Hierarchical inorganic nanopatterning (INP) through direct easy block-copolymer templating

Abstract

We introduce a simple route towards hierarchical TiO₂ nanopatterns using a block-copolymer template approach combined with a dip-coating process and soft inorganic chemistry. The bimodal characteristic is associated to the preparation of solutions that contain two distinct populations of micelles PB-b-PEO (with the same chemical nature but different sizes) that do not mix or aggregate. The relative quantity of each population can be precisely adjusted in the initial solution composition by mixing the corresponding proportion of parent solutions, and is recovered in the final TiO₂ nanopattern. The latter hierarchical nanopatterning exhibits homogeneous distribution of 2 distinct sizes of nanoperforations in relation to the presence of both micelles. We show that the bimodal micellar solution is stable for more than four weeks at RT, revealing an unexpected dynamic stability. We believe that the resulting nanopatterns could be useful for investigating the behaviour of block copolymer micelles in solutions. The present study is mainly supported by DLS and AFM analyses.