Browsing by Author "Winton, BR"

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    Control of time-dependent buckling patterns in thin confined elastomer film
    (Materials Research Society, 2010-10) Winton, BR; Ionescu, M; Dou, SX
    Low energy metal ion implantation has been used to combine an easy “bottom-up” way of creating and tuning different topographic structures on submicron to micrometer scales with the embedding of a metallic element-rich functionalized layer at the surface for a variety of scientific and technological applications. The self-organizing and complex patterns of functionalized topographic structures are highly dependent on the implanted metal ion species, variations in the geometric confinement of the buckled areas on the larger unmodified elastomer film, and the boundary conditions of the buckled regions. Systematic investigations of these dependencies have been carried out via optical and atomic force microscopy, and confirmed with cross-sectional transmission electron microscopy. © 2010, Materials Research Society
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    Enhanced biocompatibility of PDMS (polydimethylsiloxane) polymer films by ion irradiation
    (Elsevier B.V., 2012-02-15) Ionescu, M; Winton, BR; Wexler, D; Siegele, R; Deslantes, A; Stelcer, E; Atanacio, AJ; Cohen, DD
    PDMS films several microns thick deposited on polished Si wafers were irradiated with Mg, Ta, and Fe in the low energy range of 40 keV to 200 keV, and for doses of 1016–1018 ions/cm2. After irradiation the films surface is self-organised into 3D coherent and semi-coherent domains. As a consequence of the surface irradiation conditions and the surface boundary conditions, some domains are highly ordered in the form of parallel waves of approximately 1 μm in height, or the result can be semi-ordered regions or disordered regions. In addition, the surface energy of the irradiated polymer is increasing, as reflected in the decrease in its surface hydrophobicity, which is beneficial for cell adhesion. The irradiated samples were tested in vivo, and the results show an increase in viable cell count of up to 650%. © 2020 Elsevier B.V
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    Irradiation Si on carbon nanotube paper as a flexible anode material for lithium-ion batteries
    (American Scientific Publishers, 2012-02-01) Chou, SL; Ionescu, M; Wang, JZ; Winton, BR; Liu, HK
    Silicon/single-walled carbon nanotube (SWCNT) composite paper was modified by low energy ion implantation using Si to obtain a flexible composite paper. Raman and FE-SEM results show that structure of SWCNT could be destroyed by the implantation. Electrochemical measurements display that the implanted Si can improve the specific capacity and the reversible capacity of CNT paper. After 50 cycles, the specific capacity of Si-implanted CNT paper is 30% higher than the pristine CNT. © 2020 Ingenta
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    Structural and morphological modification of PDMS thick film surfaces by ion implantation with the formation of strain-induced buckling domains
    (Elsevier, 2010-03) Winton, BR; Ionescu, M; Dou, SX; Wexler, D; Alvarez, GA
    Elastomer films with three-dimensional features self-organized into coherent and semi-coherent buckling domains were created by implanting different species of metal ions and combinations thereof, using a metal evaporation ion source, into quality polydimethylsiloxane films. As a result of the implantation process, functionalized discrete regions of strain-induced surface buckling were created, taking the forms of domains of parallel surface waves, semi-ordered regions and disordered regions. In addition, deep, strain-induced, V-shaped cracks were observed to penetrate well into the elastomer matrix. Characterization was via optical microscopy, X-ray diffraction, atomic force microscopy and high-resolution scanning electron microscopy (SEM) in the form of field emission SEM. It was found that controlling the localized strain by altering the metal ion species can control the frequency of the V-shaped cracks and the properties of the buckled areas. These observations and possible mechanisms for the formation of the cracks and domains are discussed in this paper. © 2010, Elsevier Ltd.