负载花椒精油的玉米醇溶蛋白-柑橘果胶乳液性能评价

目的 研发出一款新型的花椒精油Pickering乳液,为花椒精油Pickering乳液的制备和花椒精油应用场景的拓宽提供参考。方法 以花椒精油为油相,玉米醇溶蛋白-柑橘果胶复合纳米粒子为固体颗粒,制备花椒精油Pickering乳液。研究复合纳米粒子质量浓度(20、25、30、35、40 g/L)对Pickering乳液粒径、电位、微观结构、稳定性、流变特性等理化性能和抗氧化性能、抑菌性能等功能活性的影响。结果 随着复合纳米粒子浓度的提高,乳液的粒径呈先降后增趋势,ζ-电位绝对值、包埋率则呈先增后降趋势,当质量浓度为35 g/L的时候,乳液粒径最小为1 900.3 nm、ζ-电位和包埋率最大分别为32.7 mV、95%;此浓度下乳液贮藏稳定性最好,且具有优异的温度稳定性,在酸性(pH=2、3、4)和碱性环境(pH=8、9)下稳定性表现良好;所有乳液均显现出明显的剪切变稀行为,属于假塑性流体;在低频下乳液损耗模量大于储能模量,呈流体状态;相较于花椒精油,负载花椒精油的Pickering乳液的抗氧化性能和抑菌性能得到了显著提高。结论 复合纳米粒子质量浓度为35 g/L时制备的负载花椒精油Pickering乳液具有较好的稳定性、抗氧化和抑菌性能。     

TiO2纳米管包覆聚乙烯醇凝胶微球的制备及性能研究

通过水热法制备了二氧化钛纳米管(TNT),并使用油酸对其表面进行改性。以改性TNT为稳定剂,W/O型Pickering乳液为模板,通过冻融法制备了聚乙烯醇/二氧化钛纳米管(PVA/TNT)复合微球。采用高分辨透射电子显微镜、扫描电子显微镜、X射线能谱仪、热重分析仪等对改性TNT和PVA/TNT复合微球的结构及形貌进行了表征,选择亚甲蓝溶液作为模拟废水,对PVA/TNT复合微球光催化降解性能进行了研究。结果表明:改性TNT能很好地稳定W/O型Pickering乳液,以该乳液为模板可以制备出壳层包覆TNT、内核为聚乙烯醇凝胶的复合微球。PVA/TNT复合微球微球对亚甲蓝具有良好的吸附及光催化降解性能。     

有机无机杂化囊壳型微胶囊相变材料的研究进展

主要论述了传统微胶囊相变材料的的制备方法。介绍了以有机无机杂化材料为囊壳的微胶囊相变材料的优势,并总结了3种不同的制备方法,包括纳米粒子填充法,溶胶-凝胶法和Pickering乳液法。着重讨论了Pickering乳液在有机无机杂化囊壳微胶囊相变材料中的应用。     

双连续相微乳液制备连续孔聚丙烯酰胺凝胶

以十二烷基硫酸钠/甲苯/2-丁醇/盐水双连续微乳液相为模板,制备了3种组分双连续有机凝胶,水凝胶和有机/水杂化凝胶.12-羟基硬脂酸(12-HA)为有机凝胶剂.它们固定了水和油并使水和油微相共存于凝胶中.以静态光散射(SLS)测定了各双连续相微乳液的粒径,结果显示值在8～80nm.扫描电子显微镜观察了各凝胶的形貌,表明...     

反相微乳液法制备纳米凝胶的研究进展

纳米凝胶同时具有水凝胶及纳米材料的双面特性,作为药物载体在生物医药领域具有广阔应用前景。本文综述了反相微乳液法用于制备纳米凝胶的机理、特点,以及反相微乳液聚合和反相微乳液交联法在制备纳米凝胶方面的研究进展,并对反相微乳液法用于制备纳米凝胶中存在的问题进行了讨论。     

氧化石墨烯稳定的Pickering乳液及其聚合反应

通过改进的Hummers法制备氧化石墨烯(GO),以GO做稳定剂,甲基丙烯酸甲酯(MMA)为油相,制备了Pickering乳液,并研究了GO浓度、水相pH值对其稳定性的影响;通过加入引发剂成功进行了Pickering乳液聚合制备PMMA/GO复合微球,利用透射电镜对该复合微球的微观结构进行了表征。研究表明,GO稳定的Pickering乳液相比于SDBS稳定的普通乳液,液滴粒径更小且分散性更好;GO浓度对Pickering乳液的稳定性影响不大,但随其浓度的增加,Pickering乳液液滴尺寸变小,液滴更为分散;酸性连续相更有利于GO在油水界面的吸附而形成稳定的Pickering乳液,随着pH值增大,液滴尺寸逐渐变大,但碱性条件下乳液无法稳定存在;乳液聚合产物形貌为PMMA颗粒由GO片均匀包覆形成的复合微球,尺寸分布约200 nm左右。     

聚丙烯酰胺磁性水凝胶的互穿改性

将聚丙烯酸钠引入纳米Fe3O4/γ-甲基丙烯酰氧基丙基三甲氧基硅烷(TPM)/聚丙烯酰胺(PAM)磁性复合水凝胶体系中,制备了互穿聚合物网络(IPN)超强磁性水凝胶。采用透射电镜(TEM)、激光粒度分析仪、扫描电镜(SEM)、压缩试验机和样品振动磁强计对Fe3O4纳米粒子的粒径、Pickering乳液的结构及水凝胶的结构与性能进行了测试与表征。结果表明,IPN改性水凝胶在保持原复合水凝胶优异性能的基础上,其断面结构比未改性的更为规整,水凝胶的内部缺陷减少;改性水凝胶的抗压强度可达2.8MPa以上,远高于未改性水凝胶的强度;改性水凝胶需要约50min达溶胀平衡,平衡时的溶胀率为24.9;改性后的水凝胶中Fe3O4纳米粒子的磁性并未受到影响。     

立方笼型倍半硅氧烷稳定的乳液聚合及其Pickering效应

以立方笼型八甲基丙烯酰氧丙基倍半硅氧烷(CMSQ-T8)纳米粒子为稳定剂,苯乙烯(St)为聚合单体,在添加少量有机乳化剂十二烷基磺酸钠(SDS)的条件下制备了稳定的聚苯乙烯/立方笼型倍半硅氧烷(PS/CMSQ-T8)乳液。利用透射电子显微镜、动态光散射仪、傅里叶变化红外光谱分析和热重分析等对乳液微球的粒径和结构进行了表征,并研究了CMSQ-T8含量对微球粒径和乳液稳定性的影响。结果表明,PS/CMSQ-T8乳液粒径均一,乳液胶粒具有明显的核壳结构,且粒径和Zeta电位随CMSQ-T8含量的增多呈先减小后增大的趋势。CMSQ-T8位于PS表面形成壳层,起到稳定乳液的作用,具有Pickering效应,且可能与核壳界面处的苯乙烯发生了共聚而增强乳液的稳定性。     

SiO2气凝胶微球的雾化制备及表征

研究硅溶胶的雾化方法和形成油包水的乳化体系,在乳化体系中加入凝胶剂制备SiO2湿凝胶微球。制得的湿凝胶微球在常温常压下老化3d后用过滤的方法分离湿凝胶微球和油相;用正己烷清洗微球表面的油和杂质,用乙醇除去湿凝胶微球内部的水;最后,用超临界CO2的方法干燥湿凝胶微球得到SiO2气凝胶微球。研究结果表明,该方法最大的优点是可以大规模化制备气凝胶微球,制得的气凝胶微球直径<50μm,大部分集中在15～35μm之间。SiO2气凝胶微球具有明显的介孔材料特征,孔径为10nm左右,比表面积高达846.14m2/g,堆积密度约为221kg/m3。     

微乳液技术在纳米材料合成中的应用

微乳液是由表面活性剂、助表面活性剂在有机溶剂或水中形成的热力学稳定的各向同性的单分散体系,其分散质点为纳米级。它为纳米粒子的制备提供理想的模板和微环境。本文介绍了纳米材料、微乳液以及运用微乳液技术制备纳米材料以及该法的优点和和应用范围。     

Interparticle photo-cross-linkable Pickering emulsions for rapid manufacturing of complex-structured porous ceramic materials

A new series of Pickering emulsions that can be photo-cured by interparticle photo-cross-linking reactions using small amounts of multifunctional acrylate (MA) monomers is proposed to rapidly manufacture complex-structured porous ceramic materials. In our new process, water in oil (w/o) Pickering emulsion was designed by vigorous mixing of water and polyethyleneimine partially complexed with oleic acid (PEI–OA)-stabilized SiO₂/toluene suspension containing small amounts of MA and a photo-radical initiator. Ultraviolet light irradiation to this w/o Pickering emulsion induced the formation of interparticle photo-crosslinks, which resulted in successful photocuring by photo-radical polymerization of MA and the Michael addition reaction between the polymerized MA and PEI–OA on the particles in the oil phase. We further applied the newly designed photo-curable Pickering emulsion and demonstrated that SiO₂ components with pores related to the dispersed aqueous phase and complexed outer structures could be shaped via silicone molding or a hybridized approach of photocuring and green machining. Because of the reduced amounts of MA used, the porous SiO₂ green components could be heat-treated using rapid heating profiles without any structural collapse for dewaxing and partial sintering.     

Gold nanoparticles bound on microgel particles and their application as an enzyme support

Submicron-sized poly(N-isopropyl acrylamide)/polyethyleneimine core-shell microgels were prepared in aqueous media by using tert-butyl hydroperoxide (TBHP) as an initiator, and then the gold nanoparticles (～8?nm) were formed on the surface of the microgels. The amino groups on the polyethyleneimine (PEI) chains act as the binder for the assembly of the gold nanoparticles/microgel complex. In aqueous media the microgels are highly stable with the gold nanoparticles on their extended PEI chains, and this multi-scale nanoparticle complex can be recovered from water and redispersed in water. The nanogold/microgel particles were conjugated with the enzymes horseradish peroxidase (HRP) and urease. It is found that under identical assay conditions the enzyme/nanogold/microgel systems exhibit enhanced biocatalytic activity over free enzymes in solution, especially at lower enzyme concentrations. In addition, compared to free HRP, the HRP/nanogold/microgel systems show higher activity at varied pHs and temperatures, as well as higher storage stability. Thus the novel nanogold/microgel particles can serve as an excellent support for enzymes.     

Formation of Janus TiO2 nanoparticles by a pickering emulsion approach applying phosphonate coupling agents

Anisotropic surface modification of TiO2 nanoparticles was achieved applying a Pickering emulsion approach. TiO2 nanoparticles were prepared by sol-gel routes which allowed an excellent control over their size and morphology. The obtained colloids were further used as stabilizers in the formation of oil-in-water Pickering emulsion. For reasons of comparison, also commercially available titanium dioxide nanoparticles (Evonik AEROXIDE TiO2 P25) were used in the functionalization experiments. An organophosphorus coupling agent present in the oil phase coordinated to the surface of the anatase nanoparticles. In such a way an anisotropic surface modification of the particles was achieved which increased the stability of the Pickering emulsion. Spectroscopic studies revealed the presence of organophosphorus coupling agents which exhibited a covalent bonding to the surface of the particles. Thermogravimetric analyses confirmed a lower surface coverage of the particles modified in emulsion compared to those modified in suspension. Reactions of organophosphorus coupling agents containing an additional methacrylate group applying an organic monomer (methyl methacrylate) as the oil phase of the Pickering emulsion resulted in hybrid TiO2@polymer spheres. Spectroscopic characterization of the resulting particles revealed that the phosphonates were coordinated to the TiO2 surface and at the same time copolymerized with the MMA within the oil droplet. Morphological investigations of the isolated final product showed that the material was composed of polymer spheres with the stabilizing TiO2 nanoparticles on their surface.     

Control of Particle Adsorption for Stability of Pickering Emulsions in Microfluidics

Studying the stability of Pickering emulsion is of great interest for applications including catalysis, oil recovery, and cosmetics. Conventional methods emphasize the overall behavior of bulk emulsions and neglect the influence of particle adsorbing dynamics, leading to discrepancies in predicting the shelf‐life of Pickering emulsion–based products. By employing a microfluidic method, the particle adsorption is controlled and the stability of the Pickering emulsions is consequently examined. This approach enables us to elucidate the relationship between the particle adsorption dynamics and the stability of Pickering emulsions on droplet‐level quantitatively. Using oil/water emulsions stabilized by polystyrene nanoparticles as an example, the diffusion‐limited particle adsorption is demonstrated and investigated the stability criteria with respect to particle size, particle concentration, surface chemistry, and ionic strength. This approach offers important insights for application involving Pickering emulsions and provides guidelines to formulate and quantify the Pickering emulsion–based products.     

Design of multicomponent microgels by selective deposition of nanomaterials

In the present paper a method for the targeted deposition of different nanomaterials on aqueous microgels is described. In the first stage poly(3,4-ethylenedioxythiophene) (PEDOT) nanorods are introduced into the microgel structure by in situ oxidative polymerization. In the second stage hydrogen tetrachloroaurate is used to transform PEDOT chains to an oxidized state in the microgel structure, leading to the fixation of chloroaurate anions on the surface of the PEDOT nanorods. The reduction of chloroaurate ions induces the formation of gold nanoparticles (AuNPs) predominantly located on the PEDOT surface. Obtained microgel/PEDOT/AuNP hybrid particles with different nanoparticle loadings exhibit superior colloidal stability and temperature sensitivity. The microgel/PEDOT/AuNP hybrid microgels exhibit extraordinary catalytic activity in aqueous media.     

Injectable Granular Hydrogels with Multifunctional Properties for Biomedical Applications

Injectable hydrogels are useful for numerous biomedical applications, such as to introduce therapeutics into tissues or for 3D printing. To expand the complexity of available injectable hydrogels, shear‐thinning and self‐healing granular hydrogels are developed from microgels that interact via guest–host chemistry. The microgel properties (e.g., degradation, molecule release) are tailored through their crosslinking chemistry, including degradation in response to proteases. When microgels of varied formulations are mixed, complex release and degradation behaviors are observed, including after injection to permit cellular invasion.     

凸棒颗粒稳定的橄榄油／水型Pickering乳状液的制备条件及形成机理研究

选取凹凸棒作为乳化剂,系统研究pH、颗粒浓度、油相体积分数以及不同价态盐对橄榄油／水型Pickering乳状液稳定性的影响,结果表明,体系pH在4～9范围内可制备出稳定的乳状液;颗粒浓度的提高可增强乳液的分层和聚结稳定性;乳液液滴直径随油相体积分数的增加先增大后减小;无机盐的引入不会对乳液相及水相的体积产生影响,但对乳液液滴的尺寸分布影响显著,其中NaCl浓度的增加有利于乳状液液滴数均直径的增加,而CaCl2浓度增加时,乳状液液滴数均直径呈现先增大后减小的变化趋势。研究表明,凹凸棒可作为一种新型纳米乳化剂应用于绿色乳状液的制备。     

Fibrillized peptide microgels for cell encapsulation and 3D cell culture

One of the advantages of materials produced by self-assembly is that in principle they can be formed in any given container to produce materials of predetermined shapes and sizes. Here, we developed a method for triggering peptide self-assembly within the aqueous phase of water-in-oil emulsions to produce spherical microgels composed of fibrillized peptides. Size control over the microgels was achieved by specification of blade type, speed, and additional shear steps in the emulsion process. Microgels constructed in this way could then be embedded within other self-assembled peptide matrices by mixing pre-formed microgels with un-assembled peptides and inducing gelation of the entire composite, offering a route towards multi-peptide materials with micron-scale domains of different peptide formulations. The gels themselves were cytocompatible, as was the microgel fabrication procedure, enabling the encapsulation of NIH 3T3 fibroblasts and C3H10T-1/2 mouse pluripotent stem cells with good viability.     

Hybrid Organic–Inorganic Colloidal Composite ‘Sponges’ via Internal Crosslinking

An effective method for the generation of hybrid organic–inorganic nanocomposite microparticles featuring controlled size and high structural stability is presented. In this process, an oil‐in‐water Pickering emulsion is formed using hydrophilic amine‐functionalized silica nanoparticles. Covalent modification using a hydrophobic maleic anhydride copolymer then alters nanoparticle wettability during crosslinking, causing a core‐shell to nanocomposite structural reorganization of the assemblies. The resulting porous nanocomposites maintain discrete microparticle structures and retain payloads in their oil phase even when incubated in competitive solvents such as ethanol.     

超疏水FeNi2O4/甲基丙烯酸乙烯酯-二乙烯苯共聚物多孔材料的制备及其油水分离应用

为了应对日益频发的溢油事故,实现含油水体的净化,通过高内相Pickering乳液模板法制备了FeNi₂O₄掺杂的甲基丙烯酸乙烯酯-二乙烯苯共聚物多孔材料。采用FTIR、SEM、TGA、VSM、接触角测量仪、静态压汞仪、万能试验机等对材料结构与性能进行表征与分析。结果表明,材料具有三维分级多孔结构,孔径主要分布于3 μm及6~14 μm且大孔孔径可调节。材料热稳定性好,初始热分解温度最高达300℃。FeNi₂O₄纳米粒子的引入不仅提升了乳液稳定性,也赋予材料磁响应性。材料具有良好的疏水亲油性,水接触角达151°、滚动角为5°、油接触角为0°,吸油速率快,并具有良好的重复利用性和优异的油水吸附选择性,对多种油品及有机溶剂的饱和吸附倍率达40.80~93.08 g·g?1,且保油率均在90%以上。探究了材料的孔结构调控,发现,改变乳液的内相比可以调节材料的大孔分布、孔隙率、密度、比表面积、吸油倍率和力学性能。综上说明:超疏水FeNi₂O₄/甲基丙烯酸乙烯酯-二乙烯苯共聚物多孔材料可以高效分离水中油污,对水体环境的治理与净化具有现实意义。