Non-Destructive Quantitative Analysis of Interfacial Nanostructures in Organic Transistors and Water Purification Membranes Using Neutron Reflectivity

We will introduce recent advances in utilizing Neutron Reflectivity (NR) for the non-destructive, quantitative elucidation of the internal nanostructures of complex polymer thin films used in high-performance organic transistors and high-efficiency water purification membranes. First, in a soluble acene/polymer blend system, a deuterated polymer was directly employed as a matrix to maximize the contrast in neutron scattering length density (SLD) between components. Through this approach, the exact location, thickness, and nanometer-scale roughness of the charge transport interface—which serves as the actual conduction channel within the vertically phase-separated blend film—were successfully isolated and determined quantitatively via depth profiling. Furthermore, the effects of the subtle behavioral differences in the deuterated polymer on enhancing the thermal and electrical stability, as well as the charge mobility of the devices, are discussed. This advanced interfacial resolution technique was further extended to analyze water-purification polyamide thin films synthesized spontaneously at the liquid–gas interface. NR precisely tracked the distribution and density variations of the non-uniform nanochannel networks inside the membrane, which are otherwise physically inaccessible, with a few-nanometer resolution. Consequently, this presentation aims to share how the neutron reflectivity technique serves as a pivotal tool for establishing clear structure-property relationships across diverse polymer-based applications, ranging from controlling the charge transport interface in next-generation intelligent devices to optimizing the permeation architecture of eco-friendly separation membranes.