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Blessing Deeyaa, Christopher Stafford, Edwin Chan, Peter M. Johnson
In this work, we study the viscoelastic and poroelastic contributions on the relaxation behavior of a polymer-loaded hydrogel using a recently develop Poroelastic Relaxation Indentation (PRI) measurement technique. By applying a generalized relaxation
Stephanie S. Watson, I-Hsiang Tseng, Tarek Marray, Bastien T. Pellegrin
The service life and durability of nanocomposites that contain fillers are affected by photocatalytic properties of these fillers, particularly narrow band gap metal oxides (NBMOs) such as titanium dioxide (TiO2). When illuminated with ultraviolet (UV)
Ionenes are polyelectrolytes with the charge along the polymer backbone. These polymers possess a precisely-defined charge density, making them ideal as physical crosslinkers for high performance elastomers as well as gene transfection agents. However
Jae Hyun Kim, Nathanael A. Heckert, Stefan D. Leigh, Haruki Kobayashi, Walter G. McDonough, Richard L. Rhorer, Kirk D. Rice, Gale A. Holmes
The Kolsky bar test has been widely used in measuring material behavior under high strain rate conditions. In particular, this methodology has been used to characterize the high strain rate behavior of polymer and polymer composites during ballistic impact
Jae Hyun Kim, Nathanael A. Heckert, Stefan D. Leigh, Haruki Kobayashi, Walter G. McDonough, Kirk D. Rice, Gale A. Holmes
A new single fiber tensile test method using the Kolsky bar is being utilized to investigate fiber properties under high strain rate conditions. Since fiber tensile properties exhibit broad, dispersed distributions, a large number of test specimens are
Adrian E. Verwolf, Grady S. White, Chris M. Poling
Roughness and nanomechanical properties of poly(chloro-para-xylylene) coatings are shown to be affected by both chemical composition and surface roughness of four different metallic substrates. Nanoindentation was used to determine reduced elastic modulus
David E. Morris, Melissa L. Mather, Carl Simon Jr., John A. Crowe
The performance of polymer based scaffolds used in regenerative medicine is linked to their structural properties and as such strategies for structural characterization of scaffolds have been developed. X-ray microscopic computed tomography (X-ray micro CT
Dalia Yablon, Anil Gannepalli, Roger Proksch, Jason Killgore, Donna C. Hurley, Andy Tsou
The storage modulus (E') and loss modulus (E") of polyolefin blends have been mapped on the nanoscale with contact resonance force microscopy (CR-FM), a dynamic contact mode of atomic force microscopy (AFM). CR-FM maps for a blend of polyethylene
Carl G. Simon Jr., Kaushik Chatterjee, Alison M. Kraigsley, Joachim Kohn, Durgadas Bolikal
Current methods for screening cell-material interactions typically utilize two-dimensional (2D) culture format where cells are cultured on flat surfaces. However, there is a need for combinatorial and high-throughput screening methods to systematically
The need for bone defect repair and regeneration arises from trauma, disease, congenital deformity, and tumor resection. Bone fracture occurs to seven million people each year in the United States, and musculoskeletal conditions cost $215 billion annually
Conni Hanke, Petra S. Dittrich, Darwin Reyes-Hernandez
A new system for dielectrophoretic cell capture on porous polyester (PET) membranes is presented. Conventional photolithographic techniques were used to fabricate gold microelectrodes on a PET membrane. We characterized these electrodes to proof that there
There are diverse material science problems concerned with how the presence of a low concentration of particulate inclusions having mechanical properties distinct from the matrix in which they are placed influences the elasticity of the resulting composite
Matthew T. Hunley, Santanu S. Kundu, Peter M. Johnson, Kathryn Beers
Recent advances in enzyme, metal, and organic catalysts have enabled the development of advanced functional polymers from cyclic ester and cyclic carbonate monomers. In this work, we present an in situ technique to monitor ring-opening polymerization using
Girish Kumar, Carl G. Simon Jr., Michael S. Waters, Tanya M. Farooque, Marian F. Young
We demonstrate that imparting freeform fabricated (FFF) scaffolds with surface roughness on their struts enhances osteogenic differentiation of primary human bone marrow stromal cells (hBMSCs) by controlling cell shape. Previous work showed that hBMSCs
Fan Zhang, Andrew Allen, Lyle E. Levine, Laura Espinal, Joseph M. Antonucci, Drago Skrtic, Justin N. O'Donnell, Jan Ilavsky
The local structural changes in amorphous calcium phosphate (ACP) based dental composites were studied upon heating using both static, bulk measurement techniques and recently developed ultra-small angle X-ray scattering - X-ray photon correlation
Lei Cheng, Michael D. Weir, Hockin H. Xu, Alison M. Kraigsley, Nancy Lin, Sheng Lin-Gibson, Xuedong Zhou
Secondary caries limits the longevity of tooth restorations. The replacement of existing restorations accounts for 50-70% of all restorations. Replacement dentistry costs $5 billion in the U.S. annually. The objectives of this study were to (1) develop
Edwin Chan, Yuhang Hu, Peter M. Johnson, Zhigang Suo, Christopher Stafford
In this work, we present the Poroelastic Relaxation Indentation (PRI) testing approach for quantifying the mechanical and transport properties of thin layers of poly(ethylene glycol) hydrogel materials with thicknesses on the order of 200 m. Specifically
Three fundamental mechanical properties of supported glassy polystyrene films with thickness ranging from 250 nm to 9 nm were quantitatively determined by a recently developed wrinkling-cracking method. Films below about 40 nm showed a decrease in both
Peter M. Johnson, Joonsung (. Yoon, Jennifer Y. Kelly, John A. Howarter, Christopher Stafford
In membranes for reverse osmosis and nanofiltration, the discriminating layers consist of an interfacially polymerized polyamide film on a porous support. For reverse osmosis membranes, the dominant commercial interfacial film is a crosslinked network
Jessica M. Torres, Christopher Stafford, David Uhrig, Bryan D. Vogt
The modulus and Tg of a series of PS samples with varying architecture are examined in thin films as a function of thickness. The bulk-like, thick film Tg is independent of polymer architecture: linear, comb, centipede and 4 armed star PS. However for
Matthew T. Hunley, Atul Bhangale, Santanu S. Kundu, Peter M. Johnson, Michael S. Waters, Richard Gross, Kathryn Beers
In situ, fiber optic-based Raman spectroscopy provided real time monitoring of enzyme-catalyzed ring-opening homo- and copolymerizations of ε-caprolactone (ε-CL) and δ-valerolactone (δ-VL). A custom designed reactor equipped with in situ fiber optic probe
Joseph M. Antonucci, Diana N. Zeiger, Sheng Lin-Gibson, Bruce O. Fowler, Nancy J. Lin
The widespread incidence of recurrent caries has resulted in the need for improved dental restorative materials, including effective antibacterial, polymeric dental materials. Compounds with quaternary ammonium groups are known to reduce bacterial growth
Douglas M. Fox, Richard H. Harris Jr., Jeffrey W. Gilman
The use of natural and non-toxic compounds to improve the properties of polymers has received significant attention over the past decade. In this study, a polyhedral oligomeric silsesquioxane (POSS) tethered imidazolium surfactant was used to exchange
Jessica M. Torres, Chengqing C. Wang, E. B. Coughlin, John P. Bishop, Richard A. Register, Robert A. Riggleman, Christopher Stafford, Bryan D. Vogt
The effect of main chain stiffness and side chain flexibility on the elastic modulus and glass transition temperature (Tg) of thin polymer films is investigated using non-traditional polymers formed from 5-(2-phenylethylnorbornene). Depending on the