物理化学学报 >> 2020, Vol. 36 >> Issue (10): 1910005.doi: 10.3866/PKU.WHXB201910005

所属专题: 胶体与界面化学前沿

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胶体颗粒稳定的界面及胶体颗粒在界面的相互作用

孙冠卿1, 易宗霖2, 魏涛1,2,*()   

  1. 1 合成与生物胶体教育部重点实验室,江南大学,江苏 无锡 214122
    2 香港中文大学化学系,香港特别行政区新界沙田
  • 收稿日期:2019-10-07 录用日期:2019-12-31 发布日期:2020-02-03
  • 通讯作者: 魏涛 E-mail:tongai@cuhk.edu.hk
  • 作者简介:To NGAI now is Professor in the Department of Chemistry, Assistant Dean (Research) of Science at the Chinese University of Hong Kong (CUHK), and Fellow of the Royal Society of Chemistry (FRSC). He received his B.Sc. in chemistry at CUHK in 1999. In 2003, he obtained the Ph.D at the same university, where he worked on light scattering and polymer interaction in solution. He moved to BASF (Ludwigshafen, Germany) in 2003 as the postdoctoral fellow for two years, working on colloids and surface chemistry. After a short postdoctoral training in the Chemistry Department at the University of Minnesota in 2005, he joined the Chemistry Department at CUHK in 2006 as a research assistant professor. He has been appointed as an assistant professor in 2008, and early promoted to associate professor in 2012. In 2017, he was promoted to Professor. His current research interests center around the colloids, surface chemistry, polymers and soft matter
  • 基金资助:
    国家自然科学基金(21703085);国家自然科学基金(21972057);中央高校基本科研业务费专项资金(JUS 1042050205182110)

Particle-Stabilized Interfaces and Their Interactions at Interfaces

Guanqing Sun1, Zonglin Yi2, To Ngai1,2,*()   

  1. 1 The Key Laboratory of Synthetic and Biological Colloids, Ministry of Education, Jiangnan University, Wuxi 214122, Jiangsu Province, P. R. China
    2 Department of Chemistry, The Chinese University of Hong Kong, Shatin, NT, Hong Kong SAR, P. R. China
  • Received:2019-10-07 Accepted:2019-12-31 Published:2020-02-03
  • Contact: To Ngai E-mail:tongai@cuhk.edu.hk
  • Supported by:
    the National Natural Science Foundation of China(21703085);the National Natural Science Foundation of China(21972057);the Fundamental Research Funds for the Central Universities of China(JUS 1042050205182110)

摘要:

胶体颗粒稳定的分散体系如乳液、泡沫和气泡等体系在众多研究领域吸引了越来越多的关注。胶体颗粒的吸附机理、油-水界面和气-水界面的胶体颗粒稳定机制以及吸附于界面的胶体颗粒乳液相互作用对这些分散体系的实际应用至关重要。虽然在相关方面已经有众多研究,胶体颗粒对界面的稳定作用和胶体颗粒之间的相互作用仍然存在很多问题,值得进一步研究。在本文中,我们首先系统地回顾了历来胶体颗粒稳定的乳液和气泡体系的研究,并概括地介绍了在该领域内较为重要和较为成熟的研究进展,包括乳液、泡沫和液体弹珠等。人们早已认识到胶体颗粒在界面的吸附现象,在学术上的探讨也已经超过一个世纪。上世纪八十年代有研究者提出了定量的理论模型来描述这种现象。该理论从自由能降低的角度解释了为何胶体颗粒会吸附到界面上,并且能将胶体颗粒对两相的浸润性与乳液和泡沫体系的稳定性联系起来。在乳液稳定性方面,有大量的研究支撑了上述理论;研究者们制备了具有响应性的乳液体系,如pH/温度响应性。之后,我们讨论了吸附在界面的胶体颗粒的相互作用的最新进展,并提出了该领域内尚未解决的问题。由于需要精密的仪器和熟练的操作技巧,胶体颗粒在界面的相互作用实验和理论研究之间还存在巨大的差距。虽然弯曲界面更为常见,实验上通常采用水平界面作为模型界面来研究胶体颗粒在界面的相互作用。胶体颗粒在界面的引入会由摩擦导致电荷存在,这很可能是长程静电相互作用的原因。最后,我们介绍了胶体颗粒稳定的分散体系的在包埋、食品、控释和干水的制备等领域的应用。使用乳液液滴作为平台,是制备包埋体系的主要手段之一。吸附在界面的胶体颗粒,不仅可以稳定界面,也可以作为胶体微胶囊的壁材。使用自然来源的胶体颗粒为稳定颗粒,乳液体系可方便地应用于食品相关领域。近年来由于其全部由水相构成,水-水体系吸引了越来越多的关注。气-水界面与油-水界面具有相同的稳定机制,我们对一些基于气-水界面的应用进行了探讨。我们希望借由该篇文章鼓励更多的研究人员参与到胶体颗粒稳定界面的研究中来,并基于此开发出越来越多的新颖应用。

关键词: 界面, 粒子吸附, 皮克林乳液, 粒子-粒子相互作用, 干水, 微胶囊

Abstract:

Particle-stabilized dispersions such as emulsions, foams and bubbles are catching increasing attentions across a number of research areas. The adsorption mechanism and role of these colloidal particles in stabilizing the oil-water or gas-water interfaces and how these particles interact at interfaces are vital to the practical use of these dispersion systems. Although there have been intensive investigations, problems associated with the stabilization mechanisms and particle-particle interactions at interfaces still remain to explore. In this paper, we first systematically review the historical understanding of particle-stabilized emulsions or bubbles and then give an overview of the most important and well-established progress in the understanding of particle-stabilized systems, including emulsions, foams and liquid marbles. The particle-adsorption phenomena have long been realized and been discussed in academic paper for more than one century and a quantitative model was proposed in the early 1980s. The theory can successfully explain the adsorption of solid particles onto interface from energy reduction approaches. The stability of emulsions and foams can be readily correlated to the wettability of the particles towards the two phases. And extensive researches on emulsion stability and various strategies have been developed to prepared dispersion systems with a certain trigger such as pH and temperature. After that, we discuss recent development of the interactions between particles when they are trapped at the interface and highlight open questions in this field. There exists a huge gap between theoretical approaches and experimental results on the interactions of particles adsorbed at interfaces due to demanding experimental devices and skills. In practice, it is customary to use flat surfaces/interfaces as model surfaces to investigate the particle-particle at interfaces although most of the time interfaces are produced with a certain curvature. It is shown that the introduction of particles onto interfaces can generate charges at the interfaces which could possibly account for the long range electrostatic interactions. Finally, we illustrate that particle-stabilized dispersions have been found wide applications in many fields and applications such as microcapsules, food, biomedical carriers, and dry water. One of the most investigated areas is the microencapsulation of actives based on Pickering emulsion templates. The particles adsorbed at the interface can serve as interfacial stabilizers as well as constituting components of shells of colloidal microcapsules. Emulsions stabilized by solid particles derived from natural and bio-related sources are promising platforms to be applied in food related industries. Emulsion systems stabilized by solid particles of the w/w (water-in-water) feature are discussed. This special type of emulsion is attracting increasing attentions due to their all water features. Besides of oil-water interface, particle stabilized air-water interface share similar stabilization mechanism and several applications reported in the literature are subsequently discussed. We hope that this paper can encourage more scientists to engage in the studies of particle-stabilized interfaces and more novel applications can be proposed based on this mechanism

Key words: Interface, Particle adsorption, Pickering emulsions, Particle-particle interaction, Dry waters, Microcapsules

MSC2000: 

  • O647