Isoporous Copolymer Membrane on Porous Substrate for Uniform Filtration
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Solution Overview
Problem
Existing porous membranes exhibit non-uniform pore size distribution and require solvent exchange phase inversion steps, limiting their flux and size exclusion capabilities.
Innovation Solution
Formation of an isoporous membrane on a porous substrate using a triblock or pentablock copolymer composition, leveraging capillary action for rapid solvent removal and avoiding traditional solvent-induced phase separation, resulting in a uniform pore structure throughout the membrane thickness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional porous membranes are used, then manufacturing is simpler, but pore size distribution is non-uniform and flux performance is limited
Solution Approach 1:
The patent uses triblock or pentablock copolymers with specific block ratios (e.g., 20:80, 30:70, 40:60) to control micelle formation and pore size. By changing the polymer composition parameters and solvent removal conditions, uniform isoporous structures are achieved throughout the membrane thickness without requiring complex phase inversion steps
Solution Approach 2:
The patent employs composite copolymer systems where hydrophilic blocks (e.g., polyethylene oxide) and hydrophobic blocks (e.g., polystyrene) self-assemble into micellar structures. This composite approach at the molecular level creates uniform pores while simplifying the manufacturing process by eliminating the need for separate phase inversion steps
2Productivity
If solvent exchange phase inversion is used, then membrane formation is achieved, but the process is more complex and time-consuming
Solution Approach 1:
The patent extracts the essential function of pore formation from the complex solvent exchange phase inversion process. By using copolymer micelles that self-assemble during simple solvent removal, the patent eliminates the need for multiple solvent exchange steps while maintaining effective membrane formation
Solution Approach 2:
The copolymer micelles are pre-formed in the casting solution before membrane fabrication. This preliminary self-assembly means that pore structure formation occurs automatically during solvent removal, eliminating the need for subsequent phase inversion steps and significantly simplifying the overall process
3Reliability
If high polymer concentrations are used, then membrane structure is formed, but flux performance is reduced
Solution Approach 1:
The patent creates a highly porous isoporous structure where pores are uniformly distributed throughout the membrane thickness. This porous architecture provides both structural integrity and high flux performance by allowing efficient fluid transport through the membrane while maintaining mechanical stability
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 method achieves improved flux and size exclusion performance by creating a membrane with uniform pores, eliminating the need for solvent exchange phase inversion and reducing the reliance on high polymer concentrations.
Implementation Method 1
leveraging capillary action for rapid solvent removal
Implementation Method 2
improvements in flux and size exclusion at a given pore size
Data Source
AI summary
The present disclosure provides an article including an isoporous membrane disposed on a porous substrate. The isoporous membrane includes a triblock copolymer or a pentablock copolymer. The isoporous membrane has a thickness and is isoporous throughout its thickness. A method of making an article is also provided, which does not require a solvent exchange process. The method includes depositing a composition on a porous substrate, thereby forming a fdm, and removing at least a portion of the solvent from the film, thereby forming an isoporous membrane having numerous pores. The composition contains a solvent and solids including a triblock copolymer or a pentablock copolymer. The article advantageously can be hydrophilic and provides sharp molecular weight cut-offs and high flux.