Thiol-Based Binder for Metal-Silicone Interface in Stretchable Electronics
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Solution Overview
Problem
The use of silicone or polydimethylsiloxane (PDMS) materials as substrates for stretchable and flexible electronics is challenging due to poor wetting and adhesion between deposited electronically conductive metal traces/interconnects and the inert/hydrophobic silicone surface.
Innovation Solution
The modification of the metal ink-silicone interface by functionalizing the surface of noble metal nanoparticles or nanowires and the silicone substrates using small molecule binders for thiol-noble metal bonding, specifically utilizing compounds like 3-mercapto-1-propanesulfonic acid and polydimethylsiloxane (PDMS).
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If silicone substrates are used for stretchable electronics, then biocompatibility and softness are improved, but adhesion of metal traces deteriorates
Solution Approach 1:
The patent introduces a small molecule binder as an intermediary substance that bridges the metal nanoparticles and silicone substrate. This binder contains both a thiol group that binds to metal and a silane group that bonds to the silicone substrate, thereby mediating the interface between the two incompatible materials and enabling strong adhesion without compromising the biocompatibility of the silicone.
Solution Approach 2:
The invention creates a composite interface system combining metal nanoparticles, small molecule binder, and silicone polymer. This composite structure integrates the beneficial properties of each component: the metal provides conductivity, the binder provides bonding functionality, and the silicone provides biocompatibility and flexibility, achieving both adhesion and biocompatibility simultaneously.
2Ease of operation
If silicone substrates are used for stretchable electronics, then softness and flexibility are improved, but wetting of metal inks deteriorates
Solution Approach 1:
The small molecule binder acts as a wetting intermediary by providing chemical groups that interact with both the metal ink and the silicone surface. The thiol group facilitates metal nanoparticle aggregation while the silane group creates chemical bonding sites on the silicone, thereby improving wetting and spreading of the metal ink without affecting the softness of the substrate.
Solution Approach 2:
The invention changes the surface chemistry parameters of the silicone substrate by introducing functional groups (thiol and silane) through the small molecule binder. This modifies the surface energy and chemical composition to enhance wetting properties while maintaining the bulk softness and flexibility of the silicone material.
3Reliability
If noble metal nanoparticles are used for conductive traces, then electrical conductivity is improved, but adhesion to silicone deteriorates
Solution Approach 1:
The small molecule binder serves as a dual-function intermediary: its thiol group forms strong bonds with the noble metal nanoparticles to maintain electrical conductivity, while its silane group creates robust chemical adhesion to the silicone substrate. This mediator enables both conductivity and adhesion to coexist.
Solution Approach 2:
The patent applies preliminary action by pre-functionalizing the metal nanoparticles with the small molecule binder before deposition onto the silicone substrate. This preliminary bonding ensures that the metal particles are already prepared to adhere strongly to the substrate, preventing detachment and maintaining conductivity from the outset.
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 significantly improves the wetting and adhesion of noble metal inks to silicone substrates, enhancing the performance and reliability of stretchable and flexible electronics.
Implementation Method 1
functionalizing the surface of noble metal nanoparticles (NPs) or nanowires (NWs), such as silver (Ag) NPs or NWs, and/or the surface of silicone substrates, using small molecule binders for thiol-noble metal bonding
Implementation Method 2
the metal ink-silicone interface is modified by functionalizing the surface of noble metal nanoparticles (NPs) or nanowires (NWs), such as silver (Ag) NPs or NWs, and/or the surface of silicone substrates
Implementation Method 3
compositions and methods for wetting and adhering noble metal inks to silicone substrates
Data Source
AI summary
Described herein are compositions and methods for wetting and adhering noble metal inks to silicone substrates. The metal ink-silicone interface is modified by functionalizing the surface of noble metal nanoparticles (NPs) or nanowires (NWs), and/or the surface of silicone substrates, with a small molecule binder for thiol-noble metal bonding.