Self-assembly microstructures of amphiphilic polyborate in aqueous solutions

A new type of amphiphilic homo-polyborate was synthesized with the surface tension (γCMC) in deionized water 31.2 mN m−1 (pH = 7, 25 °C), which is similar to low-molecule surfactants. Self-assembly behaviors of the polyborate in aqueous solutions were investigated by TEM. Self-aggregation morphologies of the polyborate can be controlled by the concentration of NaCl. With the increase of the concentration of NaCl, micromorphologies from the amphiphilic polyborate transformed from spherical polymeric vesicles to tree-like or even vertebra-like morphologies. It was also found that, the polymeric vesicles show a strong stability against ethanol addition, even when the concentration of ethanol increases to a volume ratio of 33%, they still maintain good micromorphologies. A possible mechanism of vesicle formation was proposed based on packing parameter theory.