Reika Katsumata

Research Interests

Design Extremely Confined Soft/Hard Interfaces

Current Research

Katsumata Group’s research goal is to establish design rules of extremely confined soft/hard interfaces. Extremely confined interfaces become more critical for hybrid materials design at the intersection of two emerging research thrusts: precise synthesis of sequence-defined polymers and miniaturization of things. Examples in which such interfaces are prevalent include nanocomposites with ultra-small nanoparticles, ultra-thin polymer films/coatings, and two-dimensional (2D) materials with critical dimensions smaller than 10 nm. Despite emerging capabilities to synthesize these materials with precision, the influence of extreme confinement is not fully understood. The thermophysical properties of extremely confined molecules are often governed by rules different from those of bulk and moderately confined systems (> 10 nm scale). As the nanoparticle diameter and the coating thickness approach the size of polymer segments, molecular-level understanding becomes critical. In particular, my group focuses on three areas: dynamics, mechanics, and wettability. Polymer dynamics is the foundation of my research program and involves elucidating molecular movements due to perturbations by neighboring molecules, introducing molecular-level heterogeneity. The heterogeneous polymer dynamics then dictates the tangible properties we can touch and feel: wettability and mechanics. Wettability is an incarnation of polymer dynamics, as molecules rearrange their configurations at interfaces. Analogously, mechanical properties are macroscopic responses of polymer dynamics on different length and time scales. Our approaches include fluorescence spectroscopy, rapid thermal annealing, and film-stress measurement in addition to conventional instrumentation and synthesis methods for polymer science and engineering.