PVDF Membrane with Fluorinated Silane Layer for Anti-Fouling
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Solution Overview
Problem
Conventional membranes used for water desalination, such as those made from hydrophobic polymers like PVDF, are prone to fouling by organic pollutants and contaminants, reducing their hydrophobic characteristics and leading to shorter service lifetimes and lower throughput.
Innovation Solution
The development of super-hydrophobic, oleo-phobic, and anti-fouling polymer-based membranes with a fluorinated silane layer, formed through a phase inversion process using a PVDF-based solvent and PVP modifying agent, along with metal-based nanoparticles, which enhances mechanical strength and repels surface contaminants.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional hydrophobic polymer membranes are used for desalination, then water separation is achieved, but the membranes are prone to fouling by organic pollutants which reduces their service lifetime and throughput
Solution Approach 1:
The patent combines PVDF polymer matrix with fluorinated silane coating to create a composite membrane structure. The PVDF provides mechanical strength and base hydrophobicity, while the fluorinated silane layer adds enhanced oleophobicity and anti-fouling properties, resolving the contradiction between maintaining hydrophobic separation function and resisting organic pollutant fouling
Solution Approach 2:
The patent modifies the surface energy parameters of the membrane by introducing fluorinated silane groups with low surface energy. This changes the contact angle parameters (water contact angle >150°, oil contact angle >100°) to achieve super-hydrophobic and oleophobic states, preventing organic pollutant adhesion while maintaining water separation capability
2Productivity
If hydrophobic polymer membranes are used, then water desalination is enabled, but organic contaminants reduce hydrophobic characteristics and lower throughput
Solution Approach 1:
The fluorinated silane coating is applied in advance to the PVDF membrane surface to create a pre-protective barrier. This preliminary anti-action prevents organic contaminants from adhering to the membrane, maintaining hydrophobic characteristics and ensuring sustained high throughput during desalination operations
Solution Approach 2:
The patent utilizes the low surface energy property of fluorinated silane groups to convert potential contamination into beneficial anti-fouling behavior. The fluorinated layer attracts and repels organic contaminants, preventing them from reaching and degrading the PVDF membrane's hydrophobic characteristics, thus maintaining throughput
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 membranes exhibit improved hydrophobic and oleophobic properties, reducing fouling and extending service life, while maintaining high water and oil contact angles, thus enhancing desalination efficiency and throughput.
Implementation Method 1
super-hydrophobic, oleo-phobic characteristics at high contact angles
Implementation Method 2
super-hydrophobic, oleo-phobic characteristics at high contact angles
Implementation Method 3
membranes, which are becoming a common commodity to extract freshwater from saline feedwater. The feedwater is forced onto the surface of a membrane, which selectively passes water and retains salts
Implementation Method 4
Phase inversion is a process of controlled polymer transformation from a liquid phase to solid phase
Data Source
AI summary
Polymer-based membranes and methods for fabricating membranes are described. The methods include forming a casting solution featuring a plurality of titanium dioxide (TiO2) nanoparticles, a polyvinylidene fluoride (PVDF)-based solvent, and a polyvinylpyrrolidone (PVP)-based modifying agent, dispersing the casting solution to form a first element, generating a plurality of active sites on a surface of the first element, and forming a polymer-based membrane by exposing the surface of the first element to a fluorosilane composition to form a fluorosilane layer on the surface, where the fluorosilane composition includes a silane compound having at least one alkyl substituent that includes between 9 and 21 fluorine atoms.