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Morphology Transition in Ultrathin Titania Films: From Pores to Lamellae
Author(s) -
Cheng YaJun,
Zhou Shaoying,
Gutmann Jochen S.
Publication year - 2007
Publication title -
macromolecular rapid communications
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.348
H-Index - 154
eISSN - 1521-3927
pISSN - 1022-1336
DOI - 10.1002/marc.200700165
Subject(s) - copolymer , morphology (biology) , materials science , chemical engineering , amphiphile , mesoporous material , solvent , photoluminescence , sol gel , polymer chemistry , nanotechnology , composite material , organic chemistry , chemistry , polymer , catalysis , genetics , optoelectronics , engineering , biology
Nanostructured TiO 2 thin films were prepared using an amphiphilic PS‐ b ‐PEO block copolymer as a templating agent. A good–poor solvent pair‐induced pair phase separation process was coupled with sol–gel chemistry to control the morphology of the TiO 2 film in a solution of 1,4‐dioxane, concentrated HCl, and titanium tetraisopropoxide (TTIP). By varying the block copolymer concentration from 0.25 to 4.0 wt.‐% while keeping the relative ratios among 1,4‐dioxane, conc. HCl, and TTIP constant, a morphology transition from pores to lamellae was observed. The photoluminescence (PL) properties of the film composed of different morphologies were studied, and the PL properties were found to be independent of the morphologies of the mesoporous films. The mechanism of the morphology evolution with respect to the copolymer concentration is further discussed.