A Vapor Phase Hydrothermal Modification Method Converting a Honeycomb Structured Hybrid Film into Photoactive TiO₂ Film

Abstract

Transforming an organic/inorganic hybrid material into a pure inorganic material without losing its original structure is of interest for a range of applications. In this work, a simple and effective vapor phase hydrothermal method was developed to transform a 3D honeycomb structured PS/TTIP hybrid film into a photoactive TiO2 film without dismantling the originally templated 3D structure. The method utilizes the vapor phase hydrothermal process to create titania network/clusters with sufficient mechanical strength via the formation of Ti-oxo bridges. The organic components of the sample can be removed by means of pyrolysis while perfectly maintaining the original 3D honeycomb structure. The resultant film can be directly used for photocatalysis applications and could be further modified for other applications. In principle, this method can be used to preserve 3D structures of other organic/inorganic hybrid films during their conversion to pure inorganic films via a pyrolysis process, if mechanically strong networks can be formed as a result of hydrolysis reactions. The ability to preserve the preferred 3D structure during the subsequent conversion processes enables realization of the full benefit of unique architectures created by a templating method.

Breath Figure: A Nature-Inspired Preparation Method for Ordered Porous Films

“…463 To do this, the particles of the inorganic materials or their precursors should be incorporated into the BFA films. After removing the polymer components by pyrolysis, inorganic BFA films are obtained.…”

Advances in Fabrication Materials of Honeycomb Structure Films by the Breath-Figure Method

“…Zhao et al . used the same process to introduce a honeycomb structured hybrid film into inorganic photoactive TiO 2 film [111]. In their study, a solution of PS with titanium tetraisopropoxide (TTIP) as TiO 2 precursor was prepared.…”

“…They demonstrated a simple and effective vapor phase hydrothermal modification method (calcination at 550 °C for 2 h) which is capable of transforming a honeycomb structured hybrid film into a photoactive TiO 2 film without dismantling the originally templated three-dimensional structure (Figure 10). The preservation of the organic/inorganic hybrid film structure during its conversion to pure inorganic film by means of pyrolysis was ensured further [111]. …”

Ordered meso-/macroporous silica and titania films by breath figure templating in combination with non-hydrolytic sol–gel processing

“…Chen et al [8] synthesized e.g. porous organiceinorganic hybrid films by applying the BF method with a gelable block copolymer, whereas Zhao et al [9] developed a hydrothermal method for the transformation of a BF honeycomb structure into a photoactive TiO 2 film. In all cases, the humidity during the preparation of the films had to be controlled carefully.…”