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Individual Highlight

Ceramic-Like Thermal Expansion Obtained from Cellulose Nanocrystal Films

Photo of Transmission electron microscope image of cellulose nanocrystals. Robert Moon, USDA Forest ServiceTransmission electron microscope image of cellulose nanocrystals. Robert Moon, USDA Forest ServiceSnapshot : One of the unique properties of cellulose nanocrystals (CNC) are their low dimensional change with changes in temperature. Understanding the role and mechanism associated with thermal expansion within CNCs and CNC composites is important to a variety of fields. Forest Service researchers developed a unique characterization technique using polarized light imaging correlation that allows more accurate coefficient of thermal expansion measurement of thin transparent CNC films.

Principal Investigators(s) :
Moon, Robert J. 
Research Location : Purdue University, University of California
Research Station : Forest Products Laboratory (FPL)
Year : 2013
Highlight ID : 449

Summary

The objective of this research is understanding the role and mechanism associated with thermal expansion within CNCs and CNC composites. The coefficient of thermal expansion (CTE) is important to a variety of fields; for example, electronics where thermal mismatches cause failure of components such as electrodes, and composites where thermal mismatches cause dimensional shape changes. Because CNCs have been used as substrates for electronics and as fillers in composites, accurate determination of CTE of CNCs, CNC composites, and the mechanisms for thermal expansion are important. Researchers have developed a unique characterization technique using polarized light imaging correlation that allows more accurate CTE measurement of thin transparent CNC films. Thin films with 100 percent CNCs have been shown to be metal-like in their CTE (i.e. 25ppm/K). By using shear based casting techniques it is possible to get preferential alignment of the CNCs, and in the direction of CNC alignment it is possible to get ceramic-like CTE (i.e. 9 ppm/K). This was the first study of its kind to use polarized light imaging to measure displacements based on thermal changes.

Forest Service Partners

External Partners

 
  • Purdue University, University of California

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