@article{gong_spagnola_arvidson_khan_parsons_2012, title={Directed inorganic modification of bi-component polymer fibers by selective vapor reaction and atomic layer deposition}, volume={53}, ISSN={["1873-2291"]}, url={http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=ORCID&SrcApp=OrcidOrg&DestLinkType=FullRecord&DestApp=WOS_CPL&KeyUT=WOS:000309377400009&KeyUID=WOS:000309377400009}, DOI={10.1016/j.polymer.2012.08.018}, abstractNote={Abstract Nanocomposite organic/inorganic materials with spatially-controlled composition can be formed using vapor-phase atomic layer deposition (ALD) on bi-component polymer fibers. The ALD process promotes selective precursor infusion into the inner core of a core/shell polymer fiber, yielding nanoparticles encapsulated within the core. Likewise, choosing alternate precursors or reaction conditions yield particles or films on the outer polymer shell. In-situ infrared spectroscopy and transmission electron microscopy show that infusion yields selective dispersion of aluminum oxide in different polymer regions, forming fine nanoparticle dispersions or films. Selective inclusion of metal oxide materials during atomic layer deposition on polymers can create unique organic/inorganic composite structures for many advanced uses.}, number={21}, journal={POLYMER}, author={Gong, Bo and Spagnola, Joseph C. and Arvidson, Sara A. and Khan, Saad A. and Parsons, Gregory N.}, year={2012}, month={Sep}, pages={4631–4636} }
 @article{arvidson_roskov_pate_spontak_khan_gorga_2012, title={Modification of Melt-Spun Isotactic Polypropylene and Poly(lactic acid) Bicomponent Filaments with a Premade Block Copolymer}, volume={45}, ISSN={["1520-5835"]}, DOI={10.1021/ma202246h}, abstractNote={While numerous studies have investigated the effect of adding a block copolymer as a macromolecular surfactant to immiscible polymer blends, no such efforts have sought to alter the properties of melt-spun bicomponent core–sheath filaments with a nonreactive compatibilizing agent. In this study, we examine the effect of adding poly[styrene-b-(ethylene-co-butylene)-b-styrene] (SEBS) triblock copolymer to core–sheath filaments consisting of isotactic polypropylene (iPP) and poly(lactic acid) (PLA). Incorporation of the copolymer into blends of iPP/PLA is observed to reduce the size scale of phase separation. Interfacial slip between molten iPP and PLA layers is evaluated by rheology under steady-shear conditions. Addition of SEBS to the PLA sheath during filament formation reduces the tendency of PLA sheaths to crack prior to iPP core failure during tensile testing. In reversed filament configurations, the copolymer does not hinder the development of molecular orientation, related to fiber strength, during ...}, number={2}, journal={MACROMOLECULES}, author={Arvidson, Sara A. and Roskov, Kristen E. and Pate, Jaimin J. and Spontak, Richard J. and Khan, Saad A. and Gorga, Russell E.}, year={2012}, month={Jan}, pages={913–925} }
 @article{arvidson_wong_gorga_khan_2012, title={Structure, molecular orientation, and resultant mechanical properties in core/sheath poly(lactic acid)/polypropylene composites}, volume={53}, ISSN={["0032-3861"]}, DOI={10.1016/j.polymer.2011.12.042}, abstractNote={We study the coaxial spinning of poly(lactic acid) (PLA) with polypropylene (PP) in a core/sheath configuration. PPcore/PLAsheath and PLAcore/PPsheath fibers maintain the high breaking strength that PP and PLA exhibit individually, showing marked improvement in strength over previous reports of PP/PLA blend fibers. Crystalline morphologies are greatly affected by the location within the fiber (i.e., core, sheath, or spun individually), and hence, co-spinning provides a route to tailor the morphology and fiber diameter beyond that available with single component fibers. A new approach to estimate molecular orientation of core sheath fibers based on the tensile response of the fiber is developed, and indicates that co-spinning PP with PLA results in a synergistic effect with increases in the molecular orientation above that which is possible with spinning either PP or PLA individually.}, number={3}, journal={POLYMER}, author={Arvidson, Sara A. and Wong, Ka C. and Gorga, Russell E. and Khan, Saad A.}, year={2012}, month={Feb}, pages={791–800} }
 @article{arvidson_khan_gorga_2010, title={Mesomorphic-alpha-Monoclinic Phase Transition in Isotactic Polypropylene: A Study of Processing Effects on Structure and Mechanical Properties}, volume={43}, ISSN={["1520-5835"]}, DOI={10.1021/ma1001645}, abstractNote={We report the enthalpy for the mesomorphic to α-monoclinic phase transition in polypropylene under varying thermal treatments. The mesomorphic phase is created by fiber spinning and rapid quenching methods and identified using wide-angle X-ray diffraction and differential scanning calorimetry. Fiber mesomorphs are found to have a 3-fold increase in enthalpy of transition per gram of mesophase compared with our measurements of quenched polypropylene and previous reports of quenched polypropylene. In addition, systematic tensile testing over a range of spin speeds and polymer morphologies reveals that the presence of mesomorphic regions does not correlate with reduced fiber strength as has been previously suggested. Fiber true stress−true strain curves obtained at varying take-up velocities are compared to determine the “tensile strain shift”, which should theoretically provide a measure of molecular orientation. We find that the tensile strain shift correlates with birefringence, thereby providing an alter...}, number={6}, journal={MACROMOLECULES}, author={Arvidson, Sara A. and Khan, Saad A. and Gorga, Russell E.}, year={2010}, month={Mar}, pages={2916–2924} }
 @article{spagnola_gong_arvidson_jur_khan_parsons_2010, title={Surface and sub-surface reactions during low temperature aluminium oxide atomic layer deposition on fiber-forming polymers}, volume={20}, ISSN={["0959-9428"]}, url={http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=ORCID&SrcApp=OrcidOrg&DestLinkType=FullRecord&DestApp=WOS_CPL&KeyUT=WOS:000277563800026&KeyUID=WOS:000277563800026}, DOI={10.1039/c0jm00355g}, abstractNote={Fundamental reaction processes between vapor-phase chemical precursors and high molecular weight polymers are important for polymer coating, encapsulation and surface modification. Using trimethylaluminium and water in an atomic layer deposition (ALD) exposure sequence, reactions between vapor-phase trimethylaluminium and common polymers with different substituents are quantified using in situ infrared transmission analysis. Exposing polypropylene to trimethylaluminium results in reactant uptake with minimal precursor/polymer reaction, but the precursor/water ALD sequence leads to subsurface alumina nucleation. A similar treatment to polyvinyl alcohol and polyamide-6 results in rapid precursor diffusion and significant reaction observed by IR, and the extent of reaction is consistent with results from in situ quartz crystal microgravimetry and transmission electron microscopy. Reacting trimethylaluminium with polyamide-6 leads to methyl group insertion into the amide carbonyl group and interaction with the hydrogen-bonded amine units. Multiple ALD reaction cycles produce film coatings on all polymers studied, but the coating structure depends strongly on the starting polymer composition. For the weakly interacting polypropylene, cross-sectional transmission electron microscopy demonstrates enhanced sub-surface growth at 90 °C as compared to that at 60 °C, while images of coated polyamide-6 fibers showed that growth is not strongly temperature dependent in that range. Micrograph images of polyamide-6 samples exposed to extended TMA doses revealed significant modification of the fiber surface region, demonstrating that the precursor could diffuse and react to depths in excess of 100 nm into the surface of the polymer at 90 °C. Improved understanding of specific precursor/polymer reaction pathways can be important to optimize the performance of conformal inorganic thin film coatings on polymers.}, number={20}, journal={JOURNAL OF MATERIALS CHEMISTRY}, author={Spagnola, Joseph C. and Gong, Bo and Arvidson, Sara A. and Jur, Jesse S. and Khan, Saad A. and Parsons, Gregory N.}, year={2010}, pages={4213–4222} }
 @article{pirzada_arvidson_saquing_shah_khan, title={Hybrid carbon silica nanofibers through sol-gel electrospinning}, volume={30}, number={51}, journal={Langmuir}, author={Pirzada, T. and Arvidson, S. A. and Saquing, C. D. and Shah, S. S. and Khan, S. A.}, pages={15504–15513} }
 @article{pirzada_arvidson_saquing_shah_khan, title={Hybrid silica-PVA nanofibers via sol-gel electrospinning}, volume={28}, number={13}, journal={Langmuir}, author={Pirzada, T. and Arvidson, S. A. and Saquing, C. D. and Shah, S. S. and Khan, S. A.}, pages={5834–5844} }