Almehairbi Mubarak, Joshi Vikram C, Irfan Ahamad, Saeed Zeinab M, Alkhidir Tamador, Abdelhaq Aya M, Managutti Praveen B, Dhokale Bhausaheb, Jadhav Thaksen, Calvin Sun Changquan, Mohamed Sharmarke
Department of Chemistry, Green Chemistry & Materials Modelling Laboratory, Khalifa University of Science and Technology, P.O. Box, 127788, Abu Dhabi, UAE.
Pharmaceutical Materials Science and Engineering Laboratory, Department of Pharmaceutics, College of Pharmacy, University of Minnesota, Minneapolis, Minnesota, 55455, USA.
Chemistry. 2024 Jul 5;30(38):e202400779. doi: 10.1002/chem.202400779. Epub 2024 May 24.
Dynamic molecular crystals are an emerging class of crystalline materials that can respond to mechanical stress by dissipating internal strain in a number of ways. Given the serendipitous nature of the discovery of such crystals, progress in the field requires advances in computational methods for the accurate and high-throughput computation of the nanomechanical properties of crystals on specific facets which are exposed to mechanical stress. Here, we develop and apply a new atomistic model for computing the surface elastic moduli of crystals on any set of facets of interest using dispersion-corrected density functional theory (DFT-D) methods. The model was benchmarked against a total of 24 reported nanoindentation measurements from a diverse set of molecular crystals and was found to be generally reliable. Using only the experimental crystal structure of the dietary supplement, L-aspartic acid, the model was subsequently applied under blind test conditions, to correctly predict the growth morphology, facet and nanomechanical properties of L-aspartic acid to within the accuracy of the measured elastic stiffness of the crystal, 24.53±0.56 GPa. This work paves the way for the computational design and experimental realization of other functional molecular crystals with tailor-made mechanical properties.
动态分子晶体是一类新兴的晶体材料，它能够通过多种方式耗散内部应变来响应机械应力。鉴于此类晶体发现的偶然性，该领域的进展需要计算方法的进步，以便准确且高通量地计算暴露于机械应力下特定晶面上晶体的纳米力学性质。在此，我们开发并应用了一种新的原子模型，使用色散校正密度泛函理论（DFT-D）方法来计算任何感兴趣晶面上晶体的表面弹性模量。该模型以来自不同分子晶体的总共24次报道的纳米压痕测量为基准进行测试，结果发现其总体可靠。仅使用膳食补充剂L-天冬氨酸的实验晶体结构，该模型随后在盲测条件下应用，以在晶体测量弹性刚度（24.53±0.56 GPa）的精度范围内正确预测L-天冬氨酸的生长形态、晶面和纳米力学性质。这项工作为具有定制机械性能的其他功能分子晶体的计算设计和实验实现铺平了道路。
