Erika Rebrosova | Sun Chemical: How can co-printing silver and carbon inks slash hysteresis in stretchable circuits?

Can a screen-printable ink eliminate the need for thermoplastic polyurethane (TPU) substrates in stretchable electronics?

Evaluating stretchable electronics often requires thick, rigid thermoplastic polyurethane (TPU) substrates that limit device drapability. Sun Chemical addresses this limitation with a water-based, screen-printable encapsulant and insulator that can serve as a standalone carrier. This material allows direct patterning of multi-layer encapsulated structures without the need for traditional TPU backing.

By utilizing a cold release PET liner, manufacturers can print the entire circuit and peel it off to yield an ultra-thin, highly draped, and soft device. This transfer-tape style formulation significantly reduces final component thickness while retaining robust insulation.

Understanding the formulation chemistry of these elastic silver and carbon systems is key to successfully integrating printed electronics into space-constrained surfaces. This approach opens up new design freedoms for soft surfaces in automotive and medical applications.

In this short video, you can learn:
* How water-based insulators act as standalone carriers for multi-layer stretchable circuits.
* The processing steps for using cold release liners and tape transfer structures to minimize device thickness.
* The key differences between elastic silver and carbon inks regarding stretchability and crossover insulation.

📋 **Clip Abstract** Sun Chemical introduces its stretchable material portfolio, emphasizing a water-based screen-printable encapsulant that enables ultra-thin, standalone devices. By shifting from TPU substrates to cold release tape transfers, designers can achieve higher drapability and thinner profiles for integrated electronics.

How do the material choices for working electrodes impact the performance and application of electrochemical biosensors?

The working electrode in a three-electrode system (working, counter, and reference) is crucial for measuring changes in electrical signals resulting from chemical reactions. These electrodes are often functionalized to attract specific analyte molecules. Sun Chemical offers various materials for each electrode type, with carbon, gold, and platinum being the primary options for working electrodes.

Carbon electrodes are the lowest cost option and are suitable for generic molecule detection, particularly in enzymatic reactions. However, with proper functionalization, carbon can be used for other purposes. Gold electrodes are best suited for immunoassays, while platinum electrodes are ideal for DNA-based assays and direct peroxide detection.

The choice of material depends on the specific application and the target analyte. Sun Chemical provides inks based on carbon (including mediated carbons), gold, and platinum, catering to diverse biosensing needs. The availability of both low-temperature and high-temperature curing options further expands the applicability of these materials to different substrates and manufacturing processes.

In this short video, you can learn:
* The role of the working electrode in electrochemical biosensors.
* Material options for working electrodes: carbon, gold, and platinum.
* Application-specific suitability of each material type.

📋 **Clip Abstract** This segment details the function of the working electrode in electrochemical biosensors and explains how different materials like carbon, gold, and platinum cater to specific applications such as enzymatic reactions, immunoassays, and DNA-based assays. The clip also mentions the availability of low and high-temperature curing options for these materials.
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Why does the electrical resistance of printed stretchable inks deviate from ideal linear physics at higher strains?

Stretching a printed conductor causes its length to increase and its cross-sectional area to decrease, theoretically predicting a linear rise in resistance. In practice, however, printed polymer thick film inks exhibit complex non-linear behaviors due to dynamic changes in particle-to-particle contact. As the ink is strained, conductive pathways can either consolidate or break apart, disrupting ideal dimensional calculations.

At strains exceeding 20% to 25%, micro-cracking within the polymer binder matrix typically triggers a sharp, exponential increase in resistivity. Designing within the initial linear elastic zone is critical to ensuring predictable electrical performance during operation.

Analyzing the transition point where micro-fracturing begins allows material scientists to optimize binder elasticities for specific strain profiles. This distinction is vital for maintaining sensor calibration and heating uniformity in dynamic, high-strain applications.

In this short video, you can learn:
* The mathematical and physical relationships governing electrical resistance changes under mechanical strain.
* Why particle-to-particle contact dynamics cause deviations from theoretical linear resistance curves.
* How to identify the onset of micro-cracks in conductive silver and carbon inks during elongation.

📋 **Clip Abstract** This clip breaks down the physics of resistivity versus strain in stretchable silver and carbon inks. It highlights how dimensional changes, particle contacts, and the onset of micro-cracking govern performance limitations beyond 20% elongation.