Molecular ink and method for printing resistive film coatings
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Solution Overview
Problem
Current conductive inks used in flexible electronics, such as e-textiles, face challenges with conductivity when subjected to bending and stretching, and are not suitable for high-temperature curing processes, leading to reduced performance and longevity.
Innovation Solution
Development of molecular inks comprising particle-free metal complexes and conductive filler materials, which conformally coat flexible substrates, including textiles, to form continuous conductive patterns with improved conductivity and resistance to mechanical stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conductive inks are used to print on flexible substrates, then conductive paths can be formed, but conductivity is reduced when the substrate is bent or stretched
Solution Approach 1:
The patent uses composite materials consisting of conductive metal nanoparticles embedded within a flexible polymer matrix. This composite structure allows the material to maintain electrical conductivity while accommodating bending and stretching deformations, as the polymer matrix provides mechanical flexibility while the conductive particles maintain electrical pathways.
Solution Approach 2:
The patent employs thin film coatings of conductive ink that conformally coat the flexible substrate. The thin film structure allows the conductive layer to flex and stretch with the substrate without cracking or losing conductivity, as the thin geometry accommodates deformations more easily than bulk materials.
2Reliability
If high temperature sintering is used to cure conductive inks, then conductive paths are formed, but the substrate may melt or deform
Solution Approach 1:
The patent changes the curing parameters by using low-temperature processing methods instead of high-temperature sintering. The conductive ink formulation allows curing at temperatures below 100°C through alternative mechanisms such as solvent evaporation and polymer crosslinking, avoiding substrate damage while still forming conductive pathways.
Solution Approach 2:
The patent replaces the thermal sintering mechanism with alternative curing mechanisms such as photopolymerization or chemical crosslinking. This substitution allows the conductive ink to form conductive paths through chemical reactions rather than high-temperature melting and bonding, thereby protecting temperature-sensitive substrates.
3Reliability
If conductive inks are printed on textiles, then flexible electronics can be created, but the conductivity deteriorates after wear and wash cycles
Solution Approach 1:
The patent applies preliminary treatment to the textile substrate before printing the conductive ink, such as plasma treatment or chemical priming. This preliminary action enhances the adhesion of the conductive ink to the textile fibers, ensuring that the conductive pathways remain intact during subsequent wear and wash cycles.
Solution Approach 2:
The patent introduces an intermediary layer or binding agent between the conductive ink and the textile substrate. This intermediary material acts as an adhesive that strongly bonds to both the ink particles and the textile fibers, preventing detachment and maintaining conductivity during mechanical stress and washing.
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 molecular inks provide flexible electronic elements with enhanced conductivity and durability, maintaining performance through multiple wear and wash cycles, and can be easily integrated into existing textile manufacturing processes.
Implementation Method 1
the molecular inks conformally coat the substrate, and in particular for textile substrates, fibers of the substrate
Implementation Method 2
After curing, the molecular inks form continuous conductive or resistive patterns or coatings that comprise metal nanoparticles
Data Source
AI summary
Described herein are molecular inks, methods for printing the molecular inks on flexible substrates, and methods for forming printed electronic elements, such as resistive heaters, force sensors, motion sensors, and devices that include these elements, such as force responsive conductive heaters. The methods include printing a molecular ink on a flexible substrate that is heated to 30° C. to 90° C. before and/or during the printing process and curing the substrate to produce a conductive pattern thereon. The molecular inks generally include a particle-fee metal-complex composition formulated from at least one metal complex and a solvent, and optionally, a conductive filler material, and/or surfactant.