Printable Stretchable Conductive Ink Using Capillary Suspension Networks
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Solution Overview
Problem
Existing stretchable conductive inks face a trade-off between electrical conductivity and mechanical stretchability, with few methods simultaneously achieving high conductivity, printability, and deformability, and most struggle with cyclic durability and large-scale production compatibility.
Innovation Solution
A highly conductive and printable ink is developed using a capillary suspension phenomenon with hydrophobic silver particles dispersed in a cross-linkable polydimethylsiloxane polymer matrix, incorporating an immiscible secondary fluid phase that self-assembles into a percolating network, allowing for high stretchability and cyclic durability through standard printing techniques.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high volume fraction of conductive particles is embedded in flexible polymer to provide high conductivity, then electrical conductivity is improved, but deformability and stretchability are reduced
Solution Approach 1:
The conductive particles are segmented into hierarchical structures with primary particles (5-10 μm) and secondary aggregates (50-200 μm), allowing the conductive network to maintain connectivity while accommodating deformation. The segmented structure enables particles to rearrange during stretching without complete network failure.
Solution Approach 2:
The invention uses a composite material system combining hydrophobic conductive particles (silver, aluminum, or copper) with a cross-linkable polydimethylsiloxane polymer matrix. This composite structure provides both high electrical conductivity through the particle network and high stretchability through the elastomeric polymer matrix, achieving over 1000% elongation while maintaining conductivity.
2Adaptability or versatility
If plasticizer is added to conducting polymer to guarantee good stretchability, then mechanical flexibility is improved, but electrical conductivity deteriorates
Solution Approach 1:
The polydimethylsiloxane polymer matrix acts as an intermediary between the hydrophobic conductive particles and the environment, providing mechanical flexibility and stretchability without interfering with the electrical conductivity of the particle network. The matrix allows particle rearrangement during deformation while maintaining network connectivity.
Solution Approach 2:
The invention changes the parameter of particle hydrophobicity by selecting particles with contact angle >90°, which fundamentally alters how particles interact with the polymer matrix and with each other. This parameter change enables the formation of a stable, conductive network that maintains connectivity under deformation, achieving both high stretchability and conductivity without requiring plasticizers.
3Ease of manufacture
If conventional conductive inks are used for soft electronics, then manufacturing process is simple, but cyclic durability under large deformation is insufficient
Solution Approach 1:
The conductive particle network is designed to be dynamic rather than static, allowing particles to rearrange, rotate, and reconfigure during cyclic deformation. The hydrophobic particles maintain network connectivity through adaptive rearrangement, enabling the material to withstand over 1000 cyclic stretches at 100% strain while maintaining conductivity.
Solution Approach 2:
The invention changes the surface property parameter of conductive particles by selecting hydrophobic materials with contact angle >90°, which fundamentally alters the particle-polymer and particle-particle interactions. This parameter change enables the formation of a stable, flexible network that maintains connectivity under cyclic deformation, achieving both ease of manufacture and superior cyclic durability.
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 ink achieves unprecedented stretchability up to 1000% with maintained conductivity and superior cyclic durability, exceeding current standards, and is compatible with large-scale production and various printing methods.
Implementation Method 1
A highly conductive and printable ink is developed using a capillary suspension phenomenon with hydrophobic silver particles dispersed in a cross-linkable polydimethylsiloxane polymer matrix
Implementation Method 2
hydrophobic silver particles dispersed in a cross-linkable polydimethylsiloxane polymer matrix
Implementation Method 3
cross-linkable polydimethylsiloxane polymer matrix
Data Source
AI summary
The present invention relates to highly conductive, printable inks for highly stretchable soft electronics, a process for their manufacture as well as a process for producing highly stretchable soft electronics.