Fluorescent Hydrogels with Tunable Nanostructure and Viscoelasticity for Formaldehyde Removal

Abstract

Hydrogels with ultrahigh water content, ∼99 wt %, and highly excellent mechanical strength were prepared by 4'-para-phenylcarboxyl-2,2':6',2″-terpyridine (PPCT) in KOH aqueous solution. The self-assembled structure, rheological properties, and the gel-sol transformation temperature (Tgel-sol) of PPCT/KOH hydrogels that depend on PPCT and KOH concentrations were studied, indicating easily controllable conditions for producing hydrogels in PPCT and KOH mixtures. An important finding was that the hydration radius (Rh) of cations (M(+) = Li(+), Na(+), K(+), Cs(+), NH4(+), (CH3)4N(+), (CH3CH2)4N(+), (CH3CH2CH2)4N(+), (CH3CH2CH2CH2)4N(+)) plays a vital role in gelation of PPCT/MOH systems. To produce hydrogels in PPCT/MOH systems, the Rh of M(+) must be in a suitable region of 3.29 to 3.58 Å, e.g., K(+), Na(+), Cs(+), and the capability of M(+) for inducing PPCT to form hydrogels is K(+) > Na(+) > Li(+), which is followed by the Hofmeister series. The hydrogels of PPCT and KOH mixtures are responsive to external stimuli including temperature and shearing force, and present gelation-induced enhanced fluorescence emission property. The states of being sensitive to the stimuli can readily recover to the original hydrogels, which are envisaged to be an attracting candidate to produce self-healing materials. A typical function of the hydrogels of PPCT and KOH mixtures is that formaldehyde (HCHO) can speedily be adsorbed via electrostatic interaction and converted into nontoxic salts (HCOOK and CH3OK), making it a promising candidate material for HCHO removal in home furnishings to reduce indoor environmental pollutants.

Investigation on the self-assembled behaviors of C18unsaturated fatty acids in arginine aqueous solution

“…The structures of these aggregates, including micelles, 1,2 vesicles, 3,4 bilayers, 5,6 bers 7,8 etc., can inuence the properties of surfactant solutions such as their solubilization ability for hydrophobic substances 9 or their viscous and viscoelastic properties, 10 and their performance in various applications. These self-assembled structures possess numerous applications in many elds, such as nanotechnology, 10,11 environment 12,13 and biomedicine.…”

Metal‐organic gels of simple chemicals and their high efficacy in removing arsenic(V) in water

“…The t* reflecting the strength of the gels is the yield stress. It refers to the critical shear stress when the gel structure is destroyed under an increasing stress . Figure b presents that at fixed ligands and Fe 3+ ratio (1:1), the yield stress increases gradually ranging from 79 to 9037 Pa and then to 3162 Pa with the increase of the concentration.…”

A rechargeable self-healing safety fuel gel

“…The selectivity of compound 1 for forming a gel only in methanol or ethanol makes it an interesting candidate in separation of various miscible organic solvents. 64 If we have a mixture of ethyl acetate and methanol, we can separate the methanol by forming a gel. By the addition of a little amount of compound 1 and aqueous KOH to this ethyl acetate-methanol mixture, the compound will form a gel only with methanol and precipitate out.…”