[39] designed a supramolecular polymer with light/heat double stimulus response
SP7. Short-time heating (1 min) of the supramolecular polymer solution will only
lead to decomposition of the host and guest complexes. However, prolonged heating
(1 day) and recooling will result in the depolymerization of anthracene dimer units.
The depolymerization of the unit, which forms an oligomer, can be restored to its
original supramolecular state by cooling or light irradiation, but it is to be noted that
the transition time of the polymer to the monomer is too long to achieve effective
light control.
Huang et al. (2018) [40] constructed a novel fluorescent supramolecular crosslinked polymer network with aggregation-induced enhanced emission (AIEE)
properties via pillar[5]arene-based host–guest recognition, seen in Fig. 16. The
crosslinking and decrosslinking processes of the supramolecular polymer network
could be controlled by external stimuli including temperature and addition of
competitive guests, consequently leading to changes in fluorescence intensity.
Moreover, the fluorescent supramolecular polymer network could be further used
for the detection of nitrocompound explosives, exhibiting its practical application
in our daily life. This work is the combination of supramolecular chemistry and
conjugated polymer science and the co-built supramolecular network system
may pave a new way to develop novel multifunctional fluorescent materials in the
future.
Yao et al. (2015) [41] constructed a kind of fluorescent supramolecular polymer
driven by pillararene-based molecular recognition and metal coordination, shown in
Fig. 17. The phase transitions of the fluorescent supramolecular polymer could be
realized by subsequent alteration of heating and cooling, and the fluorescent supramolecular polymer showed base-stimulus responsive property. This supramolecular
polymer has concentration controllable fluorescence emissions. Moreover, a thin
film of the fluorescent supramolecular polymer was prepared, which was confirmed
to be a convenient test kit for detecting OH anions. This work may be of high
importance for developing novel functional fluorescent materials and molecular
devices in the future.
16.6.2 Supramolecular Polymer with Photoisomerism Based on
Pillararene
The construction of supramolecular systems with azobenzene as bridging agent
has recently set off a boom. Yu et al. (2014) [42] represented a linear supramolecular
polymer and a supramolecular polymer network, and both of them were based
on the host–guest interactions with photoresponsive characteristics. The linear
supramolecular polymer was fabricated from self-assembly of an azobenzene moiety
acting as a molecular bridge, pillar[5]arene dimer and a bisammonium salt. The
supramolecular polymer network was constructed by the secondary ammonium
salt which exhibited the recognition of molecular motif. The presence of the
host–guest complexation made it possible of the reversible transitions between
polymer–oligomer and polymer–monomer upon UV irradiation and PH changes.
16 Photoresponsive Supramolecular Polymers Based on Host-Guest Interactions
471
SP7. Short-time heating (1 min) of the supramolecular polymer solution will only
lead to decomposition of the host and guest complexes. However, prolonged heating
(1 day) and recooling will result in the depolymerization of anthracene dimer units.
The depolymerization of the unit, which forms an oligomer, can be restored to its
original supramolecular state by cooling or light irradiation, but it is to be noted that
the transition time of the polymer to the monomer is too long to achieve effective
light control.
Huang et al. (2018) [40] constructed a novel fluorescent supramolecular crosslinked polymer network with aggregation-induced enhanced emission (AIEE)
properties via pillar[5]arene-based host–guest recognition, seen in Fig. 16. The
crosslinking and decrosslinking processes of the supramolecular polymer network
could be controlled by external stimuli including temperature and addition of
competitive guests, consequently leading to changes in fluorescence intensity.
Moreover, the fluorescent supramolecular polymer network could be further used
for the detection of nitrocompound explosives, exhibiting its practical application
in our daily life. This work is the combination of supramolecular chemistry and
conjugated polymer science and the co-built supramolecular network system
may pave a new way to develop novel multifunctional fluorescent materials in the
future.
Yao et al. (2015) [41] constructed a kind of fluorescent supramolecular polymer
driven by pillararene-based molecular recognition and metal coordination, shown in
Fig. 17. The phase transitions of the fluorescent supramolecular polymer could be
realized by subsequent alteration of heating and cooling, and the fluorescent supramolecular polymer showed base-stimulus responsive property. This supramolecular
polymer has concentration controllable fluorescence emissions. Moreover, a thin
film of the fluorescent supramolecular polymer was prepared, which was confirmed
to be a convenient test kit for detecting OH anions. This work may be of high
importance for developing novel functional fluorescent materials and molecular
devices in the future.
16.6.2 Supramolecular Polymer with Photoisomerism Based on
Pillararene
The construction of supramolecular systems with azobenzene as bridging agent
has recently set off a boom. Yu et al. (2014) [42] represented a linear supramolecular
polymer and a supramolecular polymer network, and both of them were based
on the host–guest interactions with photoresponsive characteristics. The linear
supramolecular polymer was fabricated from self-assembly of an azobenzene moiety
acting as a molecular bridge, pillar[5]arene dimer and a bisammonium salt. The
supramolecular polymer network was constructed by the secondary ammonium
salt which exhibited the recognition of molecular motif. The presence of the
host–guest complexation made it possible of the reversible transitions between
polymer–oligomer and polymer–monomer upon UV irradiation and PH changes.
16 Photoresponsive Supramolecular Polymers Based on Host-Guest Interactions
471