Possibility of Novel Crystallization by Controlling Size Distribution with Multiple Degrees of Freedom

2022 Fiscal Year Final Research Report

• Project/Area Number: 18K03500
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 13020:Semiconductors, optical properties of condensed matter and atomic physics-related
• Research Institution: Aichi Institute of Technology
• Principal Investigator: Uwaha Makio 愛知工業大学, 基礎教育センター, 客員教授 (30183213)
• Co-Investigator(Kenkyū-buntansha): 勝野 弘康 北海道大学, 低温科学研究所, 博士研究員 (70377927)
• Project Period (FY): 2018-04-01 – 2023-03-31
• Keywords: 結晶のカイラリティ転換 / ヴィエドゥマ熟成 / 温度循環 / 結晶多型 / 結晶サイズ分布 / 準安定状態

Outline of Final Research Achievements

Certain molecules have a left-right type and can be easily converted between the left and right types in solution, and molecules of both types form crystals separately. Some molecules that do not have a left-right distinction also have left-right crystal structures, such as quartz crystals. When the microcrystalline powder in solution is continuously crushed and agitated, or the solution temperature is repeatedly raised and lowered, all of the microcrystals that were of equal amounts on both sides become one or the other type. We have explained this amazing phenomenon by focusing on the contribution of molecular clusters to crystal growth and studying the size distribution of the clusters. We also showed theoretically that this mechanism can be applied to convert stable crystals into energetically unfavorable metastable crystals, a phenomenon that at first glance seems to violate the laws of nature.

Free Research Field

結晶成長理論

Academic Significance and Societal Importance of the Research Achievements

この研究で提案したカイラルクラスターの結晶化による結晶や分子のカイラリティ転換モデルは，結晶粉砕や温度循環の方法によるほとんどの実験結果と整合する最有力なモデルと言える．詳細な解析で温度循環法の中心となる過程が，高温期に溶液中のクラスターによって多数派相の溶解が抑えられることにあることを示した．これらの方法は，適切な条件がそろえばエネルギー的に不利な準安定多型結晶を安定結晶から簡単に作り出すことを可能としうる．この研究は異常現象の機構解明にとどまらず，工学的にも重要なものになりうる．