Klitou Panayiotis, Rosbottom Ian, Karde Vikram, Heng Jerry Y Y, Simone Elena
School of Food Science and Nutrition, Food Colloids and Bioprocessing Group, University of Leeds, Woodhouse Ln., Woodhouse, LeedsLS2 9JT, United Kingdom.
Department of Chemical Engineering, Imperial College London, Imperial College Rd, South Kensington, LondonSW7 2AZ, United Kingdom.
Cryst Growth Des. 2022 Oct 5;22(10):6103-6113. doi: 10.1021/acs.cgd.2c00707. Epub 2022 Sep 19.
The surface energy and surface chemistry of a crystal are of great importance when designing particles for a specific application, as these will impact both downstream manufacturing processes as well as final product quality. In this work, the surface properties of two different quercetin solvates (quercetin dihydrate and quercetin DMSO solvate) were studied using molecular (synthonic) modeling and experimental techniques, including inverse gas chromatography (IGC) and contact angle measurements, to establish a relationship between crystal structure and surface properties. The attachment energy model was used to predict morphologies and calculate surface properties through the study of their growth synthons. The modeling results confirmed the surface chemistry anisotropy for the two forms. For quercetin dihydrate, the {010} facets were found to grow mainly by nonpolar offset quercetin-quercetin stacking interactions, thus being hydrophobic, while the {100} facets were expected to be hydrophilic, growing by a polar quercetin-water hydrogen bond. For QDMSO, the dominant facet {002} grows by a strong polar quercetin-quercetin hydrogen bonding interaction, while the second most dominant facet {011} grows by nonpolar π-π stacking interactions. Water contact angle measurements and IGC confirmed a greater overall surface hydrophilicity for QDMSO compared to QDH and demonstrated surface energy heterogeneity for both structures. This work shows how synthonic modeling can help in the prediction of the surface nature of crystalline particles and guide the choice of parameters that will determine the optimal crystal form and final morphology for targeted surface properties, for example, the choice of crystallization conditions, choice of solvent, or presence of additives or impurities, which can direct the crystallization of a specific crystal form or crystal shape.
在为特定应用设计颗粒时，晶体的表面能和表面化学非常重要，因为它们会影响下游制造工艺以及最终产品质量。在这项工作中，使用分子（合成子）建模和实验技术，包括反相气相色谱（IGC）和接触角测量，研究了两种不同槲皮素溶剂化物（槲皮素二水合物和槲皮素二甲基亚砜溶剂化物）的表面性质，以建立晶体结构与表面性质之间的关系。通过研究它们的生长合成子，使用附着能模型来预测形态并计算表面性质。建模结果证实了这两种形式的表面化学各向异性。对于槲皮素二水合物，发现{010}晶面主要通过非极性的槲皮素 - 槲皮素错位堆积相互作用生长，因此是疏水的，而{100}晶面预计是亲水的，通过极性的槲皮素 - 水氢键生长。对于槲皮素二甲基亚砜溶剂化物，主要晶面{002}通过强极性的槲皮素 -槲皮素氢键相互作用生长，而第二主要晶面{011}通过非极性的π - π堆积相互作用生长。水接触角测量和IGC证实，与槲皮素二水合物相比，槲皮素二甲基亚砜溶剂化物的整体表面亲水性更强，并证明了两种结构的表面能不均匀性。这项工作展示了合成子建模如何有助于预测晶体颗粒的表面性质，并指导确定目标表面性质的最佳晶体形式和最终形态的参数选择，例如结晶条件的选择、溶剂的选择或添加剂或杂质的存在，这些可以引导特定晶体形式或晶体形状的结晶过程。
