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You searched for +publisher:"Georgia Tech" +contributor:("Dr. Clifford L. Henderson"). Showing records 1 – 3 of 3 total matches.

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Georgia Tech

1. Singh, Lovejeet. Effect of Nanoscale Confinement on the Physical Properties of Polymer Thin Films.

Degree: PhD, Chemical Engineering, 2004, Georgia Tech

The behavior of polymeric systems confined into thin films is a situation that has numerous practical consequences. One particular application in which the properties of thin polymer films is becoming crucially important is in the design, formulation, and processing of photoresists for semiconductor microlithography. As devices continue to be scaled down into the nano-regime, the microelectronics industry will ultimately rely upon a molecular understanding of materials for process development. The majority of these devices are now confined in planar geometries; thus, thin films have played an ever-increasing role in manufacturing of modern electronic devices. This movement towards thinner resist films creates larger surface to volume ratios, and hence thin films can exhibit thermodynamic, structural, and dynamic properties that are different from those of the bulk material. It is thus extremely important to understand the properties of polymers when confined in such geometries for various applications including resists for lithographic patterning. In present work, the influence of a variety of factors including film thickness, molecular weight, and substrate interactions on the polymer thin film physical properties such as the glass transition temperature, coefficient of thermal expansion, dissolution rate, and diffusion coefficient was studied in detail using a combination of experimental characterization and molecular modeling simulation techniques. Advisors/Committee Members: Dr. Clifford L. Henderson (Committee Chair), Dr. Peter J. Ludovice (Committee Co-Chair), Dr. Carson J. Meredith (Committee Member), Dr. Laren Tolbert (Committee Member), Dr. William J. Koros (Committee Member).

Subjects/Keywords: Diffusion coefficient; Glass transition temperature; Polymer thin films; Thin films; Polymers; Glass transition temperature; Diffusion

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APA (6th Edition):

Singh, L. (2004). Effect of Nanoscale Confinement on the Physical Properties of Polymer Thin Films. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/4822

Chicago Manual of Style (16th Edition):

Singh, Lovejeet. “Effect of Nanoscale Confinement on the Physical Properties of Polymer Thin Films.” 2004. Doctoral Dissertation, Georgia Tech. Accessed January 16, 2021. http://hdl.handle.net/1853/4822.

MLA Handbook (7th Edition):

Singh, Lovejeet. “Effect of Nanoscale Confinement on the Physical Properties of Polymer Thin Films.” 2004. Web. 16 Jan 2021.

Vancouver:

Singh L. Effect of Nanoscale Confinement on the Physical Properties of Polymer Thin Films. [Internet] [Doctoral dissertation]. Georgia Tech; 2004. [cited 2021 Jan 16]. Available from: http://hdl.handle.net/1853/4822.

Council of Science Editors:

Singh L. Effect of Nanoscale Confinement on the Physical Properties of Polymer Thin Films. [Doctoral Dissertation]. Georgia Tech; 2004. Available from: http://hdl.handle.net/1853/4822


Georgia Tech

2. Marla, Krishna Tej. Molecular Thermodynamics of Nanoscale Colloid-Polymer Mixtures: Chemical Potentials and Interaction Forces.

Degree: PhD, Chemical Engineering, 2004, Georgia Tech

Nanoscale colloidal particles display fascinating electronic, optical and reinforcement properties as a consequence of their dimensions. Stable dispersions of nanoscale colloids find applications in drug delivery, biodiagnostics, photonic and electronic devices, and polymer nanocomposites. Most nanoparticles are unstable in dispersions and polymeric surfactants are added generally to improve dispersability and control self-assembly. However, the effect of polymeric modifiers on nanocolloid properties is poorly understood and design of modifiers is guided usually by empirical approaches. Monte Carlo simulations are used to gain a fundamental molecular-level understanding of the effect of modifiers properties on the thermodynamics and interaction forces of nanoscale colloidal particles. A novel method based on the expanded ensemble Monte Carlo technique has been developed for calculation of the chemical potential of colloidal particles in colloid-polymer mixtures (CPM). Using this method, the effect of molecular parameters like colloid diameter, polymer chain length, colloid-polymer interaction strength, and colloid and polymer concentrations, on the colloid chemical potential is investigated for both hard-sphere and attractive Lennard-Jones CPM. The presence of short-chain polymeric modifiers reduces the colloid chemical potential in attractive as well as athermal systems. In attractive CPM, there is a strong correlation between polymer adsorption and colloid chemical potential, as both show a similar dependence on the polymer molecular weight. Based on the simulation results, simple scaling relationships are proposed that capture the functional dependence of the thermodynamic properties on the molecular parameters. The polymer-induced interaction forces between the nanoparticles have been calculated as a function of the above parameters for freely-adsorbing and end-grafted homopolymer modifiers. The polymer-induced force profiles are used to identify design criteria for effective modifiers. Adsorbing modifiers give rise to attractive interactions between the nanoparticles over the whole parameter range explored in this study. Grafted surface modifiers lead to attraction or repulsion based on the polymer chain length and grafting density. The polymer-induced attraction in both adsorbing and grafted modifiers is attributed primarily to polymer intersegmental interactions and bridging. The location of the thermodynamic minimum corresponding to the equilibrium particle spacing in nanoparticle-polymer mixtures can be controlled by tuning the modifier properties. Advisors/Committee Members: Dr. J. Carson Meredith (Committee Chair), Dr. Charles A. Eckert (Committee Member), Dr. Clifford L. Henderson (Committee Member), Dr. Peter J. Ludovice (Committee Member), Dr. Rigoberto Hernandez (Committee Member).

Subjects/Keywords: Nanoparticle interaction forces; Colloid chemical potential; Nanoparticle-polymer systems; Colloid-polymer mixtures

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Marla, K. T. (2004). Molecular Thermodynamics of Nanoscale Colloid-Polymer Mixtures: Chemical Potentials and Interaction Forces. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/7604

Chicago Manual of Style (16th Edition):

Marla, Krishna Tej. “Molecular Thermodynamics of Nanoscale Colloid-Polymer Mixtures: Chemical Potentials and Interaction Forces.” 2004. Doctoral Dissertation, Georgia Tech. Accessed January 16, 2021. http://hdl.handle.net/1853/7604.

MLA Handbook (7th Edition):

Marla, Krishna Tej. “Molecular Thermodynamics of Nanoscale Colloid-Polymer Mixtures: Chemical Potentials and Interaction Forces.” 2004. Web. 16 Jan 2021.

Vancouver:

Marla KT. Molecular Thermodynamics of Nanoscale Colloid-Polymer Mixtures: Chemical Potentials and Interaction Forces. [Internet] [Doctoral dissertation]. Georgia Tech; 2004. [cited 2021 Jan 16]. Available from: http://hdl.handle.net/1853/7604.

Council of Science Editors:

Marla KT. Molecular Thermodynamics of Nanoscale Colloid-Polymer Mixtures: Chemical Potentials and Interaction Forces. [Doctoral Dissertation]. Georgia Tech; 2004. Available from: http://hdl.handle.net/1853/7604


Georgia Tech

3. Pathak, Shantanu Chaturvedi. Characterization of plasma-polymerized polyethylene glycol-like films.

Degree: PhD, Chemical Engineering, 2008, Georgia Tech

A parallel-plate capacitively-coupled plasma deposition system was designed and built for the growth of polyethylene glycol-like films. Deposition rate, bonding structure and dissolution and swelling behavior was characterized as a function of input RF power, reactor pressure and substrate temperature to provide information on the relationship between input plasma parameters and film properties. For the conditions studied in this thesis, deposition rates increased at increasing input powers and operating pressures and decreasing substrate temperatures. The PEG-like coatings resembled higher molecular weight solution-polymerized PEG films with a higher crosslinked structure. Manipulation of plasma deposition conditions allowed control of film crosslink density and resulted in tunable dissolution and swelling properties of the PEG-like polymer. At higher applied powers, lower operating pressures, and higher substrate temperatures, films had a higher crosslink density, thus leading to slower dissolution rates and smaller extents of swelling. Void space openings of swelled-state, PEG-like films were determined using electrophoretic drift and diffusion-controlled transport of fluorophore-tagged PAMAM dendrimers into the bulk of the coating. PAMAM dendrimers were used because of their well-defined sizes and negatively-charged succinamic acid surface groups as a means to probe pore sizes of the plasma films. It was estimated that the upper bound of pore size diameters in the plasma polymer was approximately equal to ~5.5-6.0 nm. Positron annihilation lifetime spectroscopy was used to determine average pore sizes and was estimated to equal ~0.60-0.65 nm. Advisors/Committee Members: Dr. Dennis W. Hess (Committee Chair), Dr. Clifford L. Henderson (Committee Member), Dr. J. Carson Meredith (Committee Member), Dr. L. Andrew Lyon (Committee Member), Dr. Mark R. Prausnitz (Committee Member).

Subjects/Keywords: Barrier film; Plasma polymerization; Stent; Biomedical materials Research; Medical instruments and apparatus; Thin films

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Pathak, S. C. (2008). Characterization of plasma-polymerized polyethylene glycol-like films. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/31789

Chicago Manual of Style (16th Edition):

Pathak, Shantanu Chaturvedi. “Characterization of plasma-polymerized polyethylene glycol-like films.” 2008. Doctoral Dissertation, Georgia Tech. Accessed January 16, 2021. http://hdl.handle.net/1853/31789.

MLA Handbook (7th Edition):

Pathak, Shantanu Chaturvedi. “Characterization of plasma-polymerized polyethylene glycol-like films.” 2008. Web. 16 Jan 2021.

Vancouver:

Pathak SC. Characterization of plasma-polymerized polyethylene glycol-like films. [Internet] [Doctoral dissertation]. Georgia Tech; 2008. [cited 2021 Jan 16]. Available from: http://hdl.handle.net/1853/31789.

Council of Science Editors:

Pathak SC. Characterization of plasma-polymerized polyethylene glycol-like films. [Doctoral Dissertation]. Georgia Tech; 2008. Available from: http://hdl.handle.net/1853/31789

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