Support-Free Interfacial Polymerization for Reverse Osmosis Membranes
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Solution Overview
Problem
Current reverse osmosis membranes using interfacial polymerization are limited by the characteristics of the support material, leading to uneven surface formation and poor chemical durability, restricting their application and performance.
Innovation Solution
A method for manufacturing a composite membrane with a selective layer formed through interfacial polymerization at a free interface, independent of a support, by dissolving organic monomers in immiscible solutions and adhering the polymerized layer to a support, allowing for precise control over the selective layer's structure and properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If interfacial polymerization is performed on a support, then a selective layer can be formed, but the structure and properties of the selective layer are absolutely dependent on the support characteristics, limiting product specification expansion
Solution Approach 1:
The patent extracts the selective layer formation process from the support, performing interfacial polymerization in a support-free environment. The selective layer is formed at the interface between immiscible solutions without direct contact with the support during polymerization, thereby decoupling the selective layer structure from support characteristics. After formation, the layer is subsequently adhered to the support, allowing independent optimization of both components.
2Reliability
If conventional interfacial polymerization is used on a support, then a polyamide selective layer can be formed, but the surface becomes uneven and chemical durability is poor
Solution Approach 1:
The patent introduces an intermediary step where the selective layer is first formed in a support-free environment at the interface between immiscible solutions, allowing uniform polymerization without support interference. This intermediate selective layer structure serves as a mediator that is subsequently adhered to the support, preventing direct negative interaction between the support and the polymerization process, thereby achieving both surface uniformity and chemical durability.
3Stability of the object's composition
If a polysulfone support with small pore structure is used, then high hydrophobicity is achieved, but the selective layer does not form smoothly and application fields are limited
Solution Approach 1:
The patent segments the membrane manufacturing process into two independent stages: (1) formation of the selective layer through interfacial polymerization in a support-free environment where uniform polymerization occurs without support interference, and (2) subsequent adhesion of the formed selective layer to the support. This segmentation allows the selective layer to form smoothly regardless of support pore structure, while still achieving the desired hydrophobicity from the polysulfone support.
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
This approach results in a thinner, more uniform selective layer with improved water flux and contamination resistance, enabling the production of membranes with enhanced performance and expanded application fields, such as seawater desalination and water treatment.
Implementation Method 1
a polyamide selective layer is formed by bringing a porous support into contact with an organic monomer solution, then bringing them in contact with other immiscible organic monomer solutions and thus inducing an interfacial polymerization reaction between two organic monomers
Data Source
AI summary
The present invention relates to a method for manufacturing a composite membrane using a selective layer prepared through the interfacial polymerization (support-free interfacial polymerization) on a free interface without a support and, more specifically, to a method for manufacturing a composite membrane comprising a reverse osmotic membrane, which is obtained by preparing a selective layer through a spontaneous reaction of two organic monomers on an interface between two immiscible solutions and allowing the selective layer to adhere to a support. By employing the method for manufacturing a composite membrane having a selective layer prepared through the support-free interfacial polymerization according to the present invention, a high-functional reverse osmotic membrane can be prepared using various supports other than a conventional polysulfone support, thereby extending the application range of the reverse osmotic membrane, which has been restricted due to low chemical resistance of polysulfone. In addition, the preparation method for the selective layer can be controlled more precisely than a conventional method, and the analysis of components (selective layer, support, and interface) of the composite membrane is easy.