Nanosized Water Channels Associated with Hydrophobic and Hydrophilic Fibrillar Arrangements Formed on Nafion Surfaces in Confined Regions

ACS Omega. 2024 May 17;9(22):23567-23572. doi: 10.1021/acsomega.4c00809. eCollection 2024 Jun 4.

Abstract

Herein, the origin of interfacial water nanosized channel distributions attached onto Nafion surfaces is investigated. The surface fibrillary hydrophilic and hydrophobic arrangements were observed on AFM images scanned on Nafion surfaces immersed in water. Then, by analyzing the force vs separation curves, it is possible to map arrays of interfacial water channels and their locations. Nafion surface profiles and the water interfacial patterns are then combined using this AFM technique. As there are no reported experimental techniques to measure water nanochannel cross sections, presented measurements report on their dimensions. Water nanochannels characterized by ε < 7 attached to hydrophilic fibrillary sections form aggregated water domains, a highly organized water structure compared with bulk water. Channels are attached to Nafion surface hydrophilic fibrillary domains in confined sites.