Interaction Force Landscapes within and Surrounding Hydrophobic Nanopockets Revealed by Three-Dimensional Scanning Atomic Force Microscopy

作者：Moe Ogasawara, Saki Tanaka, Kayo Komatsu, Naoki Kishimoto, Dapeng Zhang, Tomoki Yoneda, Yasuhide Inokuma, Masayuki Morimoto, Akio Ohta, Hitoshi Asakawa · 发表于：The Journal of Physical Chemistry C · 年份：2025 · DOI：10.1021/acs.jpcc.5c06181 · 研究领域：Surface Chemistry and Catalysis、Force Microscopy Techniques and Applications、Supramolecular Self-Assembly in Materials

The precise design of 2D supramolecular assemblies constructed from 3D organic molecules on the surfaces of sp 2 carbon materials is expected to advance the development of functional materials and devices. Supramolecular assemblies containing nanopockets can exhibit functions such as molecular recognition; however, directly probing and elucidating the intermolecular interactions and the associated interaction energies on the single-nanopocket scale remain a significant challenge. In this study, subnanometer resolution atomic force microscopy (AFM) was used to reveal that a tetrakis(4-ethynylphenyl)methane derivative, modified with a single oligo(ethylene glycol) chain and used as an organic building block, formed high-density hydrophobic nanopockets in its monolayer through CH−π interactions between the compact ethynyl termini. Furthermore, three-dimensional scanning AFM (3D-AFM) measurements revealed a distinct distribution of attractive forces within the hydrophobic nanopockets, attributed to a decrease in water density arising from confinement effects by nanometer-sized spaces. Importantly, 3D-AFM imaging, which can spatially resolve the distribution of interaction forces with piconewton-level sensitivity, allows the construction of interaction energy landscapes at the single-nanopocket level, which is not possible using established methods. This capability of 3D-AFM imaging is expected to advance the microscopic understanding of molecular recognition mechanisms in host–gu...