Halloysites nanotubes (HNTs), a class of naturally occurring aluminosilicate (Al2O3●SiO2●2H2O) clay nanotubes, have emerged as an attractive biocompatible nanomaterials to stabilize oil-in-water emulsions. While it can provide steric barriers between oil drop and water, its ability to reduce the interfacial tension is somewhat limited as compared to conventional surfactants. Formation of small and stable oil-in-water emulsion is important towards bioremediation of oil spills as it provides larger surface areas for oil-degrading bacteria. It is hypothesized that functionalization of HNTs with biocompatible amphipihlic polymers will improve the interfacial activity of HNTs, thus leading to stable emulsion with reduced oil droplet sizes. In this study, amphiphilic polypeptoids, a class of new biocompatible peptidomimetic polymers, was investigated to graft onto the surface of HNTs to manipulate the hydrophilicity-lipophilicity balance (HLB) and biocompatibility of HNTs. By the combined use of multiple characterization techniques, it is found that a variety of polypeptoids can be successfully grafted onto HNTs via the surface-initiated polymerization from HNT external surfaces. Interfacial tension measurements and contact angle studies indicate that the wettability of HNTs can be tuned by adjusting the chemical composition of the polypeptoids. The oil-in-water emulsion stability was further demonstrated to be significantly enhanced through the HNT functionalization with intermediate hydrophobic copolypeptoids. In addition, the polypeptoid functionalized halloysites (f-HNTs) may also stimulate the growth and proliferation of alkane degrading bacterial, A. borkumensis, at the oil-water interface, potentially facilitating the oil-degradation process.

Synthesis and investigation of amphiphilic polypeptoid- functionalized halloysites nanotubes (HNTs) as stabilizer towards oil spill remediation

255th National Meeting (2018)

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