Department of Chemical and Materials Engineering, Tamkang University, No. 151, Yingzhuan Rd., Tamsui Dist., New Taipei City 25137, Taiwan.
Soft Matter. 2017 May 3;13(17):3107-3115. doi: 10.1039/c6sm02853e.
Molecular interactions, rheological behaviors and microstructures of 1,3:2,4-dibenzylidene-d-sorbitol (DBS)/poly(ethylene glycol) (PEG) organogel-inorganic silica hybrid materials are discussed in this study. DBS can dissolve in low-molecular-weight PEG to form organogels. The self-assembly behavior of these organogels was significantly influenced by the addition of the inorganic silica. The π interactions between the phenyl rings of DBS were not influenced by silica addition; however, the addition of silica affected the intermolecular hydrogen bonding of DBS, which interacts with PEG. The silica more likely interacted with PEG and decreased the intermolecular interactions between DBS and PEG, which resulted in an increase in the self-assembly of DBS. Therefore, the gel formation time and gel dissolution temperature increased as the amount of silica increased, as determined by dynamic rheological instruments. In addition, these organogel systems were all found to exhibit spherulite-like textures under polarized optical microscopy. The addition of silica and the increased DBS self-assembly in PEG resulted in a higher self-assembly temperature of the organogels. The higher temperature resulted in the presence of fewer nucleation sites and larger spherulite sizes in these systems. Small-angle X-ray scattering results demonstrated lamellar packing in these spherulite-like morphologies. Furthermore, the organogels with silica affected the intermolecular hydrogen bonding between DBS and PEG to facilitate the self-assembly of DBS, which resulted in increased diameter sizes of the DBS nanofibrils, as observed using scanning electron microscopy. It was observed that the silica was entrapped within these nanofibrillar networks.
本文讨论了 1,3:2,4-二亚苄基-d-山梨糖醇（DBS）/聚乙二醇（PEG）有机凝胶-无机二氧化硅杂化材料的分子相互作用、流变行为和微观结构。DBS 可溶解于低分子量的 PEG 中形成有机凝胶。这些有机凝胶的自组装行为受无机二氧化硅的添加显著影响。DBS 中苯环之间的π 相互作用不受二氧化硅添加的影响；然而，二氧化硅的添加影响了 DBS 的分子间氢键，其与 PEG 相互作用。二氧化硅更可能与 PEG 相互作用，减少 DBS 和 PEG 之间的分子间相互作用，从而导致 DBS 的自组装增加。因此，通过动态流变仪确定，凝胶形成时间和凝胶溶解温度随着二氧化硅添加量的增加而增加。此外，这些有机凝胶体系在偏光显微镜下均呈现出类似球晶的纹理。二氧化硅的添加和 PEG 中 DBS 自组装的增加导致有机凝胶的自组装温度升高。较高的温度导致这些体系中较少的成核点和较大的球晶尺寸。小角 X 射线散射结果表明这些类似球晶的形态中存在层状堆积。此外，含有二氧化硅的有机凝胶影响 DBS 和 PEG 之间的分子间氢键，促进 DBS 的自组装，从而导致 DBS 纳米纤维的直径增大，这可通过扫描电子显微镜观察到。观察到二氧化硅被包埋在这些纳米纤维网络中。
