Thermal expansion of self-organized and shear-oriented cellulose nanocrystal films

Jairo A. Diaz, Xiawa Wu, Ashlie Martini, Jeffrey P. Youngblood, Robert J. Moon

Research output: Contribution to journalArticlepeer-review

88 Scopus citations

Abstract

The coefficient of thermal expansion (CTE) of cellulose nanocrystal (CNC) films was characterized using novel experimental techniques complemented by molecular simulations. The characteristic birefringence exhibited by CNC films was utilized to calculate the in-plane CTE of self-organized and shear-oriented self-standing CNC films from room temperature to 100 C using polarized light image correlation. CNC alignment was estimated via Hermans order parameter (S) from 2D X-ray diffraction measurements. We found that films with no preferential CNC orientation through the thickness (S: ∼ 0.0) exhibited an isotropic CTE (∼25 ppm/K). In contrast, films with aligned CNC orientations (S: ∼0.4 to 0.8) had an anisotropic CTE response: For the highest CNC alignment (S: 0.8), the CTE parallel to CNC alignment was ∼9 ppm/K, while that perpendicular to CNC alignment was ∼158 ppm/K. CNC film thermal expansion was proposed to be due primarily to single crystal expansion and CNC-CNC interfacial motion. The relative contributions of inter- and intracrystal responses to heating were explored using molecular dynamics simulations.

Original languageEnglish (US)
Pages (from-to)2900-2908
Number of pages9
JournalBiomacromolecules
Volume14
Issue number8
DOIs
StatePublished - Aug 12 2013

All Science Journal Classification (ASJC) codes

  • Bioengineering
  • Biomaterials
  • Polymers and Plastics
  • Materials Chemistry

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