10.1021/acs.jpcb.5b07821.s001
Valery V. Prokhorov
Valery V.
Prokhorov
Olga M. Perelygina
Olga M.
Perelygina
Sergey I. Pozin
Sergey I.
Pozin
Eugene
I. Mal’tsev
Eugene
I.
Mal’tsev
Anatoly
V. Vannikov
Anatoly
V.
Vannikov
Polymorphism of Two-Dimensional Cyanine Dye J‑Aggregates
and Its Genesis: Fluorescence Microscopy and Atomic Force Microscopy
Study
American Chemical Society
2015
AFM imaging
monolayer
FOM
strip crystal habits
TC
2015-12-03 00:00:00
Journal contribution
https://acs.figshare.com/articles/journal_contribution/Polymorphism_of_Two_Dimensional_Cyanine_Dye_J_Aggregates_and_Its_Genesis_Fluorescence_Microscopy_and_Atomic_Force_Microscopy_Study/2103586
Polymorphic J-aggregates of monomethine
cyanine dye 3,3′-di(γ-sulfopropyl)-5,5′-dichlorotiamonomethinecyanine
(TC) have been studied by fluorescence optical microscopy (FOM) and
by atomic force microscopy (AFM). The in situ FOM observations in
a solution drop distinguish two J-aggregate morphology classes: flexible
strips and rigid rods. The AFM imaging of dried samples reveals a
strong J-aggregate structural rearrangement under adsorption on a
mica surface with the strips self-folding and the rods squashing into
rectangular bilayers and much deeper destruction. In the present work,
the following structural conclusions have been drawn on the basis
of careful consideration of strip crystal habits and various structural
features of squashed/destructed rods: (1) the tubular morphology of
TC rods is directly proved by FOM measurements in the solution bulk;
(2) the staircase model of molecular arrangement in strips is proposed
explaining the characteristic ∼44° skew angle in strip
vertices; (3) a model of tube formation by a close-packed helical
winding of flexible monolayer strips is proposed and justified which
explains the observed J-aggregate polymorphism and strip-to-rod polymorphic
transformations in a wide spatiotemporal scale; (4) at a nanoscale,
an unexpectedly complex quasi-one-dimensional organization in J-aggregate
two-dimensional monolayers is observed by high-resolution AFM imaging
of constituent nanostrips separated by a characteristic distance in
the range of 6–10 nm. The obtained results indicate that the
underlying monolayer structure is the same for all J-aggregate polymorphs.