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New Triblock Copolymer Templates, PEO‐PB‐PEO, for the Synthesis of Titania Films with Controlled Mesopore Size, Wall Thickness, and Bimodal Porosity
Author(s) -
Ortel Erik,
Fischer Anna,
Chuenchom Laemthong,
Polte Jörg,
Emmerling Franziska,
Smarsly Bernd,
Kraehnert Ralph
Publication year - 2012
Publication title -
small
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.785
H-Index - 236
eISSN - 1613-6829
pISSN - 1613-6810
DOI - 10.1002/smll.201101520
Subject(s) - materials science , mesoporous material , copolymer , polymer , chemical engineering , micelle , ethylene oxide , porosity , oxide , propylene oxide , evaporation , polymer chemistry , composite material , organic chemistry , catalysis , chemistry , thermodynamics , physics , aqueous solution , engineering , metallurgy
The synthesis and properties of a series of new structure‐directing triblock copolymers with PEO‐PB‐PEO structure (PEO = poly(ethylene oxide) and PB = polybutadiene) and their application as superior pore‐templates for the preparation of mesoporous titania coatings are reported. Starting from either TiCl 4 or from preformed TiO 2 nanocrystalline building blocks, mesoporous crystalline titanium oxide films with a significant degree of mesoscopic ordered pores are derived, and the pore size can be controlled by the molecular mass of the template polymer. Moreover, the triblock copolymers form stable micelles already at very low concentration, i.e., prior to solvent evaporation during the evaporation‐induced self‐assembly process (EISA). Consequently, the thickness of pore walls can be controlled independently of pore size by changing the polymer‐to‐precursor ratio. Thus, unprecedented control of wall thickness in the structure of mesoporous oxide coatings is achieved. In addition, the micelle formation of the new template polymers is sufficiently distinct from that of typical commercial PPO‐PEO‐PPO polymers (Pluronics; PPO = poly(propylene oxide)), so that a combination of both polymers facilitates bimodal porosity via dual micelle templating.