In the present research, we have studied the influence of Ag additives on wettability, adhesion, oxidation, viscosity and modulus of liquid metal on two alloys – Liquid Metal 1 (“LM1”) (62.5Ga, 21.5In, 13Sn) and Liquid Metal 2 (“LM2”) (78.6Ga, 21.4In)– to develop new thermal interface materials for IC modules such as CPU and GPU in PC and game stations. In this study, liquid metals were first mixed with Ag powders of up to 1.5wt%, followed by treatment with 30wt% NaOH aqueous solution to remove the oxide in the liquid metal, to prepare liquid metal/Ag composites. Wettability and adhesion have been studied on bare Cu, and Ni/Au surface finish Cu. Contact angle of liquid metal with and without Ag powders was measured to evaluate wettability of liquid metal on bare Cu and Ni/Au Cu. Adhesion of the liquid metals with and without Ag additive on bare Cu and Ni/Au Cu were evaluated by temperature cycling test with a profile of -40oC to 125oC, dwell time of 20min at low and high temperature. Oxidation of the liquid metals on bare Cu and Ni/Au Cu substrate was monitored over time at ambient atmosphere and during temperature cycling test, followed by characterizing cross-section morphology with SEM. To investigate effect of Ag powders on viscosity, the viscosity was measured using a parallel plate viscometer. Thermal properties and performance of the prepared composite in this research will be evaluated by measurement of thermal resistance and conductivity, respectively.

Keyword: Liquid metal, 51E, 300E, wettability, oxidation, viscosity and modulus.

Light weight, conformal and portable standalone power solutions are becoming increasingly important for powering wearable electronics including fabric embedded sensors, to monitor the physiological and physical status of military personnel and civilians. Textile-based power-harvesting sources offer the advantage of conformability, light weight, drapability and breathability. We present the fabrication of Organic Photovoltaic (OPV) wires/fibers followed by the integration of the OPV into an electronic textile. A meniscus coating process is employed to fabricate a fiber-based OPV. Polished stainless-steelwire is used as a primary electrode that is coated with a titanium dioxide electron transport layer, followed by a coating of bulk-heterojunction Poly(3-hexylthiophene): phenyl-C61/71-butyric acid methyl ester (P3HT:PC61/71BM) active layer. A mixture comprising of a poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT: PSS) dispersion blended in a cross-linkable reactive diluent serves as the hole transport layer. A silver-plated copper wire serves as the secondary counter-electrode and is wrapped around the primary wire. The fiber device is then encapsulated in a UV-curable encapsulant that provides long-term stability by reducing the ingress of oxygen and water vapor. Performance and stability of these e-textiles are evaluated by characterizing the current- voltage (I-V) performance of the OPV fibers woven into a fabric. The appropriate selection of materials and the optimization of the coating parameters will enable the enhancement of power conversion efficiency (PCE) and stability of these power harvesting textiles for standalone, power.

Wearable devices for biomedical applications have become more popular due to the increasing demand on health monitoring for both consumer and medical fields. In this work, we describe a novel wireless wearable ElectroMyograph (EMG) acquisition and analysis system which employs reduced graphene oxide (rGO) coated Nylon/Polyester fabric sensors. The usability of graphene sensors was examined by comparing biceps EMG signals obtained from the graphene sensors to that from the standard Ag/AgCl sensors. Calf muscle EMG signals on both legs are measured to confirm the usability, the multi-sensor acquisition ability of the system. The measurement results indicate that graphene-based smart fabrics can be used as a viable alternative to non-reusable Ag/AgCl electrodes for high-quality EMG monitoring. The proposed EMG data acquisition and analysis device is small, lightweight providing a smart clothes platform for convenient health tracking.

Index Terms: ElectroMyography, reduced graphene oxide, e-Textiles, health monitoring, wearable

SINTEC is the project name for a Liquid metal alloy technology with the goal of creating flexible and stretchable electronics.  These stretchable electronics are applicable to wearable sensors that collect motion data of humans.   The stretching allows direct application of wearable electronics to very dynamic parts of the body.  Liquid metal alloy can be needle deposited.  

Textile-based touch sensing offers a novel solution towards creating flexible and robust tactile interfaces that fit within an existing manufacturing ecosystem.  Current fabric-based touch sensors can measure distributed and nuanced touch while maintaining textile qualities such as stretching and folding.  Recent work as described the development of a single-wire capacitive touch sensing system that consists of a textile interface and external sensing hardware that transmit recorded data to a trained neural network.  The sensing method localizes touch along a continuous conductor using a current differential measured at either endpoint.  The requisite touch sensing circuit is fully compatible with digital weft knitting, and its layout can be configured in a a variety of pathways to create complete planar textile interfaces. Each interface requires only two connections to external sensing hardware, which allows both the hardware to be reused between interfaces and the data transmitted to the network to have a similar dimension.  

Previous work focused on identifying touch location at defined points on a fabric interface through training a recognition system using labeled data.  We extend this work towards gesture recognition by using a generated intermediate model to decouple the estimated linear touch location and capacitance from the measured data.  The intermediate model forms a manifold of the normalized linear touch location and capacitance within the space of measured data points.  A measured data point, acting as a particle, is tracked through the manifold and decoupled to a unique touch location and capacitance. The decoupled linear touch location is mapped to a planar model of the textile interface, which is generated from a user-defined image of the interface.  the use of digital modeling tools creates a closed-loop interface design process which allows designers to construct a visual representation of the fabric circuit and predict its sensing performance. 

Keywords: Functional Fabrics, e-Textiles, Capacitive Sensing, Signal Processing

The research presented in this slide show utilizes E-Textiles. 

The applications include:

• Physiological Status Monitoring
• Cognitive Status Monitoring
• Performance/State Optimization (Intervention)

The fabrics contain sensors capable of monitoring human conditions.  This is specifically for military use.  

The DoD conducted a survey of PCB companies and the effects of COVID19.  The survey results showed that:

• Some U.S PrCB manufacturing facilities were significantly impacted by the pandemic
• Revenues from U.S Military work and healthcare industry were generally higher than last year so firms that serve thee sectors were more likely to have stable revenues during the pandemic. 
• U.S. PrCB manufacturing facilities have a need for assistance, in the form of grants and capacity building, to meet DOD;s CMMC requirements.
• DoD and industry could collaborate more closely to better understand and resolve ongoing supply chain disruptions, which were exacerbated by the pandemic
• It is important to explore economic incentives for encouraging investments in advanced technology, business reconfigurations, and other capital investments. 

Indiana Integrated Circuits has developed "Quilted" modular PCBs.  They consist of multiple small "boardlets" with traces or pads on rough edges of the boards.  These rough edges fit together with other boards like a jigsaw puzzle.  This type of in board encoding ensures high security from tampering.  It also allows for the continued miniaturization and standardization of common circuit types. Components can also have shorter traces between their leads/ solder ball.  Modularization of PCB technology also follows RECORD (Randomized Encoding of COmbinational Logic for Resistance to Data leakage) to increase HW (Hardware) security.

The Dod Executive Agent For Printed Circuit Board and Interconnect Technology (PrCB EA) has a vested interest in the state of the electronics industrial base and its ability to sustain and improve national defense systems.  By using a two-year cycle, the PrCB EA creates both a report and a supplementary roadmap to illuminate the state of the electronics industrial base and consider its future. 

The PrCB EA Report considers the following: 1) What are the current supply chain risks within the domestic and global printed circuit board (PrCB) industrial base? 2) Are the suppliers, manufacturers, and resources within the supply chains of the PrCB industrial base trustworthy? 3) Does the United States have access to the capability and capacity for manufacturing PrCBs, interconnect technology, and PrCB assemblies (PrCBAs) Needed to sustain the technological superiority over its adversaries?

The supplementary PrCB EA roadmap takes the greatest concerns from the PrCB EA Report and explores how, if neglected, these risks, and issues might devolve in the coming two, five and ten years. After outlining these potentials, The PrCB EA Roadmap considers how the DoD might address these concerns in order to protect domestic capability and capacity and sustain national defense systems.  

In the 2019 PrCB EA Report and upcoming 2020 PrCB EA Roadmap, the PRCB EA Explores the status of trust and qualification for manufacturers, the state of the art for PrCB And PrCBA manufacturing, the US PrCB supply chain diversity, the continued evolution of solder compositions, the U.S. reliance on foreign sources for materials, potential environmental restrictions on hazardous substances, and advances in PrCBA manufacturing technology.  

The PrCB EA believes the 2019 PrCB EA Report and upcoming 2020 PrCB EA Roadmap provide valuable information on domestic capability and capacity to the Dod acquisition and sustainment communities. This presentation will highlight the recommendations within these joint documents and how they will help ensure that the United States continues to have a viable and secure PrCB supply chain, the means to manufacture reliable PrCBs, interconnect technology, and PrCBAs, and the ability to sustain technological superiority over its adversaries for decades to come.