2026-09-23T14:21:55Z https://www.ideals.illinois.edu/oai-pmh

oai:www.ideals.illinois.edu:2142/50413 2023-07-11 col_2142_5131 col_2142_14787 com_2142_5130 com_2142_9630 com_2142_234

Embargo set by: Seth Robbins for item 50524 Lift date: 2016-09-16T17:13:01Z Reason: Author requested closed access (OA after 2yrs) in Vireo ETD system Limited Restriction Lifted for Item 50524 on 2016-09-22T20:59:15Z. http://hdl.handle.net/2142/50413 en Copyright 2014 Mete Bakir Quantitave Viscoelastic Spectroscopy Nanomechanical Characterization Block Copolymers Morphologies Multi-Frequency Atomic Force Microscopy (AFM) Cantilever Mathematical Modelling Contact Resonance Atomic Force Microscopy (AFM) Quantitative viscoelastic spectroscopy of polymer films using Lorentz force actuated contact resonance atomic force microscopy text King, William P. Bakir, Mete 2014-09-16T17:12:43Z 2014-09-16T17:12:43Z 2016-09-22T20:59:15Z 2014-08 2014-09-16 2014-08 This thesis presents development of a material metrology technique, which is shown to quantify viscoelastic properties of a polymer film within the glass transition region. Designed for nanoscale material characterization applications, heater integrated atomic force microscopy (AFM) cantilever operates in contact resonance mode actuated by externally induced Lorentz force. It is demonstrated that glass transition temperature (Tg) of polymethyl methacrylate (PMMA) film can be detected reproducibly by monitoring contact resonance frequency of the cantilever as a function of temperature. Also, the glass transition temperature is observed in the terms of differential change of cantilever electrical resistance and differential power consumption. Furthermore, employing a harmonic oscillator model to define tip-sample contact interactions, viscoelastic properties of contact stiffness, viscous damping coefficient and elastic modulus for the polymer film are measured as functions of temperature. In addition, multi-frequency actuation for contact resonance is demonstrated providing qualitative material properties. Besides, a mathematical approach is developed to model two-leg and V-shaped LCR cantilevers as in the form of rectangular beam. Finally, local viscoelastic measurements taken on 66-63K PS-PMMA lamellar block copolymer film are presented. Also, nanomechanical surface property mappings of both 37-37K PS-PMMA lamellar and 46-21K PS-PMMA cylindrical block copolymer morphologies are provided. The technique introduced in this work has vast potential to be employed for numerous nano-scale material applications, and eventually replace traditional macro-scale thermophysical material characterization technologies providing local, reproducible and non-destructive analyses. Item withdrawn by Laura Spradlin (lspradl2@illinois.edu) on 2014-07-22T22:12:08Z Item was in collections: University of Illinois Theses & Dissertations (ID: 1) No. of bitstreams: 1 Bakir_Mete.pdf: 3026697 bytes, checksum: 5b8acc886f95dfdc591d62a074f7df57 (MD5) Made available in DSpace on 2014-09-16T17:12:43Z (GMT). No. of bitstreams: 2 Mete_Bakir.pdf: 3026762 bytes, checksum: 5ef7f547c910eceffd01eb3b5d6c84b9 (MD5) license.txt: 4058 bytes, checksum: a8430874e783cd5e63bdb7fa553945c9 (MD5) Thesis Mechanical Sci & Engineering 1917 Mechanical Engineering 0133 University of Illinois at Urbana-Champaign M.S. MS:Mechanical Engineerng -UIUC 10KS0133MS