Université de Fribourg

Stress transfer in cellulose nanowhisker composites—Influence of whisker aspect ratio and surface charge

Rusli, Rafeadah ; Shanmuganathan, Kadhiravan ; Rowan, Stuart J. ; Weder, Christoph ; Eichhorn, Stephen J.

In: Biomacromolecules, 2011, vol. 12, no. 4, p. 1363–1369

The mechanically induced molecular deformation of cellulose nanowhiskers embedded in subpercolation concentration in an epoxy resin matrix was monitored through Raman spectroscopy. Cellulose nanowhiskers isolated by sulfuric acid hydrolysis from tunicates and by sulfuric acid hydrolysis and hydrochloric acid hydrolysis from cotton were used to study how the aspect ratio (ca. 76 for tunicate and...

Université de Fribourg

Biologically inspired hierarchical design of nanocomposites based on poly(ethylene oxide) and cellulose nanofibers

Changsarn, Sutheerat ; Mendez, James D. ; Shanmuganathan, Kadhiravan ; Foster, E. Johan ; Weder, Christoph ; Supaphol, Pitt

In: Macromolecular Rapid Communications, 2011, vol. 32, no. 17, p. 1367–1372

Attempts to create hierarchically structured, uniaxially oriented nanocomposites comprising cellulose nanowhiskers (CNWs), which promise anisotropic mechanical properties, are exceedingly rare. We report here the fabrication of uniaxially-oriented arrays of microfibers based on poly(ethylene oxide) (PEO) and CNWs by electrospinning. Compared with the neat PEO fibers, the incorporation of CNWs...

Université de Fribourg

Development of a stimuli-responsive polymer nanocomposite toward biologically optimized, MEMS-based neural probes

Hess, Andreas E. ; Capadona, Jeffrey R. ; Shanmuganathan, Kadhiravan ; Hsu, L. ; Rowan, Suart J. ; Weder, Christoph ; Tyler, D. J. ; Zorman, C. A.

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...

Université de Fribourg

Stress-transfer in anisotropic and environmentally adaptive cellulose whisker nanocomposites

Rusli, Rafeadah ; Shanmuganathan, Kadhiravan ; Rowan, Stuart J. ; Weder, Christoph ; Eichhorn, Stephen J.

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....

Université de Fribourg

Biomimetic mechanically adaptive nanocomposites

Shanmuganathan, Kadhiravan ; Capadona, Jeffrey R. ; Rowan, Stuart J. ; Weder, Christoph

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...

Université de Fribourg

Bio-inspired mechanically-adaptive nanocomposites derived from cotton cellulose whiskers

Shanmuganathan, Kadhiravan ; Capadona, Jeffrey R. ; Rowan, Stuart J. ; Weder, Christoph

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...

Université de Fribourg

Stimuli-responsive mechanically adaptive polymer nanocomposites

Shanmuganathan, Kadhiravan ; Capadona, Jeffrey R. ; Rowan, Stuart J. ; Weder, Christoph

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...