Thermal transport in ultrathin fluoropolymer films

Ghossoub, Marc G.

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https://hdl.handle.net/2142/14731 Copy

Description

Title

Thermal transport in ultrathin fluoropolymer films

Author(s)

Ghossoub, Marc G.

Issue Date

2010-01-06T16:42:04Z

Director of Research (if dissertation) or Advisor (if thesis)

Sinha, Sanjiv

Doctoral Committee Chair(s)

Sinha, Sanjiv

Department of Study

Mechanical Sci & Engineering

Discipline

Mechanical Engineering

Degree Granting Institution

University of Illinois at Urbana-Champaign

Degree Name

M.S.

Degree Level

Thesis

Keyword(s)

• Utrathin Fluorpolymers
• Amorphous
• Thermal Conductivity.

Abstract

Polymers are industrially interesting materials that may contribute inexpensive solutions to nanoscale thermal transport and its numerous applications. In particular, polymers exhibit a shift in their thermal properties when confined to nanometer scales. For instance, ultrathin polymers having thicknesses comparable to the radius of gyration, show a suppression of anharmonicity near the glass transition temperature, which itself is different from the bulk. While thermal properties have been extensively studied for a variety of thick polymers, published thermal conductivity measurements for thin polymer films typically cover thicknesses greater than 100 nm. In this work, time-domain thermoreflectance (TDTR) measurements on fluoropolymer films that are 2.1 to 65 nm thick show an increase in thermal conductivity with decreasing thickness and suggest that a kinetic picture of phonons is over-simplistic when considering ultrathin polymer films with sub-100 nm confinement. This thesis details the work done on measuring the thermal conductivity of ultrathin amorphous fluoropolymer films deposited on Si using a plasma polymerization process. The films are characterized for density, stiffness and composition as a way to shed some light on structural changes that occur with decreasing polymer thicknesses. We show that the increase in thermal conductivity for these amorphous polymers follows the change in film stiffness with different thicknesses and compares well to the minimum thermal conductivity model of amorphous films.

Graduation Semester

2009-12

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http://hdl.handle.net/2142/14731

Copyright and License Information

Copyright 2009 Marc G. Ghossoub

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