Investigation of self-propelled droplets in various chemical gradient

2014 Fiscal Year Final Research Report

• Project/Area Number: 24656469
• Research Category: Grant-in-Aid for Challenging Exploratory Research
• Allocation Type: Multi-year Fund
• Research Field: Properties in chemical engineering process/Transfer operation/Unit operation
• Research Institution: Osaka University
• Principal Investigator: OKANO Yasunroi 大阪大学, 基礎工学研究科, 教授 (90204007)
• Co-Investigator(Kenkyū-buntansha): BAN Takahiko 大阪大学, 大学院基礎工学研究科, 講師 (60454485) ; TAKAGI Youhei 大阪大学, 大学院基礎工学研究科, 助教 (40435772)
• Project Period (FY): 2012-04-01 – 2015-03-31
• Keywords: マランゴニ効果 / Kortweg効果 / ソフトマター / 自己組織化 / 環境応答性機能

Outline of Final Research Achievements

We have developed self-propelled droplets having the abilities to detect a chemical gradient, to move toward a higher concentration of a specific metal ion (particularly the dysprosium ion), and to extract it. Such abilities rely on the high surface activity of 2-ethylhexyl phosphoric acid (DEHPA) in response to pH and the affinity of DEHPA for the dysprosium ion. The oil droplets loaded with DEHPA spontaneously move around beyond the threshold of pH even in a homogeneous pH field. In the presence of a gel block containing metal ions, the droplets show directional sensing and their motility is biased toward higher concentrations. The metal ions investigated can be arranged in decreasing order of directional sensing as Dy3+ ≫ Nd3+ > Y3+ > Gd3+. Furthermore, the analysis of components by using an atomic absorption spectrophotometer reveals that the metal ions can be extracted from the environmental media to the interiors of the droplets.

Free Research Field

化学工学