Size Segregation of Gold Nanoparticles into Bilayer-like Vesicular Assembly

Influence of Solvophobicity of Biphenol-Derived Small Surface Ligands on the Formation of Size-Controllable Gold Nanoparticle Vesicles

“…Ligands with a shorter ethylene glycol segment exhibited lower solubility compared to the longer ethylene glycol segments, resulting in stronger interparticle attraction and the formation of smaller GNVs. Contrary to our previous reports based on SFL and OFBL with an oligo(ethylene glycol) terminus, , the length of the ethylene glycol segment did not affect the size of GNVs, because terminal ethylene glycol did not noticeably impact ligand solubility, thus inducing a similar solvophobic interaction and formation of GNVs with a similar size. Further, in our previously reported SFL, GFL, and CFL, − the solvophobic feature of the fluorinated oligo(ethylene glycol) segment is demonstrated to be crucial for vesicle formation.…”

“…The preparation method for the slice section of GNVs is similar to our previous report . A blend of EPON 812 epoxy resin (2.3 mL), dodecenyl succinic anhydride (1.0 mL), and methylnadic anhydride (1.75 mL) was stirred for 15 min at room temperature.…”

“…In contrast to our previously reported oligo(ethylene glycol)-, glucose-, or carboxylic-acid-terminated fluorinated tetra(ethylene glycol) ligands, respectively, with a flexible fluorinated inner part, the new fluorine-free OBLs with a rigid biphenol fragment exhibited varying solubility in tetrahydrofuran (THF) depending upon the number of terminal ethylene glycol units, demonstrating differential solvophobic effects. In comparison to SFLs and OFBLs possessing a oligo(ethylene glycol) head, , the self-assembly of OBLs and GNPs produced size-controllable GNVs depending upon the unit number of terminal ethylene glycol. The control of the GNV size based on fluorine-free OBLs is superior to that of the conventional fluorinated ligands.…”

“…Another approach for fabricating GNVs is based on small-molecule ligands. − In comparison to multicomplex polymers, small-molecule ligands have a definite, clear structure and molecular weight, making them more suitable for studying the formation mechanism of GNVs by precisely regulating their different fragments. − In a previous study, we reported the formation of vesicles using semi-fluorinated oligo(ethylene glycol) ligand (SFL)-modified GNPs as a result of their solvophobic properties . Furthermore, the oligo(ethylene glycol) head was substituted by glucose, resulting in the generation of a glucose-terminated fluorinated oligo(ethylene glycol) ligand (GFL) .…”

“…However, the corresponding sodium salt ligand generated smaller GNVs compared to CFLs, because the repulsive interaction inhibited the fusion process of GNV formation. Very recently, we reported that an oligo(ethylene glycol)-terminated fluorinated biphenol ligand (OFBL) could self-assemble with binary mixtures of GNPs into size-segregated bilayer-like GNVs because the rigid fluorinated biphenol segment could provide stronger solvophobic attraction than that of flexible fluorinated oligo(ethylene glycol) of SFLs …”