Chemical Engineering Department, Loughborough University, Loughborough, Leicestershire LE11 3TU, United Kingdom; Laboratory of Chemical Dynamics, Vinča Institute of Nuclear Sciences, University of Belgrade, P.O. Box 522, 11001 Belgrade, Serbia.
Adv Colloid Interface Sci. 2015 Nov;225:53-87. doi: 10.1016/j.cis.2015.07.013. Epub 2015 Aug 20.
This paper provides an overview of membrane emulsification routes for fabrication of structured microparticles with tailored properties for specific applications. Direct (bottom-up) and premix (top-down) membrane emulsification processes are discussed including operational, formulation and membrane factors that control the droplet size and droplet generation regimes. A special emphasis was put on different methods of controlled shear generation on membrane surface, such as cross flow on the membrane surface, swirl flow, forward and backward flow pulsations in the continuous phase and membrane oscillations and rotations. Droplets produced by membrane emulsification can be used for synthesis of particles with versatile morphology (solid and hollow, matrix and core/shell, spherical and non-spherical, porous and coherent, composite and homogeneous), which can be surface functionalised and coated or loaded with macromolecules, nanoparticles, quantum dots, drugs, phase change materials and high molecular weight gases to achieve controlled/targeted drug release and impart special optical, chemical, electrical, acoustic, thermal and magnetic properties. The template emulsions including metal-in-oil, solid-in-oil-in-water, oil-in-oil, multilayer, and Pickering emulsions can be produced with high encapsulation efficiency of encapsulated materials and narrow size distribution and transformed into structured particles using a variety of solidification processes, such as polymerisation (suspension, mini-emulsion, interfacial and in-situ), ionic gelation, chemical crosslinking, melt solidification, internal phase separation, layer-by-layer electrostatic deposition, particle self-assembly, complex coacervation, spray drying, sol-gel processing, and molecular imprinting. Particles fabricated from droplets produced by membrane emulsification include nanoclusters, colloidosomes, carbon aerogel particles, nanoshells, polymeric (molecularly imprinted, hypercrosslinked, Janus and core/shell) particles, solder metal powders and inorganic particles. Membrane emulsification devices operate under constant temperature due to low shear rates on the membrane surface, which range from (1-10)×10(3) s(-1) in a direct process to (1-10)×10(4) s(-1) in a premix process.
本文概述了用于制造具有特定应用所需特性的结构化微颗粒的膜乳化方法。讨论了直接（自下而上）和预混（自上而下）膜乳化工艺，包括控制液滴尺寸和液滴生成区的操作、配方和膜因素。特别强调了在膜表面上产生受控剪切的不同方法，例如膜表面的横流、旋流、连续相中的前后流动脉动以及膜的振动和旋转。通过膜乳化产生的液滴可用于合成具有多种形态（实心和空心、基体和核/壳、球形和非球形、多孔和连续、复合和均匀）的颗粒，这些颗粒可以进行表面功能化和涂层，或者负载大分子、纳米颗粒、量子点、药物、相变材料和高分子气体，以实现控制/靶向药物释放，并赋予特殊的光学、化学、电学、声学、热学和磁学性能。可以使用高封装效率的封装材料和窄的粒径分布来制备模板乳液，包括油包水、油包油包水、多层和 Pickering 乳液，并使用各种固化工艺将其转化为结构化颗粒，例如聚合（悬浮、微乳液、界面和原位）、离子凝胶化、化学交联、熔融固化、内部分相分离、层层静电沉积、颗粒自组装、复杂凝聚、喷雾干燥、溶胶-凝胶处理和分子印迹。通过膜乳化产生的液滴制备的颗粒包括纳米团簇、胶体囊泡、碳气凝胶颗粒、纳米壳、聚合物（分子印迹、超交联、Janus 和核/壳）颗粒、焊料金属粉末和无机颗粒。由于膜表面的剪切速率低，在（1-10）×10(3) s(-1)范围内，直接过程为（1-10）×10(4) s(-1)范围内，预混过程中，膜乳化装置在恒温下运行。
