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Tailoring of Interfacial Mechanical Shear Strength by Surface Chemical Modification of Silicon Microwires Embedded in Nafion Membranes

Gallant, Betar M. and Gu, X. Wendy and Chen, David Z. and Greer, Julia R. and Lewis, Nathan S. (2015) Tailoring of Interfacial Mechanical Shear Strength by Surface Chemical Modification of Silicon Microwires Embedded in Nafion Membranes. ACS Nano, 9 (5). pp. 5143-5153. ISSN 1936-0851 . http://resolver.caltech.edu/CaltechAUTHORS:20150429-103132238

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Abstract

The interfacial shear strength between Si microwires and a Nafion membrane has been tailored through surface functionalization of the Si. Acidic (−COOH-terminated) or basic (−NH_2-terminated) surface-bound functionality was introduced by hydrosilylation reactions to probe the interactions between the functionalized Si microwires and hydrophilic ionically charged sites in the Nafion polymeric side chains. Surfaces functionalized with SiO_x, Si–H, or Si–CH_3 were also synthesized and investigated. The interfacial shear strength between the functionalized Si microwire surfaces and the Nafion matrix was quantified by uniaxial wire pull-out experiments in an in situ nanomechanical instrument that allowed simultaneous collection of mechanical data and visualization of the deformation process. In this process, an axial load was applied to the custom-shaped top portions of individual wires until debonding occurred from the Nafion matrix. The shear strength obtained from the nanomechanical measurements correlated with the chemical bond strength and the functionalization density of the molecular layer, with values ranging from 7 MPa for Si–CH3 surfaces to ∼16–20 MPa for oxygen-containing surface functionalities. Hence surface chemical control can be used to influence the mechanical adhesion forces at a Si–Nafion interface.


Item Type:Article
Related URLs:
URLURL TypeDescription
http://dx.doi.org/10.1021/acsnano.5b00468DOIArticle
http://pubs.acs.org/doi/abs/10.1021/acsnano.5b00468PublisherArticle
http://pubs.acs.org/doi/suppl/10.1021/acsnano.5b00468PublisherSupporting Information
ORCID:
AuthorORCID
Greer, Julia R.0000-0002-9675-1508
Lewis, Nathan S.0000-0001-5245-0538
Additional Information:© 2015 American Chemical Society. Received for review January 21, 2015 and accepted April 14, 2015. Publication Date (Web): April 14, 2015. This research made use of the Shared Experimental Facilities supported by the Molecular Materials Research Center at the California Institute of Technology and of funds provided by the National Science Foundation (NSF) Center for Chemical Innovation: Solar Fuels (Grant CHE-1305124). B.M.G. acknowledges financial support from a Caltech Kavli Nanoscience Institute Prize Postdoctoral Fellowship.
Group:Kavli Nanoscience Institute
Funders:
Funding AgencyGrant Number
NSFCHE-1305124
Kavli Nanoscience InstituteUNSPECIFIED
Subject Keywords:Si microwires; in situ tension; nanomechanical; surface functionalization; Nafion
Record Number:CaltechAUTHORS:20150429-103132238
Persistent URL:http://resolver.caltech.edu/CaltechAUTHORS:20150429-103132238
Official Citation:Tailoring of Interfacial Mechanical Shear Strength by Surface Chemical Modification of Silicon Microwires Embedded in Nafion Membranes Betar M. Gallant, X. Wendy Gu, David Z. Chen, Julia R. Greer, and Nathan S. Lewis ACS Nano 2015 9 (5), 5143-5153 DOI: 10.1021/acsnano.5b00468
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:57086
Collection:CaltechAUTHORS
Deposited By: Tony Diaz
Deposited On:29 Apr 2015 17:40
Last Modified:25 Jun 2015 21:10

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