Anisotropic Conductive Paper via Electric Field Alignment
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Solution Overview
Problem
Existing methods for creating conductive paper require high fractions of conductive fillers, which are problematic, and long conductive fibers are difficult to disperse effectively, limiting their application in reducing electromagnetic interference.
Innovation Solution
A method involving a cellulose dispersion treated with an electric field to align conductive particles, reducing the need for high filler concentrations and enabling anisotropic electric conductivity, where conductive pathways are formed parallel to the electric field, allowing for directional conductivity at lower particle loads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high fractions of conductive fillers are used to achieve sufficient conductivity, then electrical conductivity is improved, but the paper becomes stiffer and more expensive
Solution Approach 1:
The patent changes the spatial distribution parameter of conductive particles from random to aligned configuration. By applying an electric field during processing, particles are oriented to form conductive pathways, achieving sufficient conductivity at lower filler fractions (below percolation threshold) compared to random distributions that require high filler content
Solution Approach 2:
The patent creates localized conductive pathways through particle alignment rather than uniform distribution. The electric field induces regions of high particle concentration along field lines, forming conductive channels in specific directions while maintaining lower overall filler content and preserving paper flexibility in non-conductive regions
2Object-affected harmful factors
If long conductive fibers are used to reduce electromagnetic interference, then EMI shielding effectiveness is improved, but dispersion becomes difficult
Solution Approach 1:
The patent replaces mechanical dispersion methods with an electric field-based alignment approach. Instead of relying on mechanical mixing to disperse long fibers (which creates aggregation problems), an electric field is applied to induce dipole moments in the fibers, causing them to align and disperse uniformly along field lines without mechanical agitation
Solution Approach 2:
The patent changes the physical state parameter by applying an electric field that induces dipole moments in conductive particles and fibers. This electromagnetic parameter change enables long fibers to align and disperse uniformly in the matrix without the aggregation problems associated with mechanical mixing of long conductive elements
3Reliability
If high fractions of conductive particles are used to ensure conductivity, then electrical conductivity is improved, but the cost and weight increase
Solution Approach 1:
The patent changes the spatial arrangement parameter of conductive particles from random to aligned configuration through electric field application. This creates efficient conductive pathways that achieve the required conductivity at significantly lower filler fractions, reducing both weight and cost compared to random distributions requiring high filler content
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 achieves anisotropic electric conductivity with significantly lower filler fractions, enhancing applications such as electromagnetic interference shielding and energy storage devices while maintaining paper properties like flexibility and reducing stiffness.
Implementation Method 1
electric field alignment of conductive particles mixed in this fluid
Implementation Method 2
electric field alignment of conductive particles mixed in this fluid
Data Source
Figure 1~3
Figure 4~5
AI summary
A method for treating a paper to provide at least a part of it with anisotropic electric conductivity, by i) applying to the paper a dispersion comprising a non-aqueous, liquid dispersing agent and conductive particles, ii) applying an electric field over at least part of the paper, so that a number of the conductive particles are aligned with the field, thus creating conductive pathways, and wholly or partially eliminating the dispersing agent and allowing the paper to dry thereby stabilizing and preserving the conductive pathways in the paper as well as paper so produced. The paper may alternatively be prepared from a cellulose dispersion comprising conductive particles and subjecting the dispersion for similar aligning of the conductive particles.