Participating Group (2020-2021)

High-Speed AFM Visualization of Structural Dynamics of Porous Coordination Polymers Induced External Stimuli

Research Outline

Porous Coordination Polymer (PCP), which is expected to have many industrial applications, possess the typical characteristics of soft crystals because its crystal structure flexibly changes in response to external stimuli such as guest molecule adsorption, pressure, and electric field. Changes in the crystal structure in response to external stimuli are brought by local changes in intramolecular structure and triggered global changes in the crystal. Understanding the local structural and physical changes, and their propagation dynamics at the crystal surface should be quite important for the functional design and performance improvement of porous crystals. In this study, the nanoscale dynamics of PCP surfaces in response to external stimuli are directly visualized by high-speed atomic force microscopy (AFM). The research subjects are visualizations of I): adsorption of guest molecules onto porous crystals such as MMFs and MOFs and surface propagation of lattice distortion, II): growth process of gold nanoparticles on MMF surface, and III) lattice distortion induction and selective control of guest molecule adsorption by local mechanical stimuli. These studies will enable us to gain fundamental knowledge for functional design and performance improvement of PCPs.

Participating Group (2018-2019)

Development of Evaluation Techniques for Structure and Physical Properties and Dynamics of Soft Crystals Based on High-Speed Atomic Force Microscopy

Research Outline

Soft crystals change their optical and mechanical properties in response to the external environment and weak mechanical stimuli. Changes in the physical properties in response to the stimuli are resulted from changes in the molecular structure and the associated assembled structure. Microscopy techniques which enable probing dynamics of structure and physical properties on the crystal surface with high spatiotemporal resolution should provide deep insight into function expression mechanisms of soft crystals. This researcher has been developing high-speed atomic force microscopy (HS-AFM) and succeeded in visualizing the structural dynamics of biomolecules at work. Recently, the application of HS-AFM is extended to visualizing artificial molecular systems and therefore should be a powerful tool for evaluating dynamic properties of soft crystals. The aim of this research is to establish techniques to visualize the dynamics of the structure and physical properties on soft crystals in response to external stimulus such as photo irradiation and mechanical force based on HS-AFM technique, and to reveal nanoscale mechanisms of the emergent functions of soft crystals.