Facile Multiscale Patterning by Creep-Assisted Sequential Imprinting and Fuel Cell Application.
The capability of fabricating multiscale structures with desired morphology and incorporating them into engineering applications is key to realizing technological breakthroughs by employing the benefits from both microscale and nanoscale morphology simultaneously. Here, we developed a facile patterning method to fabricate multiscale hierarchical structures by a novel approach called creep-assisted sequential imprinting. In this work, nanopatterning was first carried out by thermal imprint lithography above the glass transition temperature (Tg) of a polymer film, and then followed by creep-assisted imprinting with micropatterns based on the mechanical deformation of the polymer film under the relatively long-term exposure to mechanical stress at temperatures below the Tg of the polymer. The fabricated multiscale arrays exhibited excellent pattern uniformity over large areas. To demonstrate the usage of multiscale architectures, we incorporated the multiscale Nafion films into polymer electrolyte membrane fuel cell, and this device showed more than 10% higher performance than the conventional one. The enhancement was attributed to the decrease in mass transport resistance because of unique cone-shape morphology by creep-recovery effects and the increase in interfacial surface area between Nafion film and electrocatalyst layer.
Segeun
S
Jang
Center for Nanoparticle Research, Institute for Basic Science (IBS) , Seoul 151-742, Republic of Korea.
Minhyoung
M
Kim
Center for Nanoparticle Research, Institute for Basic Science (IBS) , Seoul 151-742, Republic of Korea.|Fuel Cell Research Center, Korea Institute of Science and Technology (KIST) , Seoul 136-791, Korea.
Yun Sik
YS
Kang
Yong Whan
YW
Choi
Department of Mechanical Engineering, Incheon National University , Incheon 406-772, Republic of Korea.
Sang Moon
SM
Kim
Center for Nanoparticle Research, Institute for Basic Science (IBS) , Seoul 151-742, Republic of Korea.
Yung-Eun
YE
Sung
Mansoo
M
Choi
Nafion; creep behavior; multiscale patterning; polymer electrolyte membrane fuel cells; thermal imprinting