Block Copolymer Separation Membrane with Thin Selective Layer
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Solution Overview
Problem
Current methods for producing ultrafiltration membranes struggle to achieve a balance between high selectivity and high flow rates while being cost-effective and scalable, with existing processes being complex, expensive, and difficult to scale up.
Innovation Solution
A method involving a polymer solution of amphiphilic block copolymers in a single solvent, formed into a film using spraying or capillary methods, followed by phase inversion with a non-solvent, which directly forms pores and results in a thin, highly selective, and high-flow membrane layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If complex electrochemical processes or template processes are used to produce isoporous membranes, then narrow pore size distribution and high selectivity are achieved, but manufacturing complexity and production costs increase significantly
Solution Approach 1:
The patent changes the fundamental parameter of pore formation from electrochemical or template-based methods to a self-organizing phase separation process. By controlling polymer concentration, solvent evaporation rate, and non-solvent exposure, isoporous structures form spontaneously without complex manufacturing steps, achieving narrow pore size distribution through thermodynamic self-organization rather than engineered templates
Solution Approach 2:
The block copolymer system performs self-service by automatically organizing into micellar structures with well-defined pore sizes through phase separation. The amphiphilic blocks spontaneously form the desired porous morphology without requiring external templates, electrochemical fields, or complex processing equipment, thereby eliminating manufacturing complexity while maintaining high pore size precision
2Manufacturing precision
If thick membrane layers are used to achieve sufficient selectivity, then separation performance improves, but flow rate decreases due to higher membrane resistance
Solution Approach 1:
The patent applies local quality by creating a thin membrane layer (reducing overall resistance) while concentrating the separation function in the well-defined isoporous structure. The uniform pore size distribution ensures that every local region contributes efficiently to separation, allowing thin membranes to achieve the same selectivity as thicker membranes would provide through bulk thickness alone
Solution Approach 2:
The invention utilizes the isoporous structure formed by block copolymer phase separation to create a membrane with uniform pore sizes throughout the thin layer. This porous architecture provides high surface area and efficient mass transport pathways, enabling thin membranes to simultaneously achieve high selectivity (through uniform pore filtering) and high flow rates (through reduced thickness and optimized pore connectivity)
3Strength
If conventional membrane production methods are used, then adequate mechanical stability is achieved, but layer thickness and membrane resistance increase, reducing flow rate
Solution Approach 1:
The patent employs thin film technology by forming membranes directly on porous support substrates using a spray coating process. The block copolymer solution is applied as a thin layer that dries to form a continuous, stable film with thickness optimized for low resistance. The porous support provides mechanical strength while the thin active layer minimizes resistance, achieving high flow rates without sacrificing stability
Data Source
Figure 1(a)~1(c)
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AI summary
The invention relates to a method for producing a separation membrane comprising the steps of: - providing a polymer solution of at least one block copolymer in at least one solvent for the block copolymer, - forming a film from the polymer solution on a support substrate by means of a spraying process, a pressure process, or a process based on capillary effects, and - phase inversion of the film to form the separation membrane. The separation membrane that can be produced by the method according to the invention comprises a porous support substrate and at least one separation-active layer arranged on the support substrate, which has a layer thickness of at most 10 µm.