摘要
与传统乳液相比,高内相乳液具有较高的内相体积分数,分散相液滴之间相互挤压使其产生形变,形成了被连续相液膜分隔的无规则多面体,从而赋予高内相乳液黏度高、界面膜面积大等特点.以高内相乳液为模板,制备多孔功能材料时,高内相乳液内部液滴特殊的多面体结构赋予多孔材料高比表面积、高孔隙率以及轻质量等优点.而且,相比于其他传统方法如微乳液法、化学腐蚀法、相分离法等,可通过调节高内相乳液的内外相体积分数、稳定剂种类等因素,实现精准调控材料孔隙分布、孔容量以及孔密度的目的,因而在气体吸附、药物递送、污染物过滤等方面展现出广阔的应用前景.本文主要介绍了近年来发展出的多种高内相乳液的种类及其相应的制备方法,详细讨论了稳定剂的选择以及多种外界环境因素对高内相乳液稳定性的影响,并展望了该类材料的研究前景和潜在应用,即利用高内相乳液制备多孔功能材料,并论述了现阶段多孔功能材料在实际应用中的优点以及局限性,为后期的实际应用提供了有效的解决方案.
High internal phase emulsions(HIPEs)are usually defined as a kind of superconcentrated emulsions,in which the minimum internal phase volume fraction reaches to 0.74.Comparing with traditional emulsions,high internal phase emulsions(HIPEs)tend to be highly viscous,solid-like emulsions because of their higher internal phase volume fraction.Thus,focusing on their microstructure,the shape of the oil droplets turned from spheres to irregular polyhedrons separated by a continuous phase film,leading to the deformation of the inner phase droplets.Obviously,the selection of suitable and effective stabilizers based on different stabilization mechanisms is vital for the emulsification process.Up to now,mainly three types of stabilizers based on dissimilar stabilization mechanisms have been successfully developed,including traditional surfactants,solid particles,and low molecular weight or macromolecular gelators.Given that the unique structural features,the wide applicability of HIPEs in pharmaceutical formulations,controlled-release deliverers,cosmetics industries,cold chain logistics and fatty food products has received considerable attentions.Moreover,owing to the characteristics of high viscosity and large interface film area,it is feasible to use high internal phase emulsion as a template to prepare porous functional materials,and the polyhedral structure of the internal droplets endows the final obtained porous material with higher specific surface area,higher porosity and lighter weight.Comparing with the other traditional methods,such as microemulsion method,chemical corrosion method,phase separation method,and so on,the parameters of porous material,including pore distribution,pore capacity and pore density can be easily and precisely controlled by altering the internal and external phase volume fraction,the type of stabilizer and other factors.Overall,the porous materials based on HIPEs template possess many advantages,including low cost,high capacity and excellent reversibility showing huge potential in gas adsorption,separation and enrichment,drug delivery and other practical fields.The present review provides the advanced progresses of preparation of HIPEs and applications in functional materials,with sophisticated porous structures and desirable environmental adaptabilities.Initially,we clearly summarize the synthesizing strategies in regard to both corresponding mechanisms and typical examples developed in recent years,including oil-inwater(O/W)HIPEs,water-in-oil(W/O)HIPEs,oil-in-oil(O/O)HIPEs,high internal phase supercritical fluid emulsions,high internal phase ionic liquid emulsion and high internal phase deep eutectic solvent emulsion.Subsequently,we also clearly discuss in detail the selection of stabilizers including traditional surfactants,solid particles,and low molecular weight or macromolecular gelators,and the influence of various external environmental factors on the stability of high internal phase emulsions(the features of phase,temperature and electrolyte).Meanwhile,we further look forward to their potential applications in functional material preparation,including the functional porous materials,flexible wearable devices and stimulus responsive material.Moreover,the limitations of the existing porous functional materials based on high internal phase emulsion are discussed,including inadequately mechanical performance and unsatisfactory biocompatibility,which will provide significant guidance for synthesizing strategies and practical application in the future.In the end,the current challenges and perspectives on the future development of functional HIPEs materials are also discussed.
作者
李可扬
张卓
董姝丽
Keyang Li;Zhuo Zhang;Shuli Dong(Key Laboratory of Colloid and Interface Chemistry,Ministry of Education,Shandong University,Jinan 250100,China;School of Chemistry and Chemical Engineering,Ocean University of China,Qingdao 266100,China)
出处
《科学通报》
EI
CAS
CSCD
北大核心
2021年第14期1703-1716,共14页
Chinese Science Bulletin
基金
国家自然科学基金(21420102006,21773144)资助。
关键词
高内相乳液
稳定剂
乳液模板法
多孔材料
响应材料
high internal phase emulsion
stabilizer
emulsion template method
porous materials
responsive materials
