不同温度下CL-20/DNDAP共晶形貌的分子动力学模拟

Molecular Dynamics Simulation of CL-20/DNDAP Cocrystal Morphology at Different Temperatures

将六硝基六氮杂异伍兹烷(CL-20)与其他含能材料形成共晶,并使共晶形貌接近球形可以降低其感度。采用附着能(AE)模型和分子动力学(MD)方法预测了不同温度下乙酸甲酯溶剂中的CL-20和2,4-二硝基-2,4-二氮杂戊烷(DNDAP)共晶形貌。同时,计算了溶剂和晶体表面之间的相互作用能,求得晶体表面的附着能,对不同温度下的晶体形貌进行了模拟。结果表明,真空下CL-20/DNDAP共晶体有5个主要生长晶面,(100)面占据相对较大的面积,占比为37.44%,对晶体形貌产生重要影响;CL-20/DNDAP共晶的晶面附着能随着温度的升高而降低,温度升高导致长径比增大,温度为280和360K时的长径比分别为1.80和3.93;较低的温度有利于获得近似球状形貌;理论预测的形貌为斜棱柱且与实验结果吻合良好。

The cocrystallization of hexanitrohexaazoisowuzane(CL-20)with other energetic materials alongside the spheroidization of cocrystal morphology can reduce its sensitivity.The attachment energy(AE)model and molecular dynamics(MD)method were used to predict the morphologies of CL-20 and 2,4-dinitro-2,4-diazapentane(DNDAP)cocrystal in methyl acetate solvent at different temperatures.Meanwhile,the interaction energy between the solvent and the crystal surface was calculated to derive the attachment energy of the crystal surface,and the crystal morphologies at different temperatures were simulated.The results show that there are five morphologically dominant crystal faces of CL-20/DNDAP cocrystal under vacuum.The(100)face occupies a relative large area accounting for 37.44%,which has a significant influence on the crystal morphology.The attachment energy of CL-20/DNDAP cocrystal decreases with the increasing of temperature.The higher temperature leads to an increase in the aspect ratios,which are 1.80 and 3.93 at 280 and 360K,respectively.The lower temperature is beneficial to obtain a nearly spherical morphology.The theoretical predicted morphology of tilted prisms agrees with the experimental result.