A highly selective PEGBEM-g-POEM comb copolymer membrane for CO2/N2 separation

Orientation of an Amphiphilic Copolymer to a Lamellar Structure on a Hydrophobic Surface and Implications for CO2 Capture Membranes

“…In fact, pristine PTMSP has ah igh free volume and has ahigh diffusivity with glassy and amorphous physical properties.Incomparison, the polymerized PEGBEM demonstrated not only ah igh CO 2 solubility,w hich was induced by the presence of ester or ether groups according to Lewis acidbase chemistry,b ut also exhibited high crystallinity,w hich hindered the diffusion of gas in the matrix. Our previous work [30] verified that am oderately controlled PEGBEM crystallinity could give rise to ah igh CO 2 selectivity performance.H owever, interfacial defects may have formed in the highly crystalline phases of PEGBEM, resulting in low selectivity.U ntil the PEGBEM grafting was repeated three times,t he N 2 permeance gradually decreased because of the crystalline phase,w hich was induced by the polymerized PEGBEM. TheCO 2 permeance also decreased but to alesser extent.…”

“…It should be noted that the ethylene oxide units in the PEGBEM interact well with CO 2 molecules and give rise to enhanced CO 2 solubility. [29,30] The sample that was treated twice with PEGBEM also exhibited adecreased gas permeance,together with increased selectivity.T his behavior was maintained until the grafting process was repeated three times,w here aC O 2 permeance of 166.9 GPU and CO 2 /N 2 selectivity of 77.2 were obtained. In the case of excessively repeated grafting processes,t he CO 2 permeance decreased, whereas the N 2 permeance hardly changed, causing the selectivity to decrease to 41.3.…”

“…PEGBEM is al iquid in its macromonomer state,b ut ac rystalline solid state can be obtained when it is polymerized. [29,30] Thesolid-state is attributed to the presence of sequential methylene chains,w hich can form ac rystalline phase by stacking with each other. [31][32][33] Along with these methylene chains,s everal ethylene oxide groups are present in PEGBEM, which give rise to the high solubility of CO 2 molecules by Lewis acid-base interactions.I no ur previous work, [29] PEGBEM exhibited higher CO 2 solubility (0.12 mmol cm À3 )t han PEBAX (0.095 mmol cm À3 ), which is ac ommercially available block copolymer and well-known for CO 2 -philic properties.…”

“…Thes uccessful surface polymerization and creation of favorable molecular interactions were characterized using Fourier transform infrared (FTIR) spectroscopy,asshown in Figure 1a. [29,30,[34][35][36] Ad etailed discussion is given in the Supporting Information. TheF TIR spectra were measured after the PEGBEM grafting of the PTMSP (PtP) layers via free radical polymerization with 2,2'-azobis(2-methylpropionitrile) (AIBN).…”

Orientation of an Amphiphilic Copolymer to a Lamellar Structure on a Hydrophobic Surface and Implications for CO2 Capture Membranes

“…Herein, we suggest an effective way to improve the CO 2 separation property of PTMSP membranes based on the surface graft copolymerization of poly(ethylene glycol)behenyl ether methacrylate (PEGBEM) in the presence of allylamine (Scheme ). PEGBEM is a liquid in its macromonomer state, but a crystalline solid state can be obtained when it is polymerized . The solid‐state is attributed to the presence of sequential methylene chains, which can form a crystalline phase by stacking with each other .…”