Establishment of evaluation method for detergency of surfactants based on the latest solution statistical thermodynamic theory

2021 Fiscal Year Final Research Report

• Project/Area Number: 18K13030
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 08030:Family and consumer sciences, and culture and living-related
• Research Institution: National Institute of Advanced Industrial Science and Technology (2021); Hiroshima University (2019-2020); Japan Agency for Marine-Earth Science and Technology (2018)
• Principal Investigator: Kanasaki Yu 国立研究開発法人産業技術総合研究所, 材料・化学領域, 産総研特別研究員 (90804667)
• Project Period (FY): 2018-04-01 – 2022-03-31
• Keywords: 洗浄 / 溶液熱力学 / 可溶化 / 相互作用 / 染料 / 水晶振動子

Outline of Final Research Achievements

Cleaning power is determined by the interactions between contaminants, detergent, and water. However, it is difficult to quantify the interactions because they changes from moment to moment during practical cleaning. In order to understand the relationship between the structure of the detergent and the cleaning power from the interactions, it is necessary to coarse-grain the elementary processes of cleaning, which have become complicated, and to understand the effect of the change in the interactions between contaminants, detergent, and water before and after cleaning on the cleaning power. In this study, we quantified the interaction change for the solubilization of dirt from aggregates by Kirkwood-Buff integration and investigated the effect of the interaction change on the cleaning power. For the quantification of stains, we developed a new detergency evaluation device and evaluation method that can quantify very small amounts of contaminants using a quartz crystal microbalance.

Free Research Field

界面科学、被服管理学

Academic Significance and Societal Importance of the Research Achievements

これまで、界面活性剤の構造と油や水との親和性、さらに溶液物性との関係を明らかにするための研究が数多く行われてきた。油や水との親和性をはかる指標には、親水―疎水バランス(HLB)があり、界面活性剤の親水基と疎水基の割合により、乳化剤や起泡剤、洗浄剤といった用途を決定する指標となっている。しかしながら、洗浄剤として用いられる界面活性剤の中で、どのような構造が洗浄に効果的であるのかを理解するための手法がない。本研究ではKirkwood-Buff積分を用いて相互作用変化から洗浄力を評価し、新たな洗浄剤を評価指標としての可能性を示した。