Résumé
The development of membranes for nanofiltration with ionic transport properties that combine ionic permeability and selectivity is essential for improving the performance of water desalination or blue energy generation systems [1]. Besides, lab-on-chips using one or a few nano-channels combining ionic and electronic transport could open up a whole field of fundamental explorations in bio-iono-electronics and its potential applications: single-molecule detection, artificial synapses/neurons, .... etc [2]. Within this general framework, our aim is to study the ion transport properties of a bioinspired artificial nano-channel consisting of a single-walled carbon nanotube (SWCNT) inside which a biological ion channel (BIC) is confined. The first phase of this project consists of verifying whether or not it is possible to confine such a channel in a SWCNT. The BIC being studied is gramicidin. It is a small, well-characterised protein having a helicoidal structure when inserted into the cytoplasmic membrane [3]. Its outer ring is particularly hydrophobic and hence should facilitate its insertion into a SWCNT. The SWCNTs used are purified EC-15 eDIPS whose average diameter, i.e. ~2.1-2.2 nm, is expected to be large enough to accommodate the protein in its helicoidal form. The results presented here show that gramicidin strongly interacts with SWCNTs and gets inserted. This outcome is obtained using a range of technics: XRD, Raman, XPS, TEM and Water Sorption Isotherms. Particular emphasis will be made on the use of Water Sorption Isotherms as a powerful tool for characterising confinement in SWCNT.