Tailoring the stability/aggregation of one-dimensional TiO2(B)/titanate nanowires using surfactants

Atiđa Selmani; Johannes Lützenkirchen; Kristina Kučanda; Dario Dabić; Engelbert Redel; Ida Delač Marion; Damir Kralj; Darija Domazet Jurašin; Maja Dutour Sikirić

doi:10.3762/bjnano.10.103

Tailoring the stability/aggregation of one-dimensional TiO₂(B)/titanate nanowires using surfactants

Beilstein J Nanotechnol. 2019 May 13:10:1024-1037. doi: 10.3762/bjnano.10.103. eCollection 2019.

Authors

Affiliations

¹ Laboratory for Biocolloids and Surface Chemistry, Division of Physical Chemistry, Ruđer Bošković Institute, Bijenička Cesta 54, 10000 Zagreb, Croatia.
² Karlsruhe Institute of Technology (KIT), Institute for Nuclear Waste Disposal, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany.
³ Department of Chemistry, Faculty of Science, University of Zagreb, Horvatovac 102a, 10002 Zagreb, Croatia.
⁴ current affiliation: Department of Organic Chemistry, Weizmann Institute of Science, Rehovot 76100, Israel.
⁵ current affiliation: Department of Analytical Chemistry, Faculty of Chemical Engineering and Technology, Marulićev trg 19, 10000 Zagreb, Croatia.
⁶ Karlsruhe Institute of Technology (KIT), Institute of Functional Interfaces (IFG), Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany.
⁷ Center of Excellence for Advanced Materials and Sensing Devices, Institute of Physics, Bijenička 46, 10000 Zagreb, Croatia.
⁸ Laboratory for Precipitation Processes, Division of Materials Chemistry, Ruđer Bošković Institute, Bijenička Cesta 54, 10000 Zagreb, Croatia.

Abstract

The increased utilization of one-dimensional (1D) TiO₂ and titanate nanowires (TNWs) in various applications was the motivation behind studying their stability in this work, given that stability greatly influences both the success of the application and the environmental impact. Due to their high abundance in aqueous environments and their rich technological applicability, surfactants are among the most interesting compounds used for tailoring the stability. The aim of this paper is to determine the influence of surfactant molecular structure on TNW stability/aggregation behavior in water and aqueous NaBr solution by dynamic and electrophoretic light scattering. To accomplish this, two structurally different quaternary ammonium surfactants (monomeric DTAB and the corresponding dimeric 12-2-12) at monomer and micellar concentrations were used to investigate TNW stability in water and NaBr. It was shown that TNWs are relatively stable in Milli-Q water. However, the addition of NaBr induces aggregation, especially as the TNW mass concentration increases. DTAB and 12-2-12 adsorb on TNW surfaces as a result of the superposition of favorable electrostatic and hydrophobic interactions. As expected, the interaction of TNWs with 12-2-12 was stronger than with DTAB, due to the presence of two positively charged head groups and two hydrophobic tails. As a consequence of the higher adsorption of 12-2-12, TNWs remained stable in both media, while DTAB showed an opposite behavior. In order to gain more insight into changes in the surface properties after surfactant adsorption on the TNW surface, a surface complexation model was employed. With this first attempt to quantify the contribution of the surfactant structure on the adsorption equilibrium according to the observed differences in the intrinsic log K values, it was shown that 12-2-12 interacts more strongly with TNWs than DTAB. The modelling results enable a better understanding of the interaction between TNWs and surfactants as well as the prediction of the conditions that can promote stabilization or aggregation.

Keywords: 1D nanomaterials; cationic surfactants; stability; surface complexation model; titanate nanowires.