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Photoreactions and lateral patterning in Langmuir and Langmuir–Blodgett films
Author(s) -
Matsumoto Mutsuyoshi
Publication year - 2007
Publication title -
the chemical record
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.61
H-Index - 78
eISSN - 1528-0691
pISSN - 1527-8999
DOI - 10.1002/tcr.20099
Subject(s) - photoisomerization , azobenzene , langmuir–blodgett film , monolayer , chemistry , molecule , photochemistry , chemical engineering , chromophore , langmuir , j aggregate , materials science , nanotechnology , isomerization , adsorption , organic chemistry , catalysis , engineering
Abstract Reversible morphological changes occur with photoisomerization of azobenzene in Langmuir–Blodgett (LB) films complexed with polycations, which contradicts an implicit assumption of the concept of free volume that two‐dimensional film structures are preserved during the photoisomerization. J‐aggregates of chromophores are formed by two processes. The first process is “light‐induced J‐aggregation” in which photoisomerized molecules form J‐aggregates. The other process is “triggered J‐aggregation,” in which photoisomerization of one of the components triggers J‐aggregation of another chemical species in the mixed films. Both processes of J‐aggregation are in many cases accompanied by large morphological changes of the films. However, LB films fabricated using processes under isobaric conditions do not change their morphology during light‐induced J‐aggregation and are patterned with J‐aggregates using ultraviolet illumination through a photomask. Phase separation in mixed LB films gives rise to two‐dimensional patterns, which are used to fabricate templates by using an amphiphilic silane‐coupling agent as one of the components in the mixed LB films. Nanopatterns are also fabricated. © 2007 The Japan Chemical Journal Forum and Wiley Periodicals, Inc. Chem Rec 7: 69–77; 2007: Published online in Wiley InterScience ( www.interscience.wiley.com ) DOI 10.1002/tcr.20099