Mesoscale simulation analysis of particle structure formation during drying

2018 Fiscal Year Final Research Report

• Project/Area Number: 17K14849
• Research Category: Grant-in-Aid for Young Scientists (B)
• Allocation Type: Multi-year Fund
• Research Field: Properties in chemical engineering process/Transfer operation/Unit operation
• Research Institution: The University of Tokyo
• Principal Investigator: Tatsumi Rei 東京大学, 環境安全研究センター, 特任助教 (00749202)
• Project Period (FY): 2017-04-01 – 2019-03-31
• Keywords: コロイド / 乾燥 / 粒子膜 / 偏析 / 数値シミュレーション

Outline of Final Research Achievements

We investigated the structure formation of particles in drying colloidal suspensions through mesoscale simulations that compute the Brownian motion of colloidal particles. The structure formation of the particles during drying is governed by the competition between the Brownian motion of the particles and the recession of the free surface according to liquid evaporation. The drying rate falls with a decrease in the liquid permeability of the growing concentrated layers. We found that the aggregation of the particles results in an increase in the porosity of the concentrated layers and suppresses the falling of the drying rate.
The mesoscale simulations also reproduced the segregation of small particles to the surface in drying bimodal suspensions. We found that the segregation is enhanced with an increase in the particle size ratio and that there is a drying rate at which the segregation is the most enhanced.

Free Research Field

化学工学

Academic Significance and Societal Importance of the Research Achievements

微粒子分散液の乾燥において，粒子系構造の形成が誘起される自己組織化現象が起こる．この現象を積極的に利用して，微細構造を有する機能材料の作製が行われている．本研究は，微粒子分散液の性状（粒子の分散・凝集）および乾燥の操作条件（乾燥速度）と粒子系構造の関係を明らかにすることで，構造制御による材料高性能化のための材料作製条件設計に対して知見を与えるものである．