Phase transfer of oleic acid stabilized rod-shaped anatase TiO2 nanocrystals

• Published in: Surface science 2016-06, Vol.648, p.333-338
• Main Authors: Wilkerson, Rachel J., Elder, Theresa, Sowinksi, Olivia, Fostvedt, Jade I., Hoefelmeyer, James D.
• Format: Article
• Language: English
• Subjects: Catechol; Decarboxylation; Ligand exchange; Nanocrystal; Phase transfer; TiO2
• ISSN: 0039-6028; 1879-2758
• DOI: 10.1016/j.susc.2015.10.028

Three methods were evaluated for phase transfer of oleic acid stabilized TiO2 nanorods from non-polar phase to an aqueous phase. Three alkyltrimethylammonium bromide (C6, C8, C12) surfactants were tested and compared with an amphiphilic polymer as interdigitation agents. Ligand substitutions with catechol derivatives with polar functional groups para to the –enediol were evaluated as well. The molecular surfactants were ineffective compared to the amphiphilic polymer in the interdigitation phase transfer approach. Ligand substitution with catechols proceeded efficiently with phase transfer. The ligand substitution reactions were accompanied by gas evolution, which was found to result from decarboxylation of oleic acid in alkaline aqueous conditions. [Display omitted] •Oleic acid stabilized anatase TiO2 nanorods were prepared.•Phase transfer to aqueous phase was studied.•Interdigitation with RN(CH3)3+ was ineffective.•Interdigitation with amphiphilic polymer led to phase transfer with aggregation.•Ligand exchange with polar catechols gave stable aqueous dispersions.•Decarboxylation of oleic acid on the TiO2 nanorods occurred in alkaline aqueous solution.