TECHNICAL NOTE: WATER VAPOR TRANSMISSION RATE AND PERMEANCE OF CELLULOSE NANOCRYSTALS/POLYDIMETHYLSILOXANE HYBRID MEMBRANES MEASURED BY DYNAMIC VAPOR SORPTION

This article describes a fast and reliable method of screening membrane materials designed by measuring moisture vapor transmission rate (WVTR) and permeance of membrane materials using a Payne-style diffusion cell (dry cup) placed in a Dynamic Vapor Sorption (DVS) instrument. The materials were cellulose nanocrystals (CNC)/polydimethylsiloxane (PDMS) hybrid membranes. A casting method was used to fabricate three types of membrane samples. The WVTR and permeance of the samples were measured at two RH (RH) levels of 60% and 80% at 25 degrees C. 'The results revealed that the WVIR and permeance of PDMS membrane samples were increased by 34.33% to 39.69% after adding 1 wt% of CNC in the PDMS matrix. WVTR of all samples increased as RH increased from 60% to 80%, but the permeance decreased with increasing RH. The results of all three types of samples showed good consistency in terms of data discrepancy and the trends of WVTR and permeance with RH. Due to the small sample size, the tests could be completed in a few hours at elevated RHs in comparison with the commonly used Mason jar method according to American Society for Testing and Materials (ASTM) E96/E96M-16. Therefore, the Payne cell method in DVS can provide a fast screening of membrane materials.