In: Journal of Micromechanics and Microengineering, 2011, vol. 21, no. 5, p. 054009
This paper reports the development of micromachining processes and mechanical evaluation of a stimuli-responsive, mechanically dynamic polymer nanocomposite for biomedical microsystems. This nanocomposite consists of a cellulose nanofiber network encased in a polyvinyl acetate matrix. Micromachined tensile testing structures fabricated from the nanocomposite displayed a reversible and switchable...
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In: Polymer Chemistry, 2010, vol. 1, no. 8, p. 1237-1244
Cellulose nanofibers or “whiskers” derived from tunicates were coated with PEDOT:PSS to produce high-aspect-ratio nanorods with high electrical conductivity. Films made from these PEDOT:PSS whiskers have surface resistivities as low as 97 Ω/□. The nanorods were found to disperse well in polar organic solvents such as dimethylformamide, which allowed the fabrication of nanocomposites with...
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In: ACS Applied Materials and Interfaces, 2010, vol. 2, no. 4, p. 1073-1080
New nanocomposites composed of cellulose nanofibers or “whiskers” and an epoxy resin were prepared. Cellulose whiskers with aspect ratios of ∼10 and ∼84 were isolated from cotton and sea animals called tunicates, respectively. Suspensions of these whiskers in dimethylformamide were combined with an oligomeric difunctional diglycidyl ether of bisphenol A with an epoxide equivalent weight...
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In: Biomacromolecules, 2010, vol. 11, no. 3, p. 762–768
Quantitative insights into the stress-transfer mechanisms that determine the mechanical properties of tunicate cellulose whisker/poly(vinyl acetate) nanocomposites were gained by Raman spectroscopy. The extent of stress-transfer is influenced by local orientation (or anisotropy) of the whiskers, which in turn is governed by the processing conditions used to fabricate the nanocomposites....
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In: Langmuir, 2010, vol. 26, no. 11, p. 8497–8502
Biological systems such as proteins, viruses, and DNA have been most often reported to be used as templates for the synthesis of functional nanomaterials, but the properties of widely available biopolymers, such as cellulose, have been much less exploited for this purpose. Here, we report for the first time that cellulose nanocrystals (CNC) have the capacity to assist in the synthesis of metallic...
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In: Progress in Polymer Science, 2010, vol. 35, no. 1-2, p. 212–222
The development of a new class of mechanically adaptive nanocomposites has been inspired by biological creatures such as sea cucumbers, which have the ability to reversibly change the stiffness of their dermis. Several recent studies have related this dynamic mechanical behaviour to the distinctive nanocomposite architecture of the collagenous tissue, in which interactions among rigid collagen...
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In: Journal of Materials Chemistry, 2010, vol. 20, p. 180-186
A new series of biomimetic, stimuli-responsive nanocomposites, which change their mechanical properties upon exposure to physiological conditions, was investigated. The materials were produced by introducing percolating networks of cellulose whiskers isolated from cotton into poly(vinyl acetate). Below the glass-transition temperature (Tg∼ 63 °C), the tensile storage moduli...
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In: ACS Applied Materials & Interfaces, 2009, vol. 2, no. 1, p. 165–174
A new series of biomimetic stimuli-responsive nanocomposites, which change their mechanical properties upon exposure to physiological conditions, was prepared and investigated. The materials were produced by introducing percolating networks of cellulose nanofibers or “whiskers” derived from tunicates into poly(vinyl acetate) (PVAc), poly(butyl methacrylate) (PBMA), and blends of these...
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In: Macromolecular Chemistry and Physics, 2009, vol. 211, no. 1, p. 28-34
Cyano-substituted excimer-forming oligo(phenylene vinylene) dyes (cyano-OPVs) with terminal alkyl tails of different length were blended with two fluorinated host polymers with similar chemical composition but differing crystallinity. These blends were used to fabricate luminogenic mechanochromic thin films, which change their emission color upon deformation. The alkyl tails affect the solubility...
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In: Journal of the American Chemical Society, 2009, vol. 131, no. 33, p. 12007–12014
The upconverting properties of a dye cocktail composed of palladium(II) octaethylporphyrin (PdOEP, triplet sensitizer) and 9,10-diphenylanthracene (DPA, triplet acceptor/annihilator) were investigated as a function of temperature in several low glass transition temperature (Tg) polymer hosts including an ethyleneoxide-epichlorohydrin copolymer (EO-EPI) and the polyurethanes...
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