Halloysites nanotubes (HNTs), a naturally occurring and environmental benign clay particles have been successfully functionalized with amphiphilic peptidomimetic polymers, namely polypeptoids by surface-initiated polymerization methods and investigated as emulsion stabilizers towards oil spill remediation. Hydrophilic-lipophilic balance (HLB) can be systematically adjusted by controlling the initial feed ratio of hydrophobic and hydrophilic monomers. The relative HLB of the grafted polypeptoids were shown to affect the wettability of functionalized HNTs and their performance as stabilizers for oil-in-water emulsions. HNTs funtionalized with polypeptoids having appropriate HLB characterisics (HLB = 14.0-16.8) were found to be significantly more effective stabilizers for the oil/water emulsion relative to the pristine HNTs. This is mainly resulted from the enhanced interfacial activities of functionalized HNTs resulting in more effective reduction of interfacial tension and enhanced thermodynamic propensity of the HNT particles to partition at the oil-water interface as well as increased emulsion viscosity. Cell culture studies have revealed that polypeptoids functionalized HNTs are non-cytotoxic towards <i>Alcanivorax borkumensis</i>, a dominant alkane degrading bacterium found in the ocean after oil spill. Notably, in contrast to traditional surfactants which inhibit the oil-degrading bacterial growth, the functionalized HNTs with higher hydrophobic polypeptoid content (HLB = 14.0-16.8) was shown to induce more cell proliferation than those that are less hydrophobic or the pristine HNTs. This study has highlighted the potential of polypeptoid-functionalized natural clay particles as a class of environmentally benign and biocompatible emusifier/stabilizer with tunable surface properties for the oil remendiation application.

Synthesis and investigation of amphiphilic polypeptoid-functionalized halloysite nanotubes (HNTS) as stabilizers towards oil spill remediation

2019 Fall National Meeting

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