The origin of amphipathic nature of short and thin pristine carbon nanotubes - fully recyclable 1D water-in-oil emulsion stabilizers

CIC nanoGUNE Seminars

Speaker

Karolina Zofia Milowska, Ikerbasque Research Fellow, Theory, CIC nanoGUNE

When

2023/03/27
11:00

Place

nanoGUNE seminar room, Tolosa Hiribidea 76, Donostia - San Sebastian

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**The origin of amphipathic nature of short and thin pristine carbon nanotubes - fully recyclable 1D water-in-oil emulsion stabilizers** Karolina Zofia Milowska Ikerbasque Research Fellow, Theory, CIC nanoGUNE Carbon nanotubes (CNT)s have already demonstrated scientific and technological breakthroughs including scalable coatings, composites, supercapacitors, tissue engineering, and biosensors. However, inconsistencies in understanding of water-solid interfaces for realistic CNTs hamper their individualization- driven functionalities, processability in benign media, and compatibility with a broad-scale of matrices. Pristine CNT processing based on water and inexpensive n-alkanes within a low energy regime would constitute an important step towards greener technologies. Therefore, we quantitatively assess structural CNT components, placing various CNTs on the scale from hydrophobicity to hydrophilicity. This structural interweave can lead to amphipathicity enabling the formation of water-in-oil emulsions. Combining experiments with theoretical studies [1], we comprehensively characterize CNTs and CNT emulsions establishing descriptors of the emulsifying behavior of pristine and purified CNTs. They emerge as having hydrophilic open-ends, small number of oxygen-functionalized/vacancy surface areas, and hydrophobic sidewalls and full caps. The interplay of these regions allows short and thin CNTs to be utilized as fully recyclable 1D surfactants stabilizing water/oil emulsions which, as we demonstrate, can be applied as paints for flexible conductive coatings. These coatings are characterized by considerable smaller resistance than coatings with additional surfactants or containing pristine graphene. In addition, we show how the amphipathic strength depends on CNT size, the pristine-to-oxidized/vacancy domains and the oil-to-water ratios. Our results confirm shorter and thinner pristine multi-walled CNTs as promising candidates for fully recyclable 1D emulsifying agents capable of replacing aquatoxic low-molecular surfactants in the the preparation of composites, in/as heat transfer (io)nanofluids, superlubricants, paints, coatings, electrocatalysts and as drug vehicles for locoregional therapy or contrast agents in bioimaging.