Jay R. Sayre

Seals and Sealants in PEM Fuel Cell Environments: Material, Design, and Durability Challenges

Fuel cells have significant potential to improve energy utilization efficiency, but remain quite expensive due to the cost of key components, including the membrane of PEM fuel cells, the catalyst, and the bipolar plates. Due to the cost and significance of these items, extensive research has been devoted to reducing cost and improving the quality and performance of these components. By contrast, seals, sealants, and adhesives play a more mundane role in the overall performance of fuel cells, and yet the failure of these materials can lead to reduced system efficiency, system failure, or even safety concerns. Less attention has been given to the performance and durability of these products, yet as improvements in other fuel cell components are made, these seals are becoming a more critical link in the long term performance of fuel cells. This review paper highlights the importance and background of fuel cell seals; discusses the chemical, thermal, and mechanical environments to which fuel cell seals are subjected; and suggests design and testing protocol improvements that may lead to improved fuel cell system performance.Copyright

Electroactive polymer (EAP) mobility device

Ionomeric polymer-metal composites (IPMCs) are a class of electroactive polymers (EAPs) that silently bend and exert force in response to an applied voltage. In this work, a unique design is presented where IPMCs are used to accomplish rotary motion. A novel feature is that EAP actuation is used in conjunction with gravity to cause rotation. This idea could be used to create a self-driven roller device. Such a roller could resemble a wheel with a circular or cylindrical geometry, or a sphere capable of rolling in all directions. Numerical simulations were performed that show a two dimensional roller device can accomplish rolling motion as a result of IPMC actuation. Experimental data on the deformation performance of fabricated IPMCs was used to drive the numerical simulations of the device. A possible application of this mechanism could be a mobility device on the centimeter scale that can transport a payload silently to a target destination.