Photoresponsive materials play an
important role in smart sensors
and readable optical devices. The α-cyanostilbene moiety gathers Z/E-isomerization, mesogenic, and aggregation-induced
enhanced emission (AIEE) properties together and can be considered
as a multifunctional building block bearing luminogen, AIEgen, mesogen,
and chromphore characteristics. Here, we report isomerization induced
a series of notable reversible switching based on α-cyanostilbene
containing hydrogen-bonded supramolecular polymers. Z- and E-stereoisomers of dendritic α-cyanostilbene
derivatives (Z-CNBP and E-CNBP)
were hydrogen-bonded with poly(4-vinylpyridine) (P4VP), giving rise
to P4VP(Z-CNBP)
x
and
P4VP(E-CNBP)
x
. P4VP(Z-CNBP)
x
exhibit a hexagonal
columnar (Φh) phase at 0.4 ≤ x ≤ 1.0, while the lamellar phase could be formed for P4VP(E-CNBP)
x
at 0.3 ≤ x ≤ 0.7. P4VP(Z-CNBP)0.8 shows photothermal E/Z-isomerization
induced reversible switching, including phase structures, surface
topographies, birefringence, and fluorescence properties, whereas
P4VP(E-CNBP)0.5 exhibits enhanced fluorescence
emission upon UV irradiation.
Polymer
structures with tunable symmetry and sizes are desired
for applications such as lithography, filtration membranes, and separation.
Here we report the self-assembled supramolecular hexagonal columnar
(ΦH) structures with tunable lattice size varying
from 5 to 7 nm by constructing hydrogen-bonded copolymers bearing
poly(4-vinylpyridine) (P4VP) and two dendritic molecular additives,
1-[4′-(3″,4″,5″-tridecyloxybenzoyloxy)phenyleneoxycarbonyl]-3-[(4″-hydroxyphenyl)oxycarbonyl]benzene
(12CBP) and 4-hydroxyphenyl (3,4,5-tridecyloxy)benzoate (12CTB). Despite
the distinct molecular size difference between 12CBP and 12CTB, the
resulting ternary supramolecular copolymers, P4VP(12CBP)
x
(12CTB)
y
, possess a homogeneous
ΦH phase at x ≥ 0.1 and y ≥ 0.2. Each column is constructed with P4VP as
the backbone tethered with mixed side chains. The column diameter
is between the size of the corresponding P4VP(12CBP)
x+y
and P4VP(12CTB)
x+y
and could be easily tuned by varying x and y. The enhancement of ΦH in
supramolecular copolymers is attributed to the entropy effect of the
mixed side chain and enthalpy effect from hydrogen bonding interaction
of the P4VP backbone and two molecules (12CBP and 12CTB).
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.