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LindsayElliott

Lindsay Elliott

Graduate Student in Chemistry

Advised by Paul W. Bohn and Paul V. Braun

B.S. in Chemistry with Distinction , Purdue University (2005)

Single particle tracking for characterization of nanoscale perturbation-induced swelling in 2-hydroxyethylmethacrylate and N-isopropylacrylamide polymer films

Tracking of single particle fluorescence is used to determine thickness and morphological changes in stimulus-responsive polymer films, including pHEMA and pNIPAAm, which are grown through a ‘grafting-from’ ATRP (Atom Transfer Radical Polymerization) synthesis on bromine terminated initiator self-assembled monolayers on Au.  These polymer materials respond to external stimuli by absorbing or expelling hydrated ions from the surrounding solution, with resulting free volume effects and changes in film thickness.  Characterization of initiator and polymer surfaces is carried out through X-ray photoelectron spectroscopy, IR, ellipsometry, and profilometry as well as environmental scanning electron microscopy and wet mode AFM techniques.  In addition to those with full surface coverage, samples of different polymer densities are prepared by varying initiator ratios, and electrochemical gradients are created through desorption of dense polymer brushes.

Fluorescent particles (shown as solid green circles in figure above) within films with dry thicknesses between 100-250nm are tracked, and diffusion data is determined at different swelling states by following the spatial position of a single particle fluorescent probe.  The diffraction limit of light is overcome by using mathematical techniques to map the intensity profile of each particle frame-by-frame and trajectories are created by linking these points together, based on user supplied parameters (see pictoral representation below).

Basic diffusion equations are utilized to calculate free volume changes, and then thickness changes are determined.  Information is gained about pore size and distribution, nanoscale changes in film thickness, chain-to-chain and chain-to-particle interactions.  Fine control of hydrogel swelling is currently being applied to drug delivery and to create mass selective gates with tunable pore diameters.  Possible molecular selective gate shown below.

 

EDUCATION

            University of Illinois    Urbana-Champaign, IL            May 2009       

            Doctor of Philosophy in Chemistry                             

            National Defense Science and Engineering Graduate Fellowship, National Science Foundation Graduate Research Fellowship, University of Illinois Roger Adams Fellowship 

Purdue University        West Lafayette, IN                   May 2003

Bachelor of Science in Chemistry with Distinction       Minor: Physics            

 

RESEARCH EXPERIENCE

Graduate Research (December 2004-present)

Advisors:

Paul W. Bohn, Arthur J. Schmitt Professor of Chemical and Biomolecular Engineering and Professor of Chemistry, Department of Chemical and Biomolecular Engineering, University of Notre Dame

Paul V. Braun, Associate Professor of Material Science and Engineering, Willett Faculty Scholar of Engineering, University of Illinois, U-C

Project

Graduate Research (June-September 2003)

Advisor:  Ralph G. Nuzzo, William H. and Janet Lycan Professor of Chemistry, Professor of Materials Science and Engineering, University of Illinois, U-C

Project

Undergraduate Research (April 2000-May 2003)

Advisor:  Jillian M. Buriak, Associate Professor, Department of Chemistry, Purdue University

TEACHING  EXPERIENCE

Chemistry 102D, General Chemistry I (UIUC, Spring 2005)- Principles governing atomic structure, bonding, states of matter, stoichiometry, and chemical equilibrium; descriptive chemistry of the elements and coordination compounds.

Chemistry Learning Center Tutor (UIUC, Fall 2004)- Goals of the learning center included providing free tutoring services and an atmosphere conducive to learning.

Chemistry 203, Advanced Chemistry Lab I (UIUC, Fall 2004)- Students are expected to discuss concepts and techniques, describe implications of the results in a formal report, and display critical thinking in making connections between theory and experiment.

Chemistry Resource Room Tutor (Purdue, Fall 2002-Spring 2003)- Goals of the resource room included aiding students in learning of chemistry as well as building confidence in their abilities to effectively apply the subject matter. 

PUBLICATIONS AND PRESENTATIONS

Professor Paul Braun • Phone: +1.217.244.7293 • Fax: +1.217.333.2736 • Email: pbraun@illinois.edu
Department of Materials Science and Engineering • University of Illinois at Urbana-Champaign