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Author: jack douglas
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1. Resonant Microwave Absorption in Thermally Deposited Au Nanoparticle
Films Near Percolation Coverage
Jan Obrzut, Jack F Douglas, Oleg A Kirillov, Fred Sharifi, James Alexander Liddle
We observe a resonant transition in microwave absorption in thin thermally
deposited Au nanoparticle films near the geometrical percolation transition pc where the films
exhibit a ,fractal‰ heterogeneous geometry. The absorption of incident microwa ...
2. Rippling Instability of Supported Polymer Nanolines
Vijaya R. Tirumala, Christopher M Stafford, Leonidas E. Ocola, Jack F Douglas, L. Mahadevan
The swelling response of polymer line gratings supported on a rigid substrate has direct implications on their mechanical stability during pattern transfer in nanofabrication. The polymer lines, when swollen in a good solvent, undergo a rippling inst ...
3. Using Block Copolymer Self-Assembly to Imprint the Crystallization of Polymer Dendrites
Sangcheol Kim, Alamgir Karim, Jack F Douglas, Christopher L Soles, R M Briber
We utilize the self-assembly of cylinder-forming block copolymer (BCP) films to create templates for
dendritic polymer crystallization patterns. This templating was achieved by simply spin-casting thin
films from a solution containing both the BC ...
4. Flexure-induced structural and electronic changes in polymer supported membranes of length purified single-wall carbon nanotubes
John M. Harris, Ganjigunte R.S. Iyer, Daneesh O. Simien, Jeffrey A Fagan, JiYeon Huh, Jun Y. Chung, Steven D Hudson, Jan Obrzut, Jack F Douglas, Christopher M Stafford, Erik K Hobbie
Thin membranes of length purified single-wall carbon nanotubes (SWCNTs) are
uniaxially compressed by depositing them on prestretched polymer substrates. Upon
release of the strain, the topography, microstructure and conductivity of the films are
5. NMR Characterization of the Formation Kinetics and Structure of Di-O-Benzylidene Sorbitol Gels Self-Assembled in Organic Solvents
David Lloyd VanderHart, Jack F Douglas, Steven D Hudson, Joseph M Antonucci, Elizabeth A Wilder
The molecule 1,3:2,4-Di-O-Benzylidene sorbitol (DBS) is a common gelator that forms thermally reversible gels in diverse organic solvents. Solid state 13C and proton NMR techniques, along with electron microscopy, are utilized in an exploratory st ...
6. Thermally-Reversible Surface Morphology Transition Between Cylinders and Spheres in Thin Diblock Copolymer Films
Xiaohua Zhang, Kevin G. Yager, Jack F Douglas
Many phase transitions exhibit ordering transitions at the boundary of the material that are distinct from the interior where the intermolecular interactions can be significantly different. The present result considers the existence of a reversible s ...
7. Dynamic light scattering investigations of nanoparticle aggregation following a light-induced pH jump
Ryan Murphy, Denis Pristinski, Kalman D Migler, Jack F Douglas, Vivek M Prabhu
We use dynamic light scattering to characterize the kinetics of nanoparticle aggregation. The aggregation process was conveniently initiated in photoacid generator (PAG) solutions where changes in the pH of the solution can be controlled by exposure ...
8. Wrinkling and Strain Softening in Single-Wall Carbon Nanotube Membranes
Erik K. Hobbie, Daneesh Olivia Simien, Jeffrey A Fagan, JiYeon Huh, Jun Y. Chung, Steven D Hudson, Jan Obrzut, Jack F Douglas, Christopher M Stafford
Ultrathin layers of single-wall carbon nanotubes (SWCNTs) show considerable promise for applications ranging from fuel-cell membranes and biochemical sensors to bioactive films and transparent electrodes. The high conductivity and extreme anisotropy ...
9. Relaxation and antiplasticization measurements in trehalose-glycerol mixtures; a model formulation for protein preservation
Jan Obrzut, A Anopchenko, Jack F Douglas, Bert W Rust
We utilize dielectric relaxation process for the quantitative characterization of antiplasticization of trehalose by glycerol. The high frequency Johari-Goldstein relaxation time was obtained by analyzing the complex permittivity data in terms of the ...
10. Solvent Retention In Thin Spin-Coated Polystyrene And Poly(Methyl Methacrylate) Homopolymer Films Studied By Neutron Reflectometry
Xiaohua Zhang, Kevin G. Yager, Shuhui Kang, Nathaniel J Fredin, Bulent Akgun, Sushil K Satija, Jack F Douglas, Alamgir Karim, Ronald Leland Jones
We utilize neutron reflectometry (NR) to probe the amount of residual solvent inside thin polystyrene (PS) and poly(methyl methacrylate) (PMMA) films spin-coated from deuterated toluene polymer solutions onto silicon substrates . The effect of therma ...