AC-PDMS TFC Membrane UV Curing for Gas Separation
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Solution Overview
Problem
The preparation of defect-free ultra-thin PDMS membranes is challenging due to difficulties in controlling the processability of the casting solution and pore penetration, which affects the mechanical interlocking and separation performance in applications like gas separation.
Innovation Solution
The use of acryloyloxy-terminated polydimethylsiloxane (AC-PDMS) with a UV-induced addition reaction for rapid curing of the selective layer, inhibiting pore penetration and enabling the formation of a complete and defect-free membrane with improved separation performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a PDMS casting solution with low concentration is used to prepare an ultra-thin selective layer, then the membrane thickness is reduced, but the solution penetrates into pores of the support causing serious pore penetration
Solution Approach 1:
The patent changes the chemical structure of PDMS from hydroxy-terminated to acryloyloxy-terminated, enabling UV-induced rapid polymerization. This parameter change allows the use of low-concentration casting solutions to form ultra-thin selective layers without pore penetration, as the rapid curing prevents solution infiltration into support pores
Solution Approach 2:
The patent replaces thermal curing with UV-induced photo-polymerization. This substitution enables rapid curing of the casting solution before it can penetrate into support pores, while still achieving complete crosslinking and forming a defect-free ultra-thin selective layer
2Object-generated harmful factors
If a high-permeability polymer is used to prepare a transition layer on the surface of a support, then pore penetration is prevented, but the membrane-forming process is complicated
Solution Approach 1:
The patent removes the intermediate transition layer from the membrane structure. By using acryloyloxy-terminated PDMS that cures rapidly under UV irradiation, the solution forms a complete selective layer directly on the support without penetrating into pores, eliminating the need for a separate transition layer and simplifying the overall membrane-forming process
3Reliability
If a condensation reaction between traditional hydroxy-terminated polydimethylsiloxane and a crosslinker is used, then the selective layer is formed, but the reaction rate is slow allowing pore penetration to occur
Solution Approach 1:
The patent changes the terminal functional groups of PDMS from hydroxy to acryloyloxy, enabling addition polymerization under UV irradiation instead of slow condensation reaction. This parameter change increases the reaction rate by 1 to 2 orders of magnitude, allowing the selective layer to form before pore penetration can occur
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The AC-PDMS-based TFC membrane achieves a high CO2 penetration rate of 9,635 GPU and CO2/N2 selectivity of 11.5, simplifying the preparation process and enhancing molecular separation efficiency.
Implementation Method 1
a crosslinking mode of such a silicone rubber is based on an addition reaction of an acryloxy-terminated monomer under ultraviolet (UV) irradiation
Implementation Method 2
TFC membranes show the obvious advantage of rapid and selective penetration during an actual process
Data Source
AI summary
The present disclosure provides an acryloyloxy-terminated polydimethylsiloxane (AC-PDMS)-based thin-film composite (TFC) membrane, and a preparation method and use thereof. In the preparation method, a simple ultraviolet (UV)-induced monomer polymerization strategy based on high UV reactivity among acryloyloxy groups is adopted to prepare the AC-PDMS-based TFC membrane. The high UV reactivity among AC-PDMS monomers can induce the rapid curing of a casting solution to enable the formation of an ultra-thin selective layer and the inhibition of pore penetration for a substrate. By optimizing a UV wavelength, an irradiation time, and a polymer concentration, the prepared AC-PDMS-based TFC membrane has a CO2 penetration rate of 9,635 GPU and a CO2/N2 selectivity of 11.5. The UV-induced monomer polymerization strategy based on material properties provides a novel efficient strategy for preparing an ultra-thin PDMS-based membrane, which can be used for molecular separation.