Construction And Interfacial Behavior Study Of Pentacyclic Triterpenoid-based Amphiphilic Molecules

Interface behavior exists widely in our daily life,for example,solid-liquid interface behavior of droplets impacting solid surfaces;liquid-liquid interface behavior at water/oil interface in emulsion.Interface behavior is especially widely used in agricultural production,such as pesticide spraying,release,retention,etc.Using the special structure of amphiphilic molecules to construct assemblies with excellent performance and realize the regulation of interface behavior is of great significance in the field of agriculture.In our paper,two kinds of glycyrrhetic acid-based amphiphilic small molecules were constructed by using the natural product glycyrrhetinic acid,because glycyrrhetinic acid has the hydrophobic framework,active sites and chiral centers.The author explored the self-assembly process of amphiphilic small molecules in aqueous solution or at the water-oil interface,and the effect of their assembly on the behavior of the solid-liquid or liquid-liquid interfaces.The main research results are as follows:1.A amphiphilic methyl glycyrrhetinate-pyridine salt(MGP)was prepared by linking hydrophilic pyridine salt to hydrophobic glycyrrhetinic acid framework by esterification reaction.It was found that the chiral transfer and amplification from natural triterpenoid to supramolecular chirality was realized through molecular self-assembly.Physical entanglement between the chiral helical ribbons and the hydrophobic surface micro/nano structure can inhibit droplet rebound.This work proposes a strategy to utilize supramolecular assemblies to suppress droplet bouncing.2.Using the amphiphilic structure of the glycyrrhetic acid-disaccharide molecule,an ordered arrangement can be formed at the water-oil interface.And the interfacial jamming behavior of emulsion droplets is observed,resulting in a shrinking film.It is interesting that an interfacial film with a certain mechanical strength can be obtained by a single component and its aqueous solution concentration is less than the critical micelle concentration.In addition,the arrangement model of amphiphilic molecules at the water/oil interface was deduced by calculating the adsorption capacity and molecular cross-sectional area.