采用两亲性聚合物单甲氧基聚乙二醇聚乳酸共聚物制备大孔微球,确定了形成大孔结构的必要条件及孔径的控制方法,并对大孔微球的形成机理进行了探讨. 结果表明,两亲性聚合物单甲氧基聚乙二醇聚乳酸共聚物能较好地稳定乳液进而形成贯穿孔结构,而选用疏水性聚合物聚乳酸和聚(乳酸-羟基乙酸)时只能制备出单腔室结构的微球;当内水相与油相体积比在1:4~1:2、油相溶剂去除分两步时,能形成孔径在100 nm以上的大孔聚合物微球,大孔微球的孔径随着初乳化速率的增大而减小.     

复乳法制备大孔琼脂糖分离介质与疫苗结合性能研究

大孔分离介质在分离纯化特别是超大生物分子分离纯化领域具有十分重要的应用意义。受材料性质和制备技术所限制,大孔分离介质以聚合物材料最为常见,针对琼脂糖的大孔分离介质较为少见。通过复乳法制备大孔琼脂糖微球,研究制备条件对微球形貌与成孔情况以及粒径与分布等的影响,发现该微球具备微米级超大孔结构,且制备条件对孔道结构的影响呈现一定规律,琼脂糖溶液浓度、内/外油相与水相比例、初乳转速和成球转速等都对成孔性至关重要。激光共聚焦显微镜实验结果表明,衍生后的大孔琼脂糖分离介质对乙肝表面抗原具有良好的结合能力,使其能够完全进入微球内部。与传统琼脂糖介质相比,大孔琼脂糖介质能够更快速、充分结合大分子疫苗,在超大分子分离纯化领域应用前景广阔。     

交联壳聚糖磁性微球制备及吸附性能研究

采用超声波辅助化学共沉淀法制备纳米Fe3O4,在此基础上选用乳化交联法,以戊二醛为交联剂,壳聚糖为单体包埋磁性纳米颗粒,合成了微米及纳米尺度上具有高吸附性、介质分离的磁性壳聚糖纳米微球(MCTS),并对复合材料的吸附性能进行了讨论。通过将壳聚糖包裹纳米磁性粒子制备成的磁性壳聚糖微球,具有比表面积大、多孔、易回收、可再生等优点,并且该磁性微球稳定性好、吸附性能强,有效地提高了壳聚糖的应用价值,而对于金属废水处理、药物的分离纯化和天然药物有效成分的富集纯化等意义重大。     

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。     

生物模板法制备磁性中空微球的方法和应用

磁性中空微球在功能性吸附、酶固定化载体、物质的分离纯化、活性物质和药物的封装与控释、靶向给药、污染防治、食品和材料学等领域有突出的应用价值。文章综述了利用生物模板法制备磁性中空微球的制备原理和最新研究成果,并主要分析了软模板法和自模板法两种制备工艺。软模板法工艺主要通过吸附-高温炭化法除去生物模板材料获得固定外形的磁性中空微球。自模板法制备磁性中空微球可依据生物材料自身成分经水热碳化反应或在惰性气体氛围保护下的高温炭化反应生成具有特殊官能团结构的中空碳微球,并将磁性物质溶入或吸附到中空微球中,具体分为水热碳化法和浸渍-高温炭化法;也可将制备好的磁性物质吸附于经过特殊处理过的生物模板材料表面,如吸附-共沉淀法和高温炭化-共沉淀法。总之,生物模板法制备磁性中空微球条件较为温和、无污染,生物模板材料对人体无毒,特别适合于食品、医药等行业的应用,具有很好的生产应用前景。     

光敏性多元核-壳微球絮凝剂的制备

以Stöber法制备的单分散SiO2为核,采用溶胶-凝胶、界面沉积和表面活性剂模板法制备了多元核-壳结构微球SiO2@TiO2-Ag@SiO2,利用FT-IR、SEM、XRD、UV-Vis DRS、N2吸附-脱附、XPS对其结构和形貌进行了表征。结果显示：微球平均孔径、比表面积分别为2 nm、72.73 m2/g;受最外层SiO2影响,XRD未观察到锐钛矿相TiO2的特征衍射峰;紫外-可见漫反射光谱证实SiO2@TiO2-Ag@SiO2在365 nm处有吸收。在模拟太阳光照射下100 min,SiO2@TiO2-Ag@SiO2微球对亚甲基蓝(MB) 的光催化脱色率为97.6％;自然光下,对甲基橙溶液(MO)的絮凝沉淀时间为40 min,脱色率达99.7％。     

Chemical coating polysaccharide on gigaporous polystyrene microspheres as a high‐speed protein chromatography matrix

Permanent polysaccharide coating on gigaporous polystyrene (PS) microspheres was achieved through direct chemical grafting of dextran via a facile method, minimizing nonspecific adsorption of proteins and providing easily derivatizable groups on microspheres. Chloroacetylated PS microspheres (PS‐Cl) were first developed through acetylation, and hydrophilic dextran was directly grafted to hydrophobic PS‐Cl via a Williamson reaction (PS‐Dex). The homogeneous side‐bound dextran coating has the advantage of masking the hydrophobic surface of the PS microspheres, while maintains their original gigaporous structure. After grafting, the hydrophobic surface of the PS microspheres was effectively masked, and nonspecific protein adsorption was greatly reduced. Moreover, the hydroxyl‐rich coating can be easily derivatized through classical chemical methods. A column packed with PS‐Dex presented both good permeability and mechanical strength at high flow velocities of up to 3612 cm/h. These results implied that PS‐Dex should be an ideal matrix for high‐speed protein chromatography. POLYM. ENG. SCI., 56:1407–1414, 2016. © 2016 Society of Plastics Engineers     

回流法制备TiO2微球及其结构和催化性能研究

采用回流法制备了介孔TiO2微球催化剂,利用XRD、FE -SEM、BET等方法对所制备的催化剂进行了表征,并与溶剂热法制备的样品进行比较,研究不同制备方法对TiO2结构、彤貌及催化性能的影响.结果表明,回流法制备的样品为锐钛矿单相微球,晶粒间堆积形成介孔结构,比表面积大;而溶剂热法制备的介孔样品含金红石和锐钛矿两相.以EtOH/HCl为回流溶剂制备的样品孔径约为5nm,孔径分布窄,比表面积可达496 m2/g,光催化去除Cr(Ⅵ)反应速率快,去除率达到99％.     

回流法制备TiO_2微球及其结构和催化性能研究

采用回流法制备了介孔TiO2微球催化剂,利用XRD、FE-SEM、BET等方法对所制备的催化剂进行了表征,并与溶剂热法制备的样品进行比较,研究不同制备方法对TiO2结构、形貌及催化性能的影响。结果表明,回流法制备的样品为锐钛矿单相微球,晶粒间堆积形成介孔结构,比表面积大;而溶剂热法制备的介孔样品含金红石和锐钛矿两相。以EtOH/HCl为回流溶剂制备的样品孔径约为5 nm,孔径分布窄,比表面积可达496 m2/g,光催化去除Cr（Ⅵ）反应速率快,去除率达到99%。     

Mesoporous TiO<Subscript>2</Subscript> microspheres synthesized via a facile hydrothermal method for dye sensitized solar cell applications

Mesoporous TiO₂ microspheres were successfully synthesized by a facile hydrothermal process and the obtained product was sintered at 450 °C. The sintered TiO₂ powder was characterised by powder X-ray diffraction pattern and the result shows pure anatase phase with good crystalline nature. The morphological image of field emission scanning electron microscopy and high resolution transmission electron microscopy shows spherical shape and size of the particles is around 100 to 300 nm. The Brunauer–Emmett–Teller surface area of synthesized TiO₂ material was 56.32 m² g^?1 and average pore width of synthesized materials was 7.1 and 9.3 nm. Bimodal pore structure of TiO₂ microspheres has been very effective for electrolyte diffusion into photoanode in dye sensitized solar cells. The synthesized anatase TiO₂ microsphere based dye sensitized solar cells have high surface area with light scattering effect to enhance the photocurrent and conversion efficiency than the commercial P25 photoanode material. The power conversion efficiency of synthesized mesoporous TiO₂ microspheres and commercial P25 material is 4.2 and 2.7 % respectively. Therefore bimodal mesoporous anatase TiO₂ microsphere appears to be a promising and potential candidate for dye sensitized solar cells (DSSC) application.     

Porous microspheres of methoxy poly(ethylene glycol)-b-poly(?-caprolactone-co-d,l-lactide) prepared by a melt dispersion method

Surfactant-free biodegradable porous microspheres of methoxy poly(ethylene glycol)-b-poly(?-caprolactone-co-d,l-lactide) (MPEG-b-PCLDLL) diblock copolymers were prepared by a simple melt dispersion method in water at 80 °C with magnetic stirring. Any organic solvents and surfactants can be neglected for this method. Different CL/DLL ratios in the MPEG-b-PCLDLL were investigated for preparation of the porous microspheres. It was found that microsphere sizes decreased and surface pore sizes increased as the increasing DLL ratio. The pores were well interconnected throughout the microsphere matrices for all MPEG-b-PCLDLLs. The larger pore sizes can be obtained when the PEG was blended with diblock copolymer before preparation of porous blended microspheres. Possible mechanisms for formation of the porous microspheres with and without PEG blending were also proposed.     

磁性Fe3O4@SiO2@介孔SiO2空心微球的制备及漆酶固定化

磁性介孔二氧化硅复合材料作为酶固定化载体具有优异的酶固定化性能和良好的磁分离性能,受到国内外学术界广泛关注。本文在自制的β-FeOOH空心微球表面上包覆致密的SiO₂保护层,在酸性条件下以P123为模板剂,十六烷基三甲基溴化铵（CTAB）为辅助导向剂成功制备出了磁性β-FeOOH@SiO₂@介孔SiO₂空心复合微球,最后在还原气氛下煅烧得到Fe₃O₄@SiO₂@介孔SiO₂空心微球。结果表明,所制备的Fe₃O₄@SiO₂@介孔SiO₂微球空心结构未坍塌,具有规整的球形结构,介孔SiO₂壳层（平均厚度约为11nm）均匀地包覆在β-FeOOH@SiO₂中空微球表面。伴随着CTAB量的增加,微球的最可几孔径由4.30nm减小到3.19nm,比表面积从376m²/g升高到640m²/g,孔容从0.36cm³/g升高到0.56cm³/g。复合微球的饱和磁化强度为11.3emu/g,矫顽力为111.5Oe,外加磁场作用下可以实现样品的快速分离,且样品的再分散性良好。当介孔孔径为4.30nm时,Fe₃O₄@SiO₂@介孔SiO₂空心复合微球漆酶固定量高达234mg/g。固定化漆酶在不同pH、温度下的活性显著优于游离酶。     

ZnO/C nanocomposite microspheres with capsule structure for anode materials of lithium ion batteries

Well-designed nanostructures are very critical to the lithium-storage performance of electrode materials. To enhance the electrochemical performance of zinc oxide anode materials, a capsule structure, composed of carbon shell and its encapsulating ZnO microsphere, is designed. This capsule structured ZnO/C nanocomposite microspheres are prepared by a sol-gel method combined with two calcination processes. The carbon capsule shows great advantages of enhancing the structural stability of active material, reducing the formation of solid electrolyte interface (SEI) layer, and improving the conductivity of electrode. These factors are quite beneficial to the improvement of cycling stability, initial coulombic efficiency and rate capability. Consequently, capsule structured ZnO/C nanocomposite microspheres deliver an initial charge capacity of 790 mA h g⁻¹, an initial coulombic efficiency of 71%, and a reversible capacity retention of 63% after 100 cycles, all of which are higher than those of pure ZnO microspheres. These results suggest that the design of carbon encapsulated ZnO microsphere is quite effective for enhancing the lithium-storage properties and can also show general significance for developing high-performance electrode materials.