TY - JOUR
T1 - Neutron Reflectivity and Performance of Polyamide Nanofilms for Water Desalination
AU - Foglia, Fabrizia
AU - Karan, Santanu
AU - Nania, Manuela
AU - Jiang, Zhiwei
AU - Porter, Alexandra E.
AU - Barker, Robert
AU - Livingston, Andrew G.
AU - Cabral, João T.
N1 - The authors acknowledge BP International Centre for Advanced Materials (BP-ICAM) for financial support
PY - 2017/10/5
Y1 - 2017/10/5
N2 - The structure and hydration of polyamide (PA) membranes are investigated with a combination of neutron and X-ray reflectivity, and their performance is benchmarked in reverse osmosis water desalination. PA membranes are synthesized by the interfacial polymerization of m-phenylenediamine (MPD) and trimesoyl chloride (TMC), varying systematically reaction time, concentration, and stoichiometry, to yield large-area exceptionally planar films of ≈10 nm thickness. Reflectivity is employed to precisely determine membrane thickness and roughness, as well as the (TMC/MPD) concentration profile, and response to hydration in the vapor phase. PA film thickness is found to increase linearly with reaction time, albeit with a nonzero intercept, and the composition cross-sectional profile is found to be uniform, at the conditions investigated. Vapor hydration with H2O and D2O from 0 to 100% relative humidity results in considerable swelling (up to 20%), but also yields uniform cross-sectional profiles. The resulting film thickness is found to be predominantly set by the MPD concentration, while TMC regulates water uptake. A favorable correlation is found between higher swelling and water uptake with permeance. The data provide quantitative insight into the film formation mechanisms and correlate reaction conditions, cross-sectional nanostructure, and performance of the PA active layer in RO membranes for desalination.
AB - The structure and hydration of polyamide (PA) membranes are investigated with a combination of neutron and X-ray reflectivity, and their performance is benchmarked in reverse osmosis water desalination. PA membranes are synthesized by the interfacial polymerization of m-phenylenediamine (MPD) and trimesoyl chloride (TMC), varying systematically reaction time, concentration, and stoichiometry, to yield large-area exceptionally planar films of ≈10 nm thickness. Reflectivity is employed to precisely determine membrane thickness and roughness, as well as the (TMC/MPD) concentration profile, and response to hydration in the vapor phase. PA film thickness is found to increase linearly with reaction time, albeit with a nonzero intercept, and the composition cross-sectional profile is found to be uniform, at the conditions investigated. Vapor hydration with H2O and D2O from 0 to 100% relative humidity results in considerable swelling (up to 20%), but also yields uniform cross-sectional profiles. The resulting film thickness is found to be predominantly set by the MPD concentration, while TMC regulates water uptake. A favorable correlation is found between higher swelling and water uptake with permeance. The data provide quantitative insight into the film formation mechanisms and correlate reaction conditions, cross-sectional nanostructure, and performance of the PA active layer in RO membranes for desalination.
KW - neutron reflectivity
KW - polyamide active layers
KW - reverse osmosis
U2 - 10.1002/adfm.201701738
DO - 10.1002/adfm.201701738
M3 - Article
AN - SCOPUS:85030307883
VL - 27
SP - 1
EP - 10
JO - Advanced Functional Materials
JF - Advanced Functional Materials
SN - 1616-301X
IS - 37
M1 - 1701738
ER -