Photocurable Membrane Surface Features for High-Aspect-Ratio Printing
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Solution Overview
Problem
Existing curable compositions struggle to efficiently form topographical features on membrane surfaces for osmosis and reverse-osmosis applications, requiring multiple passes for height, leading to slow printing speeds and inadequate aspect ratios, while maintaining chemical and temperature resistance, bond strength, and flexibility.
Innovation Solution
A photocurable composition with a Thixotropic Index (TI) of 2 to 15 and viscosity of 10,000 to 500,000 centipoise at 10 s−1, allowing for high-speed stencil or screen printing with aspect ratios of 0.2 to 2, ensuring the features maintain shape during removal of the stencil or screen.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional curable compositions are used for printing topographical features, then chemical resistance and durability are improved, but the aspect ratio and shape retention during printing deteriorate
Solution Approach 1:
The patent modifies the rheological parameters of the curable composition by adding rheology modifying components. Specifically, it achieves a Thixotropic Index (TI) of 2-15 and viscosity of 10,000-500,000 cP at 10 s^-1, which allows the composition to maintain its shape during printing while still being printable. This parameter change resolves the contradiction between chemical resistance and aspect ratio by optimizing the flow and structural properties of the composition.
Solution Approach 2:
The patent creates a composite curable composition by combining conventional curable components (providing chemical resistance) with rheology modifying components (providing shape retention). This composite approach allows both requirements to be met simultaneously - the base composition provides durability while the added rheology modifiers enable high aspect ratio formation with TI of 2-15.
2Manufacturing precision
If multiple passes of curable composition deposition are used to build required heights, then the aspect ratio is improved, but the printing speed and production efficiency deteriorate
Solution Approach 1:
By changing the rheological parameters to achieve TI of 2-15 and high viscosity (10,000-500,000 cP), the composition can form high aspect ratio features (0.2-2.0) in a single printing pass. The thixotropic properties allow the material to be deposited efficiently at high speed while maintaining its shape, eliminating the need for multiple slow passes.
Solution Approach 2:
The rheology modifying components are pre-added to the composition to provide the necessary flow and structural properties before printing. This preliminary preparation ensures that during high-speed printing, the composition automatically maintains its shape and achieves the required aspect ratio in one pass, without requiring subsequent corrective passes.
3Productivity
If jet printing is used to double the print speed, then productivity is improved, but the aspect ratio deteriorates due to impact velocity
Solution Approach 1:
The patent optimizes the viscosity parameter to 10,000-500,000 cP at 10 s^-1 and Thixotropic Index to 2-15, which allows the composition to withstand jet printing impact velocities while maintaining shape. The high viscosity prevents excessive spreading upon impact, and the thixotropic properties ensure rapid structure recovery, achieving both high print speed and high aspect ratio (0.2-2.0).
4Strength
If the curable composition is made too brittle to prevent membrane damage during rolling, then strength is improved, but the spacing function deteriorates due to compression under pressure
Solution Approach 1:
The composite curable composition combines strong bonding agents with rheology modifiers and flexible components. This creates a material that has both high bond strength to the membrane and sufficient flexibility to maintain spacing under pressure. The rheology modifying components contribute to this balance by providing structural integrity while allowing controlled deformation.
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 method enables high-speed production of topographical features with maintained aspect ratios and shape, optimizing membrane spacing and operation efficiency, reducing fouling, and enhancing membrane lifespan.
Implementation Method 1
curing the curable composition
Implementation Method 2
a Thixotropic Index (TI) of 2 to 15 and viscosity of 10,000 to 500,000 centipoise at 10 s−1
Data Source
AI summary
Photocurable compositions and methods of preparation and use of such compositions. More particularly, photocurable compositions useful for forming topographical features on surfaces such as membrane surfaces. Methods of forming topographical features on a membrane surface using photocurable compositions.