Cross-Flow Filtration for Scalable Silver Nanowire Purification

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Solution Overview

Problem

Existing methods for purifying silver nanowires, such as sedimentation and dead-end filtration, are not scalable beyond small batches and do not produce high-purity nanowires with desired lengths, limiting their use in large-scale production of transparent conductors.

Innovation Solution

The method involves cross-flow filtration of silver nanowires using a filter with a mean mesh size of 20 to 40 µm, allowing for scalable production of silver nanowires with lengths of 30 µm to 90 µm and widths of 80 nm to 150 nm, and incorporating a vibration system to prevent clogging, enabling the production of high-purity nanowires suitable for transparent conductors.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If sedimentation and dead-end filtration are used to purify nanowires, then purification is achieved on small scale, but scalability is limited and purity is insufficient

Engineering Contradiction:
Improvenanowire purityVSAvoidproduction scalability
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The invention changes the filtration parameters by using cross-flow filtration with specific mesh sizes (20-40 μm) and controlling flow rates to achieve both high purity and scalability. The cross-flow mechanism with tangential flow prevents clogging while maintaining filtration efficiency, enabling large-scale production without sacrificing purity.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention employs hydraulic principles through cross-flow filtration where fluid flows tangentially across the filter surface, creating a shear force that prevents particle accumulation and clogging. This hydraulic approach enables continuous filtration at large scales while maintaining high purification efficiency.

Inventive Principle:
Principle #29Pneumatics and hydraulics

2Productivity

If cross-flow filtration is used with mesh size of 20 to 40 μm, then scalable production is enabled, but filter clogging occurs

Engineering Contradiction:
Improveproduction scalabilityVSAvoidfilter clogging
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The invention makes the filtration system dynamic by implementing cross-flow where the fluid continuously moves tangentially across the filter surface rather than flowing straight through. This dynamic flow pattern prevents static accumulation of particles that cause clogging, enabling sustained scalable production.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The invention applies mechanical vibration to the filter surface to prevent particle accumulation and clogging. The vibration creates oscillating flow patterns that dislodge particles from the filter surface, maintaining filtration efficiency during scalable production operations.

Inventive Principle:
Principle #18Mechanical vibration

3Device complexity

If traditional filtration methods are used, then simple equipment is required, but nanowire length control is poor

Engineering Contradiction:
Improvefiltration equipment simplicityVSAvoidnanowire length control
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

The invention changes the filtration parameters by using cross-flow filtration with specific mesh sizes (20-40 μm) and controlling flow rates to achieve both high purity and scalability. The cross-flow mechanism with tangential flow prevents clogging while maintaining filtration efficiency, enabling large-scale production without sacrificing purity.

Inventive Principle:
Principle #35Parameter changes

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

This approach enables the scalable production of high-purity silver nanowires with controlled lengths, resulting in transparent conductive films with beneficial haze, transmission, and sheet resistance characteristics, suitable for flexible and bendable substrates.

Implementation Method 1

filtering the nanowires in solution by cross-flow filtration, wherein the step of filtering the nanowires in solution by cross-flow filtration includes the step of passing the solution comprising nanowires through a cross-flow filter

Methodology Applied
Scientific EffectFiltration: Filter (physical)

Implementation Method 2

incorporating a vibration system to prevent clogging

Methodology Applied
Scientific EffectVibration: Vibration

Data Source

PatentEP3386660B1Methods of purifying nanostructures
Publication Date: 2023.07.19 QUANTUM CHEMICAL TECHNOLOGIES SPORE PTE LTD
  • EP3386660B1 patent drawingFigure 1
  • EP3386660B1 patent drawingFigure 2
  • EP3386660B1 patent drawingFigure 3

AI summary

The present invention relates to methods of purifying nanostructures. The nanostructures may be silver nanowires.