title: Investigation of the Interaction between Nafion Ionomer and Surface Functionalized Carbon Black Using Both Ultrasmall Angle X-ray Scattering and Cryo-TEM.
abstract: In making a catalyst ink, the interactions between Nafion ionomer and catalyst support are the key factors that directly affect both ionic conductivity and electronic conductivity of the catalyst layer in a membrane electrode assembly. One of the major aims of this investigation is to understand the behavior of the catalyst support, Vulcan XC-72 (XC-72) aggregates, in the existence of the Nafion ionomer in a catalyst ink to fill the knowledge gap of the interaction of these components. The dispersion of catalyst ink depends not only on the solvent but also on the interaction of Nafion and carbon particles in the ink. The interaction of Nafion ionomer particles and XC-72 catalyst aggregates in liquid media was studied using ultrasmall-angle X-ray scattering and cryogenic TEM techniques. Carbon black (XC-72) and functionalized carbon black systems were introduced to study the interaction behaviors. A multiple curve fitting was used to extract the particle size and size distribution from scattering data. The results suggest that the particle size and size distribution of each system changed significantly in Nafion + XC-72 system, Nafion + NH2-XC72 system, and Nafion + SO3H-XC-72 system, which indicates that an interaction among these components (i.e., ionomer particles and XC-72 aggregates) exists. The cryogenic TEM, which allows for the observation the size of particles in a liquid, was used to validate the scattering results and shows excellent agreement.
authors.affiliation: Department of Mechanical Engineering, Indiana University Purdue University Indianapolis (IUPUI) , Indianapolis, Indiana 46202, United States.|School of Mechanical Engineering, Purdue University , West Lafayette, Indiana 47097, United States.
authors.forename: Fan
authors.initials: F
authors.lastname: Yang
authors.affiliation: Department of Mechanical Engineering, Indiana University Purdue University Indianapolis (IUPUI) , Indianapolis, Indiana 46202, United States.
authors.forename: Le
authors.initials: L
authors.lastname: Xin
authors.affiliation: School of Materials Engineering, Purdue University , West Lafayette, Indiana 47907, United States.
authors.forename: Aytekin
authors.initials: A
authors.lastname: Uzunoglu
authors.affiliation: Department of Chemical and Biological Engineering, Biorenewable Research Laboratory, Iowa State University , Ames, Iowa 50011, United States.
authors.forename: Yang
authors.initials: Y
authors.lastname: Qiu
authors.affiliation: School of Materials Engineering, Purdue University , West Lafayette, Indiana 47907, United States.|Weldon School of Biomedical Engineering, Purdue University , West Lafayette, Indiana 47907, United States.
authors.forename: Lia
authors.initials: L
authors.lastname: Stanciu
authors.affiliation: X-ray Science Division, Argonne National Laboratory , Lemont, Illinois 60439, United States.
authors.forename: Jan
authors.initials: J
authors.lastname: Ilavsky
authors.affiliation: Department of Chemical and Biological Engineering, Biorenewable Research Laboratory, Iowa State University , Ames, Iowa 50011, United States.
authors.forename: Wenzhen
authors.initials: W
authors.lastname: Li
authors.affiliation: Department of Mechanical Engineering, Indiana University Purdue University Indianapolis (IUPUI) , Indianapolis, Indiana 46202, United States.
authors.forename: Jian
authors.identifier: http://orcid.org/0000-0002-9800-0206
authors.initials: J
authors.lastname: Xie
keywords: Nafion ionomer; Pt/C catalyst; USAXS; X-ray scattering; catalyst ink; cryo-TEM; dispersion; fuel cell