Conductive Porous Composite Coating for Stable 3D Piezoresistive Sensing
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Solution Overview
Problem
Conventional piezoresistive devices face limitations in durability, sensing sensitivity, and shape stability due to deformation of porous base materials during coating and drying, which affects the adhesion stability of conductive layers and restricts their application on curved surfaces and in multiple directions.
Innovation Solution
A method involving immersion of a porous base material in a conductive coating solution with a solvent having a lower surface tension than the base material, followed by controlled drying to form a conductive coating layer, ensuring even coating and preventing shape deformation, thereby enhancing adhesion stability and flexibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a porous base material is immersed in a dispersion solution and dried, then the conductive material is coated on the base material, but the porous body deforms due to swelling and twisting during drying, reducing manufacturing precision and adhesion stability
Solution Approach 1:
The patent changes the surface tension parameter of the coating solution by selecting specific solvents (ethyl acetate, butyl acetate, toluene, xylene) with surface tension values between 20-35 mN/m, which is lower than the porous base material's surface tension. This parameter change allows the solution to coat evenly without causing swelling deformation during drying, maintaining both shape stability and coating adhesion
Solution Approach 2:
The patent introduces a specifically formulated coating solution as an intermediary medium that contains conductive material dispersed in solvents with controlled surface tension. This intermediary enables uniform coating while preventing direct harmful interaction between the porous base material and the drying process that would cause deformation and adhesion failure
2Measurement precision
If a large amount of conductive material is included in the composite, then sensing sensitivity is improved, but the device exhibits lower conductive properties and higher resistance value
Solution Approach 1:
The patent optimizes the surface tension parameter of the coating solution to enable uniform distribution of conductive material at lower concentrations. By controlling the surface tension to be lower than the base material, the solution penetrates and coats evenly, achieving high sensing sensitivity with reduced conductive material content, thus maintaining good conductive properties
Solution Approach 2:
The patent replaces the mechanical mixing approach with a surface tension-based coating mechanism. Instead of relying on mechanical dispersion of conductive material in the composite, the invention uses surface tension differential to achieve uniform coating and distribution, enabling effective sensing with minimal conductive material
3Manufacturing precision
If the surface tension of the solvent is not lower than the porous base material, then the coating solution cannot be evenly coated, but if it is too low, the porous body deforms during drying
Solution Approach 1:
The patent precisely controls the surface tension parameter of the solvent within a specific range (20-35 mN/m), which is lower than the porous base material's surface tension but not excessively low. This optimized parameter change achieves even coating distribution while preventing swelling and deformation during the drying process
Solution Approach 2:
The patent applies partial wetting action by using a solvent with surface tension slightly lower than the base material. This partial action is sufficient to achieve uniform coating penetration without excessive wetting that would cause swelling and shape deformation during drying
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 improved adhesion stability, resistance change, and elastic recovery, enabling the use of conductive composites in 3D piezoresistive sensors that can sense pressure in multiple directions with high sensitivity and durability, suitable for various applications including curved surfaces.
Implementation Method 1
immersing a porous base material in a conductive coating solution
Implementation Method 2
drying the conductive coating solution on the porous base material to form a conductive coating layer
Implementation Method 3
The piezoresistive effect refers to a change in the electrical resistance value of a material due to external pressure or force
Data Source
AI summary
A method of preparing a conductive composite includes immersing a porous base material in a conductive coating solution, and drying the conductive coating solution on the porous base material to form a conductive coating layer on the porous base material. The conductive coating solution includes conductive particles and a solvent, and the surface tension of the solvent is lower than the surface tension of the porous base material by 8 mN/m or more, and a conductive composite is prepared therefrom.