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CARBONLETT, vol. 24, no. 1, pp.90-96, 2017

DOI: http://dx.doi.org/:10.5714/CL.2017.24.090

Optical sensitivity of DNA-dispersed single-walled carbon nanotubes within cement composites under mechanical load

Jin Hee Kim1, Inkyu Rhee2,♠, Yong Chae Jung3, Sumin Ha4 and Yoong Ahm Kim4,♠

Affiliation: 1Faculty of Engineering, Chonnam National University, Gwangju 61186, Korea
2Department of Civil Engineering, Chonnam National University, Gwangju 61186, Korea
3Multifunctional Structural Composite Research Center, Institute of Advanced Composite Materials, Korea Institute of Science and Technology (KIST), Jeonbuk 55324, Korea
4School of Polymer Science and Engineering, Department of Polymer Engineering, Graduate School & Alan G. MacDiarmid Energy Research Institute, Chonnam National University, Gwangju 61186, Korea

Abstract: We demonstrated the sensitivity of optically active single-walled carbon nanotubes (SWCNTs) with a diameter below 1 nm that were homogeneously dispersed in cement composites under a mechanical load. Deoxyribonucleic acid (DNA) was selected as the dispersing agent to achieve a homogeneous dispersion of SWCNTs in an aqueous solution, and the dispersion state of the SWCNTs were characterized using various optical tools. It was found that the addition of a large amount of DNA prohibited the structural evolution of calcium hydroxide and calcium silicate hydrate. Based on the in-situ Raman and X-ray diffraction studies, it was evident that hydrophilic functional groups within the DNA strongly retarded the hydration reaction. The optimum amount of DNA with respect to the cement was found to be 0.05 wt%. The strong Raman signals coming from the SWCNTs entrapped in the cement composites enabled us to understand their dispersion state within the cement as well as their interfacial interaction. The G and G’ bands of the SWCNTs sensitively varied under mechanical compression. Our results indicate that an extremely small amount of SWCNTs can be used as an optical strain sensor if they are homogeneously dispersed within cement composites.

Keyword: cement composite, single walled carbon nanotube, DNA, compressive strength, Raman