4 research outputs found
Reinforcement of a Sugar-Based Bolaamphiphile/Functionalized Graphene Oxide Composite Gel: Rheological and Electrochemical Properties
A sugar-based bolaamphiphile/graphene
oxide composite hydrogel
has been prepared using simple mixing. Unlike the corresponding sugar-based
native gel, the composite gel exhibits a fibrillar structure with
a 10–20 nm fiber diameter. The composite gel forms an interdigitated
bilayer structure incorporating intermolecular hydrogen-bonding interactions.
The composite gel formation did not change the beneficial electrical
properties of graphene offering the potential for integration of this
new material into electronic systems. Interestingly, the mechanical
and electrochemical properties of the composite gel are both dramatically
enhanced when compared to the native gel, thereby reflecting that
the functionalized graphene oxide layers are efficiently intercalated
within the composite gel structure
Bis(naphthol)-based fluorescent chemoprobe for cesium cation and its immobilisation on silica nanoparticle as a high selective adsorbent
<p>A bis(naphthol)-based cation receptor <b>1</b> has been synthesised by three steps of synthetic procedure. The spectroscopic properties of <b>1</b> upon addition of various metal ions were investigated by UV–vis absorption and fluorescence spectroscopy. As a result, the absorption of <b>1</b> was linearly decreased as a function of concentration of added Cs<sup>+</sup>. Also, <b>1</b> exhibited dramatic fluorescence quenching effect upon exposure to caesium cation. Contrastively, no significant quenching effect was observed upon addition of other metal ions such as Na<sup>+</sup>, K<sup>+</sup>, Rb<sup>+</sup>, Mg<sup>2+</sup>, Ca<sup>2+</sup>, Sr<sup>2+</sup>, Ba<sup>2+</sup>, Ni<sup>2+</sup> and Zn<sup>2+</sup>. It was found that <b>1</b> formed a 1:1 complex with Cs<sup>+</sup> by Job’s plot. Furthermore, we also prepared <b>1</b>-functionalised silica nanoparticle (<b>SiO</b><sub><b>2</b></sub><b>-1</b>) as an adsorbent for Cs<sup>+</sup>. <b>SiO</b><sub><b>2</b></sub><b>-1</b> showed a great capacity for selective removal of caesium ion from aqueous solution as well as from tap water. Thus, it is potentially useful for the detection and removal of caesium cation from environmental and biological fluids polluted by nuclear radiation and nuclear waste.</p
Chiral Supramolecular Gels with Lanthanide Ions: Correlation between Luminescence and Helical Pitch
We report the correlation
between the fluorescence intensity and the helical pitch of supramolecular
hydrogels with TbÂ(III) and EuÂ(III) as well as their inkjet printing
patterning as an application. The luminescent gels, which exhibited
three different emissions of red, green, and blue, could be prepared
without and with EuÂ(III) and TbÂ(III). The luminescence intensity of
supramolecular gels (gel-Tb and gel-Eu) composed of TbÂ(III) and EuÂ(III)
was ca. 3-fold larger than that of the sol (<b>1</b>+TbÂ(III)
or <b>1</b>+EuÂ(III)), which was attributed to large tilting
angles between molecules. By AFM observations, these gels showed well-defined
right-handed helical nanofibers formed by coordination bonds in which
the helical pitch lengths were strongly dependent on the concentrations
of lanthanide ions. In particular, the large luminescence intensity
of gel-Tb exhibited a smaller helical pitch length than that of gel-<b>1</b> due to relatively weak π–π stacking with
large tilting angles between molecules. The luminescence intensities
were enhanced linearly with increasing concentrations of lanthanide
ions. This is the first example of the correlation between the helical
pitch length and the luminescence intensity of supramolecular materials.
The coordination bonding in supramolecular hydrogels had a strong
influence on rheological properties. We also developed a water-compatible
inkjet printing system to generate luminescent supramolecular gels
on A4-sized paper. The images of a logo and the text were composed
of three different emissions and were well-printed on A4 sized paper
coated with gel-<b>1</b>
Transfer and Dynamic Inversion of Coassembled Supramolecular Chirality through 2D-Sheet to Rolled-Up Tubular Structure
Transfer and inversion of supramolecular
chirality from chiral calix[4]Âarene analogs (<b>3D</b> and <b>3L</b>) with an alanine moiety to an achiral bipyridine derivative
(<b>1</b>) with glycine moieties in a coassembled hydrogel are
demonstrated. Molecular chirality of <b>3D</b> and <b>3L</b> could transfer supramolecular chirality to an achiral bipyridine
derivative <b>1</b>. Moreover, addition of 0.6 equiv of <b>3D</b> or <b>3L</b> to <b>1</b> induced supramolecular
chirality inversion of <b>1</b>. More interestingly, the 2D-sheet
structure of the coassembled hydrogels formed with 0.2 equiv of <b>3D</b> or <b>3L</b> changed to a rolled-up tubular structure
in the presence of 0.6 equiv of <b>3D</b> or <b>3L</b>. The chirality inversion and morphology change are mainly mediated
by intermolecular hydrogen-bonding interactions between the achiral
and chiral molecules, which might be induced by reorientations of
the assembled molecules, confirmed by density functional theory calculations