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Award Abstract #0512156
Role of Structure and Dynamics of Molecules at the Interface in Controlling Friction, Adhesion and Adhesion Hysteresis


NSF Org: DMR
Division of Materials Research
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Initial Amendment Date: May 24, 2005
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Latest Amendment Date: April 11, 2008
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Award Number: 0512156
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Award Instrument: Continuing grant
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Program Manager: Andrew J. Lovinger
DMR Division of Materials Research
MPS Directorate for Mathematical & Physical Sciences
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Start Date: June 1, 2005
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Expires: May 31, 2009 (Estimated)
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Awarded Amount to Date: $400000
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Investigator(s): Ali Dhinojwala alid@polymer.uakron.edu (Principal Investigator)
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Sponsor: University of Akron
302 Buchtel Common
Akron, OH 44325 330/972-7666
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NSF Program(s): POLYMERS
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Field Application(s): 0106000 Materials Research
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Program Reference Code(s): AMPP, 9161
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Program Element Code(s): 1773

ABSTRACT

We propose to combine surface sensitive infrared-visible sum frequency generation

spectroscopy (SFG) with insitu friction and adhesion measurements. The experiments

are motivated by results of Chaudhury and Brown using poly (dimethylsiloxane) (PDMS)

lenses and Israelachvili using surface force apparatus; where they find a relationship

between friction, adhesion hysteresis and mobility of the molecules at the interface.

However, there is no information on how different relaxation processes are at

polymer/solid or hidden interfaces in comparison to that in bulk. Recent experiments of

glass transition temperature of polymer thin films indicate that the relaxation at the air

interface can be several orders of magnitude faster than in the bulk. The relaxation

times of polymer chains are expected to be altered in contact with surfaces of different

surface energies. Furthermore, there is no direct information of the change in the

structure of molecules at moving or sliding interfaces. Understanding these properties is

crucial to understand friction. Recently, we demonstrated that SFG can be applied to

study the contact interface between an elastomeric PDMS lens and a polymer or solid

substrate. Here, we take advantage of this design to measure simultaneously the

changes in structure between two sliding surfaces, friction and adhesion. In addition, we

propose to measure the relaxation dynamics at interfaces using SFG to understand the

relationship between mobility and friction coefficient. As a Director of District 5, I have

been actively involved in organizing District 5 Science Day for students from K5-K12 for

the past five years. In addition to this outreach activity, this proposal offers research

opportunities to two high school students from a local high school to work during

summer in my laboratory under the supervision of graduate students. The research of

these high school projects can be submitted as a part of their science project for

competition in the Intel Science and Engineering Fair. This effort will be integrated with

the NSF-REU undergraduate program already existing at The University of Akron.

Broader Impact: Friction between two surfaces is of utmost importance in a variety of

technological and biological applications. The understanding and control of these

phenomena will have a tremendous impact in conserving and using precious energy

resources. The advances in this field are limited by the lack of understanding of the

structure and properties of molecules at the interface. This proposal provides a new

experimental method to probe molecular motion or deformation taking place at the

interface and studies its relationship to friction and adhesion. This will broadly impact

our design of surfaces, lubricants and micro or nano-actuators. The education and

outreach activities target local schools in District 5 to promote an interest in science by

encouraging students to undertake science projects and compete at district, state and

international level.


PUBLICATIONS PRODUCED AS A RESULT OF THIS RESEARCH

(Showing: 1 - 11 of 11).

Betul Yurdumakan, Gary P. Harp, Mesfin Tsige and Ali Dhinojwala.  "Template-Induced Enhanced Ordering under Confinement,"  Langmuir,  v.21,  2005,  p. 10316.

Betul Yurdumakan, Kumar Nanjundiah, and Ali Dhinojwala.  "Origin of Higher Friction for Elastomers Sliding on Glassy Polymers,"  Journal of Physical Chemistry C,  v.111,  2007,  p. 960.

Betul Yurdumakan, Nachiket Raravikar, Pulickel Ajayan and Ali Dhinojwala.  "Synthetic Gecko Foot-Hairs from Multiwalled Carbon Nanotubes,"  Chemical Communications,  2005,  p. 3799.

Gary P. Harp and Ali Dhinojwala.  "Direct Probe of Interfacial Structure during Mechanical Contact between Two Polymer Films Using Infrared Visible Sum Frequency Generation Spectroscopy,"  Journal of Adhesion,  v.81,  2005,  p. 371.

Gary P. Harp, Hasnain Rangwalla, Guifeng Li, Mohsen S. Yeganeh, and Ali Dhinojwala.  "Coupling of Interfacial Motion at Polystyrene-Alkane Interfaces,"  Macromolecules,  v.39,  2006,  p. 7464.

Ge, L; Sethi, S; Ci, L; Ajayan, PM; Dhinojwala, A.  "Carbon nanotube-based synthetic gecko tapes,"  PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA,  v.104,  2007,  p. 10792 - 10795.  

Kumar Nanjundiah and Ali Dhinojwala.  "Confinement-Induced Ordering of Alkanes between an Elastomer and a Solid Surface,"  Physical Review Letters,  v.95,  2005,  p. 154301.

Sethi, S; Ge, L; Ci, L; Ajayan, PM; Dhinojwala, A.  "Gecko-inspired carbon nanotube-based self-cleaning adhesives,"  NANO LETTERS,  v.8,  2008,  p. 822 - 825.  

Shishir Prasad and Ali Dhinojwala.  "Rupture of a Two-Dimensional Alkane Crystal,"  Physical Review Letters,  v.95,  2005,  p. 117801.

Shishir Prasad, Laurie Hanne and Ali Dhinojwala.  "Thermodynamic Study of a Novel Surface Ordered Phase above the Bulk Melting Temperature in Alkyl Side Chain Acrylate Polymers,"  Macromolecules,  v.38,  2005,  p. 2541.

Shishir Prasad, Laurie Hanne, and Ali Dhinojwala.  "Surface segregation in polymer blends driven by surface freezing,"  Macromolecules,  v.39,  2006,  p. 7467.


(Showing: 1 - 11 of 11).

 

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Last Updated:April 2, 2007