Blood Filter with Sub-20nm Pores via Block Copolymer Mask
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Solution Overview
Problem
Current blood filters face challenges in achieving high selectivity, throughput, and cost-effectiveness while integrating with electronic circuits, particularly CMOS circuits, due to limitations in pore size control, uniformity, and membrane thickness.
Innovation Solution
A method involving a block copolymer layer that is converted into a mask through selective domain removal, allowing for precise etching of pores with sizes below 20 nm, enabling efficient filtration and integration with CMOS technology.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional filtration methods are used, then manufacturing simplicity is maintained, but pore size control precision and uniformity deteriorate
Solution Approach 1:
The block copolymer layer is prepared in advance through self-assembly to form a precise nanoscale pattern that serves as a mask. This preliminary structuring enables subsequent etching to achieve uniform sub-20nm pores without requiring complex real-time control during the etching process itself.
Solution Approach 2:
A block copolymer layer acts as an intermediary mask between the lithography pattern and the final pore structure. The BCP self-assembles to amplify the pattern features and provides a self-organized template that guides the formation of uniform nanoscale pores through selective etching.
2Productivity
If membrane thickness is reduced to improve throughput, then filtration speed increases, but mechanical strength and selectivity deteriorate
Solution Approach 1:
The membrane structure is optimized with locally varied properties: the pore distribution and size are precisely controlled in the filtration layer to maximize throughput, while the support layer provides enhanced mechanical strength. This local differentiation allows thin active layers for high flux without compromising overall membrane integrity.
3Manufacturing precision
If pore size is reduced to improve selectivity, then filtration precision increases, but throughput deteriorates
Solution Approach 1:
The membrane utilizes a controlled porous structure with uniform sub-20nm pores created through the BCP mask etching process. The high uniformity and narrow size distribution of these pores enable precise size-based separation while maintaining adequate flux, as the consistent pore dimensions prevent clogging and ensure predictable transport properties.
4Manufacturing precision
If advanced nanofabrication methods are used to achieve uniform sub-20nm pores, then pore uniformity improves, but manufacturing cost increases
Solution Approach 1:
The block copolymer system performs self-service by automatically self-assembling into uniform nanoscale domains without requiring external guidance or complex alignment steps. The BCP's inherent microphase separation creates the mask pattern autonomously, eliminating the need for expensive electron beam lithography or other advanced patterning tools.
Solution Approach 2:
The pore size and uniformity are controlled by changing parameters of the block copolymer system itself - such as the block length ratio, molecular weight, and composition ratio - rather than by adjusting complex lithography parameters. This allows precise tuning of pore dimensions through material selection and processing conditions like annealing temperature and solvent choice.
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 produces filters with small, uniformly sized pores, high throughput, and cost-effectiveness, suitable for applications like dialysis and lab-on-a-chip systems, while preventing large blood components from passing through, thus enhancing filtration efficiency and portability.
Implementation Method 1
Converting the BCP layer to a mask may comprise a self-assembly process. Herein, the BCPs may arrange to form domains, e.g. two or more types of domains. The formation of domains may be caused by the polymers of the different block types repelling each other
Implementation Method 2
etching pores through the first layer in regions exposed by the mask
Implementation Method 3
Blood passing through the pores may be filtered by the pores, when the blood filter is in use. Alternatively, the blood may be filtered by impurities of the blood being allowed to pass through the filter while at least some proteins of the blood are prevented from passing through the filter
Data Source
AI summary
A method for producing a blood filter, the blood filter being a filter for filtering blood, the method comprisingproviding a first layer;providing a block copolymer layer above the first layer;converting the block copolymer layer to a mask by selectively removing domains of the block copolymer layer;etching pores through the first layer in regions exposed by the mask;wherein a pore size is below 20 nm, the pore size preferably being 6.6 nm or smaller.