A 7 nm Thick Polymeric Membrane With a H₂/CO₂ Selectivity of 200 That Reaches the Upper Bound

Abstract

Gelest, Inc., Morrisville, PA) were used as obtained. House-deionized water was purified using a Millipore Milli-Q-filtering system containing one carbon and two ion-exchange stages. Experimental methods that were used to (i) synthesize 5,11,17,23,29,35hexakis[(N,N,N-trimethylamonium)-N-methyl-37,38,39,40,41,42-hexakis-nhexadecyloxy-calix[6]arene chloride (i.e., Calix), (ii) deposit Langmuir-Blodgett (LB) bilayers of PAA-crosslinked Calix, 1 and 2 onto poly[1-(trimethylsilyl)-1-propyne] (PTMSP) supports or silicon wafers (silylated with n-octadecyltrichlorosilane, OTS), (iii) quantify gas permeabilities, and (iv) measure film thicknesses by ellipsometry were similar to those that have previously been described. [1][2][3] Ellipsometry measurements were made using VASE ellipsometer (J.A. Woollam Co., Inc., Lincoln, NE), equipped with variable wavelength ( from 250-1700nm) and angle of incidence (15º-90º) system, a λ of 632.8nm and an incidence angle of 70º were chosen for measurements. The refractive indices that were used to estimate the thickness of the OTS and the LB bilayers were both 1.46. All AFM measurements were made using a tapping mode atomic force microscopy

Metal–Organic Covalent Network Chemical Vapor Deposition for Gas Separation

“…Of note is that permeance data reported in this work are calculated based on the full thickness of the composite membrane, which is the sum of the PTMSP and MOCN thicknesses. This is in contrast to some other recently reported supported nanomaterial gas‐separation membranes, where the thickness of the base support layer is excluded from the calculation . While the gas permeance of uncoated PTMSP follows the sequence of CO 2 > H 2 > CH 4 > O 2 > N 2 , which can be ascribed to the combined effects of diffusion and sorption (e.g., CO 2 and CH 4 are more condensable), a more remarkable molecular sieving effect was observed for the MOCN‐coated membrane ( Figure a).…”

“…Gas‐Permeation Experiments : The procedure for the single and mixed‐gas permeation measurements were similar as described in detail elsewhere . A constant pressure setup was used for both the single and mixed‐gas permeation experiments.…”

Recent developments in membranes for efficient hydrogen purification

“…Then the same group prepared a 7 nm thick polymeric membrane via the similar method, and the only difference was that cationic surfactants was replaced by quaternary ammonium derivative of poly(maleic anhydride-alt-1-octadecene) [164]. The membrane displayed an extremely high H 2 /CO 2 selectivity of 200.…”

Gas Selective Ultrathin Organic Covalent Networks Synthesized by iPECVD: Does the Central Metal Ion Matter?

“…In addition, due to the inverse relation between the flux and thickness of the gas selective layer (Equation ), asymmetric or composite membranes with a typical skin layer thickness down to 100 nm have been the standard format for gas separation applications . Polymers, graphene, graphene oxides, and metal organic framework (MOF) nanosheets are some of the examples that have been successfully processed into thin gas selective films …”