皮克林乳液技术在防晒产品中应用的研究进展

从TiO_2颗粒稳定的Pickering乳液、TiO_2和ZnO颗粒稳定的Pickering乳液和Pickering乳液聚合法制备复合防晒微球体等方面,对Pickering乳液技术在防晒产品中的应用进行了阐述,最后对该技术在防晒领域的发展方向进行了展望。     

Pickering乳液在药物载体制备方面的研究进展

Pickering乳液具有成本低、稳定性好、毒性小等优点,广泛应用于化妆品、食品、医药等方面。利用Pickering乳液制备药物载体操作简单,可改善难溶药物的溶出,对药物具有一定的缓释效果,其在药物载体方面具有广阔的发展前景。本文综述了近些年Pickering乳液在药物载体方面的研究进展,首先简要介绍了药物缓释技术及Pickering乳液性质;然后重点分析了不同固体粒子稳定的Pickering乳液在载药微球制备中的研究;还探讨了Pickering乳液在制备载药凝胶、载药多孔支架以及载药乳剂等方面的应用;最后对Pickering乳液制备药物载体方面作出展望,随着该技术相关研究的发展和成熟,药物载体的稳定性、生物相容性等问题的突破,利用Pickering乳液制备药物载体的方法技术将更有利于药物载药体系的发展。     

Alg@TiO2微球稳定的Pickering乳液用做防晒乳成分的研究

为了开发一种兼具防晒功能和乳液稳定性的防晒乳配方,设计了一种负载二氧化钛纳米颗粒的海藻酸钙微球（Alg@Ti O₂微球）来稳定Pickering乳液,用作防晒乳成分。考察了油水比和微球含量对Pickering乳液的影响,探究了乳液类型,并进行了长期保存稳定性测试。结果表明,Alg@Ti O₂微球形状为球形,大小为2～6μm;Alg@Ti O₂微球中二氧化钛纳米颗粒含量为43%;微球与油水的三相接触角为120°;当油水比为1∶1,微球含量为3%（w/%）时,稳定的白油/水体系Pickering乳液为油包水型（W/O型）,经100 d室温保存后乳液状态保持稳定。通过紫外吸收实验,和包括市售防晒乳在内的其他3种防晒乳相比,该Pickering乳液具有优异的防晒性能。通过皮肤表面清洗实验,该Pickering乳液具有易清洗的特性。     

掺氮TiO_2纳米颗粒稳定的Pickering乳液制备及其触发酶反应

利用烷基硅烷接枝的掺氮TiO_2纳米颗粒稳定W/O型Pickering乳液,研究了TiO_2掺氮量对成乳的影响以及乳液的可见光响应性能,并将其作为微反应器应用于触发脲酶催化尿素生成碳酸铵的反应中。结果表明:在可见光照射下,烷基硅烷接枝的掺氮TiO_2纳米颗粒表面由疏水变为亲水,可引发乳液液滴聚并以及液滴内酶促反应发生。     

SCL@SiO2纳米颗粒制备及其稳定Pickering乳液的研究

用共轭亚油酸钠（SCL）在SiO2纳米颗粒表面吸附,得到表面改性的SiO2纳米颗粒,然后在80 oC条件下通过热聚合引发SCL分子自交联,从而稳定SCL@SiO2纳米颗粒的SCL层并改善表面润湿性。通过Zeta电位表征手段证实SCL吸附在SiO2纳米颗粒表面。以SCL@SiO2纳米颗粒作为单一乳化剂制备液体石蜡的Pickering乳液,结果表明该Pickering乳液比传统乳液更稳定。由于SCL@SiO2纳米颗粒的SCL层比简单吸附脂肪酸的SiO2改性颗粒更稳定,且粒径会随着pH的变化而发生变化,因此由其稳定的Pickering乳液具有一定的pH响应性。     

Pickering乳液聚合技术在合成功能材料方面的研究进展

Pickering乳液聚合技术是在微纳米固体颗粒稳定的乳液基础上进行聚合的一种新型反应技术，在合成功能复合材料的应用方面获得了特别的关注。介绍了Pickering乳液的稳定机理和基于Pickering乳液聚合技术合成的复合材料的分类，并着重综述了其在制备新型载药材料、吸附分离材料和传感检测材料等方面的研究现状，同时还展望了其发展前景。     

疏水改性核壳结构颗粒对Pickering乳液的稳定作用

为了探究固体颗粒对乳液的稳定作用,采用双亲染料分子罗丹明B对核壳结构的Fe_3O_4@SiO_2纳米颗粒进行疏水改性,并将改性后的纳米颗粒作为稳定剂制备Pickering乳液。通过Zeta电位、FTIR、XRD、SEM、接触角测量、光学显微镜、电导率仪对Fe_3O_4@SiO_2纳米颗粒以及Pickering乳液的结构、形貌和性能进行表征与分析,结果表明:制备的纳米颗粒粒径小,约为150 nm,为单分散球形核壳结构;罗丹明B成功修饰到Fe_3O_4@SiO_2纳米颗粒表面,改性后颗粒接触角由30°增加至120°;随乳化剂颗粒质量浓度的增加,制备的乳液液滴的粒径减小。另外,所得Pickering乳液具有良好的磁场响应性,可通过外加磁场实现对乳液稳定性的可逆调控,且此过程可重复3次以上。     

海藻酸辛酰胺协同纳米二氧化硅稳定Pickering乳液

采用辛胺疏水改性海藻酸钠合成了具有两亲性的高分子表面活性剂海藻酸辛酰胺(OAAD),并将其与SiO2纳米颗粒协同制备了稳定的Pickering乳液。通过FTIR、1HNMR、表面张力、荧光光谱、动态光散射、接触角测量、光学显微镜分别对OAAD、OAAD/SiO2纳米颗粒水分散体系和Pickering乳状液的性能进行了表征。结果表明,辛胺氨基成功接枝到海藻酸钠(SA)分子链上,OAAD界面张力较SA降低、临界聚集质量浓度为0.60 g/L,表现出良好的两亲性。将OAAD吸附在SiO2纳米颗粒表面形成的水分散体系用于稳定Pickering乳液时,发现随着OAAD质量浓度增加,SiO2纳米颗粒润湿性增加,Zeta电位减少,粒径增加;而乳液的粒径则逐渐减少,稳定性增强,其机理经初步分析为,当一定浓度的OAAD吸附在SiO2纳米颗粒表面,可导致颗粒间絮凝,从而在油水界面形成网络结构式界面膜,有利于提高Pickering乳液的稳定性。     

基于纤维素纳米晶稳定的亚微米Pickering乳液制备

与传统表面活性剂稳定的乳液相比,固体纳米颗粒稳定的Pickering乳液具有较强的界面稳定性、多功能性、低毒性等优势,在生物医药领域具有较大的应用潜力。而相较于尺寸较大的微米级Pickering乳液,亚微米Pickering乳液具有更大的比表面积、更有效的递送效率,有望进一步拓展Pickering乳液在生物医药领域的应用。但由于Pickering乳液的制备影响因素众多,且相互制约,刚性的固体颗粒难以在较小的有限油水界面排布,增加了亚微米Pickering乳液的制备难度。本工作以制备稳定的亚微米Pickering乳液为研究目标,采用具有良好生物相容性的天然多糖–纤维素纳米晶(CNCs)为颗粒乳化剂,角鲨烯作为油相,考察了颗粒浓度、油水比例、水相成分、超声时间及频率对Pickering乳液粒径分布及稳定性的影响,最终得到了具有良好的储存稳定性和抗离心稳定性的粒径为638.7?8.40 nm的亚微米Pickering乳液(CNCs-PE)。通过激光共聚焦显微镜证实了CNCs吸附在油水界面,形成了Pickering乳液结构。利用CCK-8法评价了CNCs和CNCs-PE的细胞毒性,结果表明,两者都具有良好的细胞安全性。此外,将其用于吸附模型抗原OVA,吸附率达到约80%,且肌肉注射部位的切片结果也表明其注射安全性良好。此结果为亚微米Pickering乳液进一步研究提供了参考,并有望拓展CNCs稳定的亚微米Pickering乳液在生物医药领域的应用。     

SCL@SiO_2纳米颗粒的制备及其稳定的Pickering乳液

用共轭亚油酸钠(SCL)在SiO_2纳米颗粒表面吸附,得到表面改性的SiO_2纳米颗粒,然后在80℃下通过热聚合引发SCL分子自交联,从而稳定SCL@SiO2纳米颗粒的SCL层并改善其表面润湿性。通过Zeta电位、FTIR、DLS、TG和DTG对材料进行了表征。结果显示:SCL物理吸附在SiO_2纳米颗粒表面。以SCL@SiO2纳米颗粒作为单一乳化剂制备液体石蜡的Pickering乳液,结果表明:该Pickering乳液在制备一个月后外观基本不发生变化,而传统乳液出现明显破乳现象。热重分析结果显示:SCL@SiO2纳米颗粒的SCL层比简单吸附脂肪酸的SiO_2改性颗粒更稳定,且粒径会随着pH的减小而增大(11～16 nm),因此,由SCL@SiO2纳米颗粒稳定的Pickering乳液粒径(15～29μm)也具有一定的pH响应性。     

Synthesis of Polystyrene/Hydrophobic SiO2 Composite Particles via Oil‐in‐Water Pickering Emulsion Polymerization

The aim of this work is to present a facile Pickering emulsion polymerization method for the synthesis of submicron polystyrene/SiO₂ core/shell composite particles. The commercial hydrophobic SiO₂ nanoparticles were used as stabilizing agent for creating a stable oil‐in‐water emulsion. Although the adsorption of hydrophobic SiO₂ nanoparticles in the emulsion system was unfavorable in terms of thermodynamics, by ultrasound treatment, self‐assembly of hydrophobic SiO₂ nanoparticles effectively stabilized oil‐in‐water Pickering emulsions during polymerization. Using 3 wt.% SiO₂ nanoparticles (based on styrene monomer) and 1:10 volume ratio of styrene monomer:water, the composite particles having average size of 790 nm and relatively narrow particles distribution were produced. With decreasing the volume ratio, smaller composite particles were created. Results from scanning electron microscope revealed that SiO₂ nanoparticles were located exclusively at the surface of the polystyrene latex particles. The SiO₂ content, determined by thermogravimetric analysis, was 12.6 wt.% in the composite particles. The route reported here may be used for the preparation of other composite nanostructures. POLYM. ENG. SCI., 59:E195–E199, 2019. © 2018 Society of Plastics Engineers     

基于纳米氢氧化铝颗粒的Pickering乳液制备

以异丙醇铝为原料,采用醇盐水解?水热法制备勃姆石型纳米氢氧化铝颗粒,优化制备条件;以所制颗粒为稳定剂、角鲨烯为油相,通过超声破碎法制备Pickering乳液,考察了颗粒浓度、水相成分、超声时间及功率对Pickering乳液粒径及稳定性的影响。结果表明,水热温度200℃、水热时间2 h条件下,可制得结晶度高且均一的勃姆石型纳米氢氧化铝颗粒,平均粒径为55.70?9.20 nm,多分散性指数(PDI)为0.187?0.011;所制Pickering乳液平均粒径为1870?55 nm,PDI=0.120?0.010,可在室温下稳定储存120 d以上,且生物相容性良好,有望应用于生物医药领域。     

Growth mechanism and pH-regulation characteristics of composite latex particles prepared from Pickering emulsion polymerization of aniline/ZnO using different hydrophilicities of oil phases

A Pickering emulsion polymerization of aniline, using different hydrophilicities of oil phases, was stabilized by ZnO nanoparticles and performed to synthesize composite latex particles of polyaniline/ZnO. Ammonium peroxydisulfate (APS) was used as an oxidizing agent. The morphologies and growth mechanisms of the resulted composite latex particles were studied. The pH-regulation capacity of the composite latex particles was discussed. When toluene was used as the oil phase, the composite latex particles showed hollow structure, irregular morphology, and hundreds of nanometer in size. It was ascribed to the polymerization of aniline on the interfaces of droplets/water. ZnO nanoparticles, with 50-100 nm in size, acted as surfactants to stabilize the emulsion. When THF was used as an oil phase, the composite latex particles showed spherical morphology and enwrapping ZnO nanoparticles. It was attributed to the homogeneous nucleation of polyaniline in the aqueous phase. ZnO nanoparticles acted as templates for the polyaniline particles. The stability of the Pickering emulsion polymerization was affected by the volume ratio of the oil phase to water. The aqueous solution with pH 3-9 could simply be regulated to about pH 7 by the composite latex particles. It was contributed by the dissolution of ZnO nanoparticles and doping-dedoping of polyaniline in the acidic and alkaline aqueous solutions.     

Influence of Nanoparticles and Drop Size Distributions on the Rheology of w/o Pickering Emulsions

The rheological behavior of particle/oil suspensions and w/o Pickering emulsions consisting of water, 1‐dodecene and different fumed silica nanoparticles was investigated. The particles varied in hydrophobicity and specific surface area. The influence of particle concentration and water content on rheology was determined and the emulsion drop size distributions were examined. Emulsions with different drop sizes were created by either varying the particle concentration or the water content. It was found that the particles in the continuous oil phase and not the drop size distribution seem to be the major influencing factor on the Pickering emulsion rheology.     

高亲水性纳米二氧化硅颗粒稳定Pickering乳液

用未修饰的高亲水性纳米二氧化硅颗粒(SiO2 NPs)在其等电点附近制备Pickering乳液。结果表明,等电点(pH 2.7)条件下SiO2 NPs借助高能均质与油水界面剧烈混合,并在范德华引力的驱动下以弱吸附的状态在界面处负载,从而稳定得到O/W型Pickering乳液。增加SiO2 NPs的浓度或减小油相体积分数可提高单位油滴界面的颗粒负载率,增大连续相黏度并促进乳液液滴之间形成三维网络结构从而提高乳液稳定性。通过调节连续相的pH以促进SiO2 NPs表面的硅烷醇发生质子化与去质子化的转变,实现乳液多次pH响应循环。     

海藻酸辛酰胺的制备及其协同氨基SiO2纳米粒稳定液体石蜡/水乳液的研究

以辛胺为疏水改性剂,采用酰化法制得具有两亲性的海藻酸辛酰胺(ACA)。将ACA与采用修正Stber法制备的氨基二氧化硅(SiO_2-NH_2)纳米粒混合,在超声的作用下制得O/W型Pickering乳液。通过FT-IR,~1H NMR和荧光光谱对ACA的结构和性能进行表征。并采用激光粒度和Zeta电位分析仪、接触角测量仪和光学显微镜探究了ACA,SiO_2-NH_2及其协同水分散体系的胶体性能和相应的Pickering乳液的形貌。结果表明:ACA的取代度为0.29,在0.15 mol/L Na Cl水溶液中的临界聚集浓度(cac)为0.42 g/L,表现出较强的两亲性能。ACA通过静电作用力成功地吸附于SiO_2-NH_2纳米粒上,使水动力学粒径只有155 nm的SiO_2-NH_2纳米粒增长至386 nm,Zeta电位由+22.2 mV转变为-30.7 mV,在水溶液中能够表现出良好的稳定性。吸附于SiO_2-NH_2纳米粒表面的ACA可以抑制无机纳米粒的聚沉,而游离的ACA形成的胶束结构的疏水内腔能够增溶油滴,减少小油滴的聚并。光学显微镜中出现了粒径较大的Pickering乳液液滴和粒径较小的传统乳液液滴共存的现象,当ACA质量浓度在0.5 cac~1.0 cac时,2种乳液共存现象最为显著。     

用于细菌生物膜感染治疗的Pickering乳液制备

人体常见的持续性感染疾病通常与细菌生物膜有关。使抗菌药物高效渗透到细菌生物膜内部并杀伤细菌是治疗细菌生物膜感染的关键。本研究构建了一种具有强渗透性和杀菌性的Pickering乳液。该Pickering乳液以天然抗菌剂丁香油为油相内核,以稳定吸附在油水界面的正电壳聚糖纳米颗粒(CS-NPs)为外壳,通过与负电胞外基质的静电相互作用,实现对细菌生物膜的强渗透。制备的壳聚糖纳米颗粒平均粒径为590.30±3.90 nm,多分散性指数PDI为0.125±0.003,平均电势为15.60±0.40 mV。Pickering乳液平均粒径为2312±53 nm,多分散性指数PDI为0.137±0.013,平均电势为26.45±0.55 mV。细菌生物膜渗透实验与杀菌性能实验表明,该Pickering乳液对细菌生物膜有较强的渗透能力,并能有效地杀伤细菌。该Pickering乳液有望用于治疗人体与细菌生物膜相关的持续性感染。     

软模板法石墨烯气凝胶的可控制备及其吸油性能

以环己烷为油相，氧化石墨烯（GO）为稳定剂，采用Pickering乳液法制备石墨烯气凝胶，利用电子显微镜对Pickering乳液进行表征，利用扫描电镜（SEM）、傅里叶红外光谱（FTIR）、拉曼光谱（Raman）、X射线衍射（XRD）对制得的石墨烯气凝胶进行表征。对比Pickering乳液的液滴大小与气凝胶的孔径大小可知，通过软模板法实现了对气凝胶的孔径控制，通过控制均质机的转速来调控气凝胶的孔径大小，当均质机转速分别为10000r/min、12000r/min和15000r/min时，所得石墨烯气凝胶的孔径分别为45μm、35μm和30μm左右，通过调节油水比实现了气凝胶的密度与孔隙率的控制，油水比越大，所得气凝胶的密度越小，孔隙率越大，通过延长还原时间可增强石墨烯气凝胶的机械性能。将所得气凝胶用于油品的吸附，可快速吸附水上浮油及水底重油，而且几乎不吸附水；对同一油品而言，气凝胶的吸附能力与其制备时的油水比呈正相关，采用挤压的方式实现石墨烯气凝胶的循环利用，经过10次循环再生后气凝胶的吸附能力仅有15%的损失。     

Chitosan nanoparticles as particular emulsifier for preparation of novel pH-responsive Pickering emulsions and PLGA microcapsules

In this work, we describe a novel and simple method for fabricating biocompatible microcapsules. Chitosan colloidal nanoparticle-coated micrometer-sized poly(lactic-co-glycolic acid) (PLGA) microcapsules were fabricated via a combined system of “Pickering-type” emulsion route and solvent volatilization method in the absence of any molecular surfactants. Stable oil-in-water emulsions were prepared using chitosan colloidal nanoparticles as a particulate emulsifier and a dichloromethane (CH₂Cl₂) solution of PLGA as an oil phase. Moreover, this stable emulsion present a good pH-responsive characteristic. The uncross-linked chitosan nanoparticles coated PLGA microcapsules were fabricated by the evaporation of CH₂Cl₂ from the emulsion, and the cross-linked chitosan nanoparticles coated PLGA microcapsules were prepared by cross-linking with glutaraldehyde and evaporation of CH₂Cl₂. The two types of microcapsules were characterized in terms of size, morphology using scanning electronic microscope (SEM), optical microscope, and so on. These observations confirm the robust nature of these cross-linked microcapsules. Moreover, a possible mechanism for the formation of these microcapsules was proposed. The combined system of Pickering emulsion and solvent volatilization opens up a new route to fabricate a variety of microcapsules.