刺激响应型Pickering乳液的制备及应用进展

固体纳米颗粒代替传统表面活性剂作为乳化剂稳定的Pickering乳液具有抗聚结性高、环境友好、成本较低等优点,在多个领域具有广阔应用前景.通过适当刺激精确调控乳液稳定性及构建响应型Pickering乳液的研究引起广泛关注.综述了多种刺激响应型Pickering乳液的构建、调控及应用.首先,阐述了Pickering乳液的...     

环境响应型Pickering乳液的研究进展

本文主要介绍了Pickering乳液及其稳定机理,pH、温度、磁场、电场等环境响应型Pickering乳液的研究进展,并对Pickering乳液未来的发展方向进行了展望。     

刺激响应型Pickering乳液的制备及应用研究进展

固体纳米颗粒代替传统表面活性剂作为乳化剂稳定的Pickering乳液具有高抗聚结性、环境友好性、成本较低等优点,在多种领域具有广阔应用前景。通过适当刺激精确调控乳液稳定性及构建响应型Pickering乳液的研究引起广泛关注。该文详细综述了多种刺激响应型Pickering乳液的构建、调控及其应用。首先阐述了Pickering乳液的稳定性影响因素和备固体颗粒乳化剂表面改性技术;继而介绍了多种刺激响应性Pickering乳液的响应机理和性能;最后综述了Pickering乳液的应用研究;分析展望了Pickering乳液研究应用中存在的问题和发展前景。     

凹凸棒石在Pickering乳液制备中的应用研究进展

凹凸棒石因具有独特的一维纳米棒状形貌、纳米孔道结构、天然的负电性和良好的水分散性等特点,在Pickering乳液的制备和应用方面受到广泛关注。在介绍凹凸棒石结构特点和理化性质的基础上,综述了凹凸棒石在Pickering乳液制备中的应用研究进展,以期为凹凸棒石及其它黏土矿物稳定Pickering乳液的机理研究及应用拓展提供较全面信息。     

Pickering乳液在功能高分子中的应用研究进展

院综述了Pickering乳液在功能高分子中的应用研究,介绍了Pickering乳液制备Janus粒子和刺激响应性高分子的方法,提出了Pickering聚合制备功能高分子材料面临的问题,并对其发展前景进行了展望。     

纳米纤维素在Pickering乳液制备中的应用研究进展

纳米纤维素因具有来源广、可降解、可再生、稳定性强等特点,逐渐成为制备Pickering乳液的研究热点。阐述了Pickering乳液的稳定机理和影响因素,综述了近些年纳米纤维素制备Pickering乳液的研究进展,以及纳米纤维素稳定Pickering乳液的应用现状,以期为纳米纤维素在Pickering乳液中的研究与应用提供参考。     

环境响应型Pickering乳液的研究进展

环境响应型智能水凝胶能够对外界环境温度、pH值、CO2气体、磁场等变化产生显著的体积或其他特性的变化,且其性质和结构与生物组织类似,有望应用于药物运输、细胞封装、组织工程等领域,引起了广泛的关注.近年来,采用环境响应型粒子作为Pickering乳液的乳化剂,制备出一种新型高效的乳剂成为研究热点.介绍了环境响应型粒子稳定乳液的研究进展,最后提出了未来食品和药物运输等领域环境响应型Pickering乳液的研究趋势.     

双重刺激响应型pickering乳液研究进展

Pickering乳液因其极强的稳定性、良好的生物相容性和对环境友好等特点在众多领域有着广泛应用.虽然乳液必须具有良好的稳定性,但实际应用中通过适当的触发机制使其能够实现快速破乳也是非常重要的.响应型Pickering乳液由于在特定因素刺激下可以轻易实现可逆乳化-破乳成为近些年研究的热点.早期研究学者主要研究单一刺激因...     

Pickering乳液在菊酯类农药水乳液中的应用

通过十六烷基三甲基溴化铵(CTAB)对纳米二氧化硅(Si O2)进行原位疏水化,将其作为乳化剂,以正庚烷作为油相,成功制备了氯菊酯农药水乳液。通过表观照片、分水率、显微镜、流变仪等表征手段测试了Pickering乳液的稳定性和流动性。对制备过程中乳化剂用量、油水比等进行优化,确定了油水比(体积比)为7∶3、CTAB浓度为0. 1 m M、Si O2浓度为0. 7%为乳液最佳制备工艺。所制备的农药水乳液具有良好的应用性能。     

Pickering乳液的研究进展

简要介绍了Pickering乳液的稳定机理,即机械阻隔机理和三维黏弹粒子网络机理。从球形固体颗粒稳定的乳液、片层状固体粒子稳定的乳液以及不同环境响应型乳液(如pH、温度、电场、磁场)等方面对目前Pickering乳液的研究现状进行了综述,并概述了Pickering乳液在乳液聚合、功能材料的制备、药物释放和催化剂的分离回收等方面的应用研究,最后对其发展方向进行了展望。     

pH-triggered phase inversion and separation of hydrophobised bacterial cellulose stabilised Pickering emulsions

The pH-triggered transitional phase behaviour of Pickering emulsions stabilised by hydrophobised bacterial cellulose (BC) is reported in this work. Neat BC was esterified with acetic (C₂–), hexanoic (C₆–) and dodecanoic (C₁₂–) acids, respectively. We observed that C₆– and C₁₂–BC stabilised emulsions exhibited a pH-triggered reversible transitional phase separation. Water-in-toluene emulsions containing of 60 vol.% dispersed phase stabilised by C₆– and C₁₂–BC were produced at pH 5. Lowering the pH of the aqueous phase to 1 did not affect the emulsion type. Increasing the pH to 14, however, caused the emulsions to phase separate. This phase separation was caused by electrostatic repulsion between modified BC due to dissociable acidic surface groups at high pH, which lowered the surface coverage of the water droplets by modified BC. When the pH was re-adjusted to 1 again, w/o emulsions re-formed for C₆– and C₁₂–BC stabilised emulsions. C₂–BC stabilised emulsions, on the other hand, underwent an irreversible pH-triggered transitional phase separation and inversion. This difference in phase behaviour between C₂–BC and C₆–/C₁₂–BC was attributed to the hydrolysis of the ester bonds of C₂–BC at high pH. This hypothesis is in good agreement with the measured degree of surface substitution (DSS) of modified BC after the pH-triggered experiments. The DSS of C₂–BC decreased by 20% whilst the DSS remained constant for C₆– and C₁₂–BC.     

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。     

The effect of hydrodynamic parameters on the production of Pickering emulsions in a baffled stirred tank

Pickering emulsions are potential industrial scale alternatives to surfactant-based emulsions. The stability of Pickering emulsions depends on the physicochemical nature of the liquid–particle interface and the hydrodynamic conditions of the production process. This article investigates the effect of hydrodynamic conditions on the drop size of concentrated Pickering emulsions in baffled stirred tanks. Oil in water emulsions composed of silicon oil, water, and hydrophilic glass beads as stabilizing particles were produced. Two impellers were used at different sizes: Rushton turbine (RT) and pitched blade turbine. The effects of power per mass, Reynolds number, tip speed, and Weber number on the droplet sizes were studied. The energy dissipated around the impeller and the size of the impeller high shear zone were found to be critical to the emulsion droplet sizes. The breakup and droplet-particle contact mechanism of the RT was found to be more favorable for the production of the Pickering emulsions.     

纳米二氧化硅的疏水改性及其对Pickering乳液的稳定作用

为了探究固体粒子对乳液的稳定作用,采用L-赖氨酸作为催化剂合成纳米SiO2粒子,并用六甲基二硅胺烷(HMDS)对纳米SiO2粒子进行表面疏水改性,将经过HMDS改性后的纳米SiO2粒子作为稳定剂制备出Pickering乳液。通过粒径分析仪、场发射透射电子显微镜、FTIR、TG-DSC、接触角测量仪、光学显微镜、电导率仪分别对纳米SiO2的制备、表面改性和Pickering乳液的性能进行了表征。结果表明,成功合成出粒径小且形貌均一的硅球,具有疏水性的三甲基硅基成功接枝到纳米SiO2的表面;不同纳米SiO2浓度制备的Pickering乳液,发现随着SiO2浓度的增大,乳液的稳定性逐渐增强,乳液液滴直径呈现减小的趋势;不同油水比制备的Pickering乳液,发现随着油相体积的增大,乳液的稳定性呈现增大的趋势。     

Effect of dispersed phase feed time on the droplet size of Pickering emulsions produced in a stirred tank

The aim of this study was to investigate the effect of feed time of the oil phase on the average droplet size of Pickering emulsions produced in stirred tanks. Three types of impellers were tested: RT, up-pumping PBT (PBTU), and down-pumping PBT (PBTD). All the impellers were tested at two sizes, T/3 and T/2. All configurations were compared at constant tip speed, power per mass, and impeller Reynolds number. The droplet diameters were measured in Mastersizer® 3,000 (Malvern). The results showed that an increase in feed time causes a reduction in the average droplet size. At lower impeller speeds and higher feed times, the effect is more pronounced. It was found that some other geometric parameters also have an impact on the average droplet size.     

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。     

Temperature‐responsive polymers with LCST in the physiological range and their applications in textiles

Current academic and industrial research sustains large efforts to synthesize and develop environmentally responsive smart materials. The temperature‐responsive materials with a trigger temperature in the physiological range attract much attention due to their potential biomedical applications. We describe their chemistry and the way to synthesize them, focusing on applications for smart clothing fabrication. Copyright © 2007 Society of Chemical Industry     

Pickering乳状液及其在油田中的应用

随着纳米技术的不断进步,Pickering乳状液由于其独特的优势,在食品、化妆品、医药等领域有着广泛的应用。目前,Pickering乳状液在石油领域的应用国外已经较为成熟,而国内只有少数论文提及。因此,从Pickering乳状液形成与稳定的机理的分析入手,讨论了Pickering乳状液的稳定性影响因素及其流变学特性,最后介绍了Pickering乳状液在油田领域的应用现状及前景。结论认为:(1)Pickering乳状液由于其独特的稳定性,针对它的破乳技术将是一个重要的研究方向。(2)对环境刺激响应的固体颗粒乳化剂的深入研究将会更好地促进Pickering乳状液在油田领域的应用。(3)为促进Pickering乳状液在油田领域的广泛应用,可重点考虑对纳米SiO2和纳米CaCO3的改性。     

Toward efficient water/oil separation material: Effect of copolymer composition on pH‐responsive wettability and separation performance

Interest in functional soft matter with stimuli‐responsive wettability has increasingly intensified in recent years. From the chemical product engineering viewpoint, this study aims to fabricate reversible pH‐responsive polymeric surfaces with controllable wettability using [poly(2,2,3,4,4,4‐hexafluorobutyl methacrylate)‐block‐ poly(acrylic acid) (PHFBMA‐b‐PAA)] block copolymers. To attain this aim, three block copolymers with different PAA segment lengths were synthesized for the first time through Cu(0)‐mediated reversible‐deactivation radical polymerization and hydrolysis reaction. pH‐induced controllable wettability was achieved by spin‐coating the resulting block copolymers onto silicon wafers. Results showed that the pH‐responsive wetting behavior was introduced by incorporating the PAA block, and that the responsiveness of as‐fabricated surfaces was greatly influenced by PAA content. All three evolutions of water contact angle with pH shared a similar inflection point at pH 5.25. Furthermore, on the basis of the wetting properties and mechanism understanding, the application of copolymer coated meshes in layered water/oil separation was exploited. Given their superhydrophilicity and underwater superoleophobicity, PHFBMA₇₀‐b‐PAA₁₄₈ and PHFBMA₇₀‐b‐PAA₂₁₁ coated stainless steel meshes (SSMs) can efficiently separate water from different mixtures of organic solvent and water with high flux. However, considering long‐term use, the PHFBMA₇₀‐b‐PAA₁₄₈ coated SSM with good stability may be the best copolymer for water/oil separation. Therefore, a coordination of structure, composition, and functionality was necessary to enable practical applications of the functional materials. © 2016 American Institute of Chemical Engineers AIChE J, 62: 1758–1771, 2016