Anisotropic Optical Properties and Structures of Block Copolymer/Silica Thin Films Containing Aligned Porphyrin J-Aggregates
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- 作者：Christian A. Steinbeck ; Matthias Ernst ; Beat H. Meier ; Bradley F. Chmelka
- 刊名：Journal of Physical Chemistry C
- 出版年：2008
- 出版时间：February 21, 2008
- 年：2008
- 卷：112
- 期：7
- 页码：2565 - 2573
- 全文大小：332K
- 年卷期：v.112,no.7(February 21, 2008)
- ISSN：1932-7455
文摘
Mesostructured silica-block copolymer thin films are demonstrated to provide orientationally ordered hostmatrixes for stable alignment of coassembled porphyrin J-aggregates with anisotropic optical properties. Visiblelight at 490 nm was absorbed anisotropically (A
/A
= 1.35) by aligned, hexagonally ordered (ethyleneoxide)20-(propylene oxide)70-(ethylene oxide)20 (P123) triblock copolymer/silica nanocomposite filmscontaining 1-5 wt % tetrakis(4-sulfonatophenyl)porphyrin (TPPS4) guest species in the form of J-aggregates.Amorphous silica prepared similarly and containing TPPS4 J-aggregates, but without structure-directing blockcopolymer species, absorbed light isotropically (A/A = 1.00). The porphyrin guest species were determinedto be preferentially associated with the hydrophilic ethylene oxide moieties of the triblock copolymer, byusing two-dimensional (2D) solid-state 1H{1H} and 13C{1H} NMR correlation experiments, including underconditions of fast (45 kHz) magic-angle spinning. Interrelationships are shown and established among synthesisconditions, the molecular, mesoscopic, and orientational structural ordering in the porphyrin-containingnanocomposite thin films, and their macroscopic optical properties.
/A = 1.35) by aligned, hexagonally ordered (ethyleneoxide)20-(propylene oxide)70-(ethylene oxide)20 (P123) triblock copolymer/silica nanocomposite filmscontaining 1-5 wt % tetrakis(4-sulfonatophenyl)porphyrin (TPPS4) guest species in the form of J-aggregates.Amorphous silica prepared similarly and containing TPPS4 J-aggregates, but without structure-directing blockcopolymer species, absorbed light isotropically (A/A = 1.00). The porphyrin guest species were determinedto be preferentially associated with the hydrophilic ethylene oxide moieties of the triblock copolymer, byusing two-dimensional (2D) solid-state 1H{1H} and 13C{1H} NMR correlation experiments, including underconditions of fast (45 kHz) magic-angle spinning. Interrelationships are shown and established among synthesisconditions, the molecular, mesoscopic, and orientational structural ordering in the porphyrin-containingnanocomposite thin films, and their macroscopic optical properties.