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Published May 26, 2005 | public
Journal Article

Nanophase Segregation and Water Dynamics in the Dendrion Diblock Copolymer Formed from the Fréchet Polyaryl Ethereal Dendrimer and Linear PTFE

Abstract

We propose a new material consisting of a dendrion copolymer formed from (a) a water-soluble dendritic polymer and (b) a hydrophobic backbone. Using molecular dynamics simulations techniques, we determine the structure and dynamics of the dendrion formed by second-generation Fréchet polyaryl ethereal dendrimer as the hydrophilic component and linear polytetrafluoroethylene (PTFE) as the hydrophobic polymer, with 5 and 10 wt % of water. We find that this material produces a well-developed nanoscale structure in which water forms a continuous nanophase, making this new family of compounds promising candidates for applications in fuel cell membranes. We find that the water molecules are incorporated into the dendrimer block of the copolymer to form a nanophase-segregated structure. The well-developed nanophase-segregated structures rendered by this material have characteristic dimensions of segregation (∼30 Å) and dendrimer conformational properties that are independent of water content. Calculations of water dynamics and proton transport in these nanophase-segregated structures indicate that the dendrion copolymer membrane with 10 wt % of water content has a water structure and transport properties equivalent to that of the hydrated Nafion membrane with 20 wt % of water content.

Additional Information

© 2005 American Chemical Society. Received: January 7, 2005; In Final Form: March 31, 2005. We thank Dr. Gerald Voecks of General Motors for many helpful discussions. The facilities of the Materials and Process Simulation Center used for these studies are supported by DURIP-ARO, DURIP-ONR, IBM-SUR, and NSF (MRI), and other support for the MSC comes from MURI-ARO, MURI-ONR, DOE, ONR, NSF-CSEM, NIH, General Motors, Chevron-Texaco, Seiko-Epson, Beckman Institute, and Asahi Kasei.

Additional details

Created:
August 19, 2023
Modified:
October 25, 2023