Re-examining the origins of electric double layer interactions

2020 Fiscal Year Final Research Report

• Project/Area Number: 18K03555
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 13040:Biophysics, chemical physics and soft matter physics-related
• Research Institution: University of Tsukuba
• Principal Investigator: Hishida Mafumi 筑波大学, 数理物質系, 助教 (70519058)
• Co-Investigator(Kenkyū-buntansha): 秋山 良 九州大学, 理学研究院, 准教授 (60363347)
• Project Period (FY): 2018-04-01 – 2021-03-31
• Keywords: コロイド間相互作用 / 電気二重層斥力 / Donnan平衡 / DLVO理論

Outline of Final Research Achievements

In the past study, we have found that the interaction between charged phospholipid membranes does not follow the DLVO theory. In this study, to understand the mechanism of the electric double layer interaction in colloidal aggregation systems with a systematic manner, the dependence of the inter-colloidal distances of spherical colloids on the ionic species and the colloidal concentration were investigated using precise measurement of small angle X-ray scattering. Since the results still did not follow the DLVO theory, we developed a new theory that integrates the Donnan equilibrium model and the DLVO theory.

Free Research Field

ソフトマター物理学、コロイド科学

Academic Significance and Societal Importance of the Research Achievements

洗剤や塗料など、多くの工業製品はコロイドで作られており、その分散性の理解は学術的にも応用的にも大変重要である。本研究では、コロイドの分散・凝集の物理的なメカニズムがこれまで100年近く信じられてきたものとは異なる機構で進むことを見出した。精密な実験と新しい理論の構築を両輪で進めた。水中で荷電性のコロイド間に働く力の起源を根本から問い直すことに成功し、過去の理論の問題点と、より妥当な考え方を示すことができた。