Asymmetric Microfiltration Membrane with Embedded Separating Layer
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing microfiltration membranes based on sulfone polymers face challenges with mechanical susceptibility, limited hydrophilicity, and moderate permeability, which affects their dirt-loading capacity and stability, especially when used with aqueous media.
Innovation Solution
An integrally asymmetric membrane with a hydrophobic aromatic sulfone polymer and a hydrophilic second polymer, featuring a porous structure with a minimal pore size separating layer protected within the membrane wall, an asymmetrical region near one surface, and a highly open-pored structure near the other surface, enhancing mechanical stability and permeability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a separating layer with minimal pore size is placed on the membrane surface, then filtration precision is improved, but mechanical susceptibility increases
Solution Approach 1:
The separating layer with minimal pore size is nested within the membrane wall rather than placed on the surface. The patent describes an 'integrally asymmetric membrane' where the separating layer is embedded in the membrane structure, protected by the surrounding membrane material. This nesting approach maintains filtration precision while shielding the fragile separating layer from mechanical damage.
Solution Approach 2:
The separating layer is positioned in the interior dimension of the membrane wall rather than on the two-dimensional surface. The patent specifies that the separating layer is located 'in the wall's interior' with asymmetrical regions extending toward both surfaces, effectively moving the critical filtration layer from a surface position to a three-dimensional interior position that provides mechanical protection.
2Stability of the object's composition
If hydrophobic sulfone polymers are used for membrane fabrication, then chemical stability is improved, but hydrophilicity deteriorates
Solution Approach 1:
The membrane is fabricated as a composite material combining hydrophobic sulfone polymers (providing chemical stability) with hydrophilic polymers or modified sulfone polymers (providing hydrophilicity). The patent describes using 'sulfone polymers, in particular modified sulfone polymers' and adding 'a water-soluble polymer' to the casting solution, creating a composite structure that simultaneously achieves chemical stability and hydrophilicity for aqueous media filtration.
3Measurement precision
If asymmetric structure with skin layer is implemented, then separation performance is improved, but mechanical stability deteriorates
Solution Approach 1:
The membrane maintains its asymmetric structure with different pore sizes in different regions, but redistributes the asymmetry symmetrically toward both surfaces. The patent describes 'a first asymmetrical region' and 'a second asymmetrical region' extending from the interior separating layer toward each surface, creating a balanced asymmetric structure that preserves separation performance while distributing mechanical stress more evenly.
Solution Approach 2:
The membrane is segmented into distinct functional regions: an interior separating layer with minimal pore size, and two asymmetrical regions extending toward each surface with progressively larger pores. This segmentation allows the critical separating layer to be protected in the interior while the outer regions provide mechanical strength and gradual pore size transitions.
4Productivity
If pore size increases toward membrane surfaces, then permeability is improved, but separation precision deteriorates
Solution Approach 1:
Different regions of the membrane are assigned different pore sizes according to their functional requirements. The interior separating layer has minimal pore size for high separation precision, while the asymmetrical regions toward the surfaces have progressively larger pores for improved permeability. This local differentiation of pore size quality allows simultaneous optimization of both separation precision and permeability in different spatial locations.
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 membrane achieves high dirt-loading capacity, mechanical strength, and high transmembrane flow with maintained hydrophilicity, allowing for efficient filtration of aqueous solutions and proteins without significant permeability reduction over time.
Implementation Method 1
Microporous polymer membranes are used in a wide range of industrial, pharmaceutical, or medical applications for high-precision filtration
Implementation Method 2
membranes made of hydrophobic material have a strong, non-specific ability to adsorb, due to which in use often results rapid covering of the membrane surface by predominantly higher-molecular components of the liquid to be filtered
Data Source
AI summary
Method for producing this membrane from a casting solution comprising the hydrophobic first sulfone polymer and the hydrophilic second polymer in a solvent system, the method comprising the steps of pouring the casting solution, conditioned to a molding temperature, onto a carrier to form a film, which carrier has a temperature that is higher in comparison to the molding temperature, conveying the film through a climate-controlled zone, initiating the coagulation in a coagulation bath for the formation of a membrane structure, withdrawing the membrane structure from the carrier with a speed that is increased in comparison to the carrier speed, stabilizing, extracting, and subsequently drying the membrane.