Controllable synthesis of tunable aspect ratios novel h-BN nanorods with an enhanced wetting performance for water repellent applications

Abstract

One dimensional (1-D) nanostructured layer with tunable aspect ratio holds the prodigious potential for achieving smart surfaces with controlled wettability. Herein, a simple and cost-effective technique was employed to develop the high quality and novel hexagonal boron nitride (h-BN) nanorods. These h-BN nanorods (BNNRs) with tunable aspect ratio contained oriented aligned nanoparticles along the [0001] direction were prepared by wet chemical reaction method using non-toxic precursor (melamine, urea and boric acid). Controlled chemical reactions in applied atmosphere (Ar 90% + NH3 10%) play an important role to transform the morphological growth and tune the aspect ratio (AR) of h-BN nanorods by simply varying the annealing temperature (1100–1300 ◦C). The correlation between structural, morphological and wetting properties of prepared materials were also investigated in detail. The behavior of wettability was also analyzed in term of water contact angle and surface free energy using two complex models, Wu and Owens & Wendt. Overall, the effect of annealing temperature and atmosphere were accountable to trigger the growth (aspect ratio from ~2.5 to ~5.2) and wetting behavior from hydrophobic to ~ super hydrophobic (contact angle from 127◦ to 145◦.). Produced at 1300 ◦C, the highly oriented h-BN nanorods with large aspect ratio (AR) ~5.2 and excellent wettability (hydrophobicity ~145◦) may be a promising candidate for water repellent applications.