Composite Membrane with PEI and PHMB for Endotoxin Retention
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Solution Overview
Problem
Existing membrane manufacturing processes, particularly phase inversion processes, are limited in achieving optimal pore sizes and surface properties, which affects membrane separation performance and absorption properties.
Innovation Solution
A composite membrane is developed comprising a porous polymeric support structure coated with a polyethylene imine (PEI) layer and grafted with poly(hexamethylene biguanide) (PHMB), enhancing surface properties and filtration efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If phase inversion process is used for membrane manufacturing, then membrane production is achieved, but limitations in pore sizes and surface properties are imposed
Solution Approach 1:
The patent applies preliminary action by coating the membrane surface with polyethyleneimine (PEI) before final use. This pre-coating step modifies the surface properties to enhance endotoxin retention capabilities, addressing the limitation of the phase inversion process in achieving optimal surface properties. The PEI layer is applied in advance to ensure the membrane has the desired surface characteristics for specific filtration applications.
Solution Approach 2:
The patent employs parameter changes by modifying the surface chemistry through PEI coating and subsequent PHMB grafting. These chemical modifications change the surface parameters (charge, hydrophilicity, reactivity) to improve endotoxin retention. The phase inversion process parameters are also optimized to achieve desired pore structures, demonstrating parameter changes to overcome the inherent limitations of the manufacturing process.
2Reliability
If membrane post-functionalization is applied, then surface functionalities are enhanced, but process complexity increases
Solution Approach 1:
The patent extracts the endotoxin retention functionality from the bulk membrane material and concentrates it at the surface through PEI coating and PHMB grafting. This separation allows the bulk membrane to maintain its filtration properties while the surface provides enhanced endotoxin retention, simplifying the overall design by localizing specific functions to where they are most needed.
Solution Approach 2:
The patent creates a composite membrane structure combining the base polymer matrix with PEI coating layer and grafted PHMB molecules. This composite approach allows integration of multiple functions: the base membrane provides mechanical strength and pore structure, while the PEI-PHMB composite layer provides enhanced endotoxin retention. The composite structure resolves the complexity issue by systematically organizing different materials to perform specific functions.
3Reliability
If polyethylene imine coating and PHMB grafting are applied, then endotoxin retention is improved, but mechanical stability may be affected
Solution Approach 1:
The patent applies local quality by concentrating the PEI coating and PHMB grafting specifically at the membrane surface rather than throughout the bulk material. This localized modification ensures that endotoxin retention enhancement is achieved at the interface where it is most critical, while the bulk membrane retains its original mechanical properties and structural integrity. The surface-modified layer is designed to be thin enough to preserve overall membrane strength.
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 composite membrane exhibits improved retention of endotoxins, high mechanical stability, and maintains filtration properties without deterioration, making it suitable for liquid filtration applications.
Implementation Method 1
a polyethylene imine (PEI) layer coated onto the support structure
Implementation Method 2
poly(hexamethylene biguanide) (PHMB) grafted to the coating layer of the support structure
Implementation Method 3
membrane separation performance (separation by size exclusion) as well as absorption properties (chemical and physical interactions of the medium and the membrane surface)
Data Source
AI summary
The present disclosure relates to a composite membrane comprising a porous support structure, a polyethylene imine (PEI) layer coated onto the support structure, and poly(hexamethylene biguanide) (PHMB) grafted to the coating layer of the support structure. The present disclosure also provides a method to produce the composite membrane. The present disclosure also provides a filtration and/or diffusion device comprising the composite membrane.