Robust and Elastic Polymer Membranes with Tunable Properties for Gas Separation

Abstract

Polymer membranes with the capability to process a massive volume of gas are especially attractive for practical applications of gas separation. Although much effort has been devoted to develop novel polymer membranes with increased selectivity, the overall gas-separation performance and lifetime of membrane are still negatively affected by the weak mechanical performance, low plasticization resistance and poor physical aging tolerance. Recently, elastic polymer membranes with tunable mechanical properties have been attracting significant attentions due to their tremendous potential applications. Herein, we report a series of urethane-rich PDMS-based polymer networks (U-PDMS-NW) with improved mechanical performance for gas separation. The cross-link density of U-PDMS-NWs is tailored by varying the molecular weight (M) of PDMS. The U-PDMS-NWs show up to 400% elongation and tunable Young's modulus (1.3-122.2 MPa), ultimate tensile strength (1.1-14.3 MPa), and toughness (0.7-24.9 MJ/m). All of the U-PDMS-NWs exhibit salient gas-separation performance with excellent thermal resistance and aging tolerance, high gas permeability (>100 Barrer), and tunable gas selectivity (up to α[P/P] ≈ 41 and α[P/P] ≈ 16). With well-controlled mechanical properties and gas-separation performance, these U-PDMS-NW can be used as a polymer-membrane platform not only for gas separation but also for other applications such as microfluidic channels and stretchable electronic devices.

Superstretchable, Self‐Healing Polymeric Elastomers with Tunable Properties

“…The different thermal behavior of U-PDMS-Es compared with that of PDMS-NH 2 should be attributed to the effect of chemical/physical crosslinking which limits the mobility of polymer chains and growth of crystalline structure. [39,41] Moreover, the presence of only one T g in the heating run of TM-DSC indicates no significant phase separation within the U-PDMS-Es. The absence of a periodic phase separated structure was also confirmed by the small-angle X-ray scattering (SAXS) spectra of U-PDMS-Es (Figure S5).…”

“…With the normalized FT-IR absorption band corresponding to the C-Si bond at 1257 cm -1 , [39] significantly decreased intensity of the absorption bands lying at 3511-3120 cm -1 (N-H stretching), 1740-1625 cm -1 (C=O stretching) and 1561 cm -1 (associated N-H bending) manifest the decreased intensity of the urethane groups. [12] The U-PDMS-Es exhibit enhanced thermal stability with increased molecular weight of PDMS, and no significant weight loss was observed for U-PDMS5.0K-E up to 450 °C (Figure S3).…”

“…PDMS was selected as the polymer backbone because of its intrinsic high stretch-ability, good thermal/chemical stability and low glass-transition temperature (T g ~-123 o C). [33,39,40] The low T g is important to enable the chain mobility and maintain the self-healing properties of the elastomers obtained. [33] Instead of using pure amine terminated PDMS, a tetra-diethylenetriamine terminated PDMS (TDA-PDMS, Scheme 1) serves as the cross-linker/branching point of the final polymeric elastomers as well as increases hydrogen bonding density.…”

3D Printed Multifunctional, Hyperelastic Silicone Rubber Foam

“…The intrinsic flexible/hydrophobic siloxane chain offers silicone rubber excellent elasticity, biocompatibility, water resistance, and high gas permeability . Covalent crosslinking provides silicone network with exceptional mechanical strength, as well as remarkable chemical resistance and thermal stability . The large internal space affords the porous silicone with low density, high surface area, which allows additional deformation freedom, achieving extraordinary deformability and elasticity .…”

Stretchable gas barrier films achieved by hydrogen-bond self-assembly of nano-brick multilayers

“…[13][14][15][16][17][18] Layer-by-layer (LBL) assembly is an effective method to prepare gas barrier coatings through nanoscale control of film architecture. [19][20][21][22][23] Electrostatic layer assembly technology is the earliest and most common method for constructing multilayer films. 13,24 This method is suitable for assembly between oppositely charged elements, such as polymer electrolytes, inorganic nanoparticles, two-dimensional (2D) nanoplatelets, etc.…”