Water-ion permselectivity of narrow-diameter carbon nanotubes
Yu‐Hao Li, Zhongwu Li, Fikret Aydin, Jana Quan, Xi Chen, Yun‐Chiao Yao, Cheng Zhan, Yunfei Chen, Tuan Anh Pham, Aleksandr Noy
Abstract
Carbon nanotube (CNT) pores, which mimic the structure of the aquaporin channels, support extremely high water transport rates that make them strong candidates for building artificial water channels and high-performance membranes. Here, we measure water and ion permeation through 0.8-nm-diameter CNT porins (CNTPs)-short CNT segments embedded in lipid membranes-under optimized experimental conditions. Measured activation energy of water transport through the CNTPs agrees with the barrier values typical for single-file water transport. Well-tempered metadynamics simulations of water transport in CNTPs also report similar activation energy values and provide molecular-scale details of the mechanism for water entry into these channels. CNTPs strongly reject chloride ions and show water-salt permselectivity values comparable to those of commercial desalination membranes.