Additive-controlled crystallization is becoming an increasingly significant approach to controlling crystal morphology. In this study, to better understand the influence mechanism of additive on crystal morphology, 4-(hydroxymethyl) benzoic acid (p-HMBA) crystal crystallization behaviors with poly(vinylpyrrolidone) (PVP) were investigated by combing experiments and molecular simulations. Morphology of p-HMBA was modified from rod to block in the presence of PVP. It was seen that PVP would impede the crystal nucleation and growth. The inhibition effect of PVP on axial direction growth was much stronger than that on the radial direction. Molecular dynamics simulations revealed that the nucleation rate of p-HMBA crystal was inhibited due to the hydrogen-bonding interaction between PVP and p-HMBA molecules. The stronger interaction energy between PVP molecules and the (1 0 1̅) surface than that of the (0 1 0) surface might cause a stronger inhibition effect of PVP on the axial direction, which leads to the decline of the crystal aspect ratio.

中文翻译：

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揭示添加剂在改变 4-（羟甲基）苯甲酸结晶行为中的作用

添加剂控制结晶正成为控制晶体形态的一种越来越重要的方法。本研究为更好地了解添加剂对晶体形貌的影响机理，结合实验和分子模拟研究了4-(羟甲基)苯甲酸( p -HMBA)与聚乙烯吡咯烷酮(PVP)的结晶行为。在 PVP 存在下， p -HMBA 的形态从棒状改变为块状。可以看出，PVP 会阻碍晶体的成核和生长。PVP对轴向生长的抑制作用远强于径向。分子动力学模拟表明p的成核率由于PVP和p -HMBA分子之间的氢键相互作用，抑制了-HMBA晶体。PVP分子与(1 0 1̅)表面的相互作用能比(0 1 0)表面的相互作用能强，可能导致PVP对轴向的抑制作用更强，从而导致晶体纵横比下降。