Temperature Dependence of Mechanical Properties in Molecular Crystals

Mohamed, Reda M and Mishra, Manish Kumar and Al-Harbi, Laila M and Al-Ghamdi, Mohammed S and Asiri, Abdullah M and Reddy, Chilla Malla and Ramamurty, Upadrasta (2015) Temperature Dependence of Mechanical Properties in Molecular Crystals. In: CRYSTAL GROWTH & DESIGN, 15 (5). pp. 2474-2479.

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Abstract

Quantitative evaluation of the mechanical behavior of molecular materials by a nanoindentation technique has gained prominence recently. However, all the reported data have been on room-temperature properties despite many interesting phenomena observed in them with variations in temperature. In this paper, we report the results of nanoindentation experiments conducted as a function of temperature, T, between 283 and 343 K, on the major faces of three organic crystals: saccharin, sulfathiazole (form 2), and L-alanine, which are distinct in terms of the number and strength of intermolecular interactions in them. Results show that elastic modulus, E, and hardness, H, decrease markedly with increasing T. While E decreases linearly with T, the variations in H with T are not so, and were observed to drop by similar to 50% over the range of T investigated. The slope of the linear fits to E vs T for the organic crystals was found to be around 1, which is considerably higher than the values of 0.3-0.5 reported in the literature for metallic, ionic, and covalently bonded crystalline materials. Possible implications of the observed remarkable changes in H for pharmaceutical manufacturing are highlighted.

Item Type:	Journal Article
Publication:	CRYSTAL GROWTH & DESIGN
Publisher:	AMER CHEMICAL SOC
Additional Information:	Copy right for this article belongs to the AMER CHEMICAL SOC, 1155 16TH ST, NW, WASHINGTON, DC 20036 USA
Department/Centre:	Division of Chemical Sciences > Solid State & Structural Chemistry Unit Division of Mechanical Sciences > Materials Engineering (formerly Metallurgy)
Date Deposited:	16 Jun 2015 04:47
Last Modified:	19 Feb 2019 11:11
URI:	http://eprints.iisc.ac.in/id/eprint/51696

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