Multistimuli-responsive organogels based on hydrazide and azobenzene derivatives

Gu, Xiaojun; Bai, Binglian; Wang, Haitao; Li, Min

doi:10.1039/c6ra24886a

Cited by 22 publications

(8 citation statements)

References 26 publications

(13 reference statements)

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“…For example, a photoresponsive organogel using hydrazide and azobenzene derivatives was reported by Li and co-workers. 22 These organogels were shown to undergo a gelto-precipitate transition upon exposure to UV light. Recently, a light-responsive organogel based on arylazopyrazole gelators that undergoes reversible sol−gel transitions and stiffness changes has been reported.…”

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confidence: 99%

Reversibly Softening and Stiffening Organogels Using a Wavelength-Controlled Disulfide-Diselenide Exchange

et al. 2020

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Wavelength-dependent light-responsive seleno-sulfide dynamic covalent bonds were used to prepare organogels with reversible changes in stiffness. The disulfide cross-link organogels prepared from norbornene-terminated poly(ethylene glycol) (PEG-diNB) and poly(2-hydroxypropyl methacrylate-stat-mercaptoethyl acrylate) (PEG-diNB-poly(HPMA-stat-MEMA)) polymers underwent exchange reactions with 5,5′-diselenide-bis(2-aminobenzoic acid) upon irradiation with UV light. Following irradiation with visible light, the seleno-sulfide bonds were cleaved, reforming disulfide cross-links and the 5,5′-diselenide-bis(2-aminobenzoic acid). Reduction in G′ with disulfide–diselenide exchange was consistent with that observed following a thiol–disulfide exchange reaction. Recovery of G′ upon disulfide bond formation was 85–95% of the initial value in the as-prepared gel over five cycles of bond cleaving and reformation. This initial study shows the potential of the wavelength-controlled disulfide–diselenide chemistry to develop light-responsive reversible organogels. These organogels have the potential to be used in functional materials such as polymeric actuators or biomimetic soft robotics.

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Reversibly Softening and Stiffening Organogels Using a Wavelength-Controlled Disulfide-Diselenide Exchange

et al. 2020

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“…The peak at 1386 cm -1 was attributed to C-H bending modes in FSi1, FSi2, and FSi3 26 . Meanwhile, an additional peak of N–H was detected at 1580 cm -1 and a free C = O bond was observed at around 1701 cm -1 in the FSi1, FSi2, and FSi3 27 , 28 . Their existence indicates that the structure of the fungal fibers changed due to the absorption of Si source.…”

Section: Resultsmentioning

confidence: 99%

Development and characterization of novelly grown fire-resistant fungal fibers

Zhang

Fan

et al. 2022

Sci Rep

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This study conducted a comprehensive characterization and analyses on the fire-resistant behaviors of novel fungal fibers grown with substrate containing Silica (Si) source at multiple scales. At micro-scale, the results of SEM showed that silica affected the physiological activities of fungi, with the extent of effects depending upon its concentration. Fourier-transform infrared (FTIR) spectra displayed the existence of Si–O–C chemical bonds in fungal fibers grown with Si source, indicating that Si source becomes a part of the structure of fungal fibers. Thermogravimetric analysis (TGA) and Microscale combustion calorimetry (MCC) of fungal fibers exhibit an early thermal decomposition of non-combustible components, which will potentially help release the thermal stress and mitigation of spalling when used in concrete. Compared with polypropylene (PP) fibers, fungal fibers have a lower thermal degradation rate, a higher residual weight, a lower heat release peak temperature, and less total heat of combustion; all of these indicate improved thermal stability and fire resistance, and a lower rate of function loss in case of a fire. Additionally, the thermal stability and fire resistance of fungal fibers were improved with the increase of Si source concentration in the nutrition medium. For example, addition of 2% Si source in the feeding substrate leads to a 23.21% increase in residual weight in TGA, and a 23.66 W/g decrease in peak heat release rate as well as a 2.44 kJ/g reduction in total heat of combustion in MCC. At laboratory scale, compared with PP fibers, fungal fibers grown with 2% Si source have a higher residual weight of 40.40%, a higher ignition temperature of 200.50 °C, and a declined flame height of 11.64 mm in real fire scenarios. Furthermore, only in the fungal fibers grown with Si source, partial burning occurred. In post-fire conditions, the microstructure of residual char from fungal fibers grown with higher content of Si source became denser, which would lead to a reduction of the fuel vapor release and heat transfer. FTIR spectra of residual char demonstrated that fungal fibers grown with Si source formed more stable chemical bonds with higher heat of chemical bond formation, contributing to improved thermal stability and fire resistance. Therefore, compared with traditional fibers used for fiber reinforced concrete, incorporating the new natural grown fibers will potentially further improve the fire resistance of concrete and mitigate the concrete spalling.

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“…As the spacer length and parity of the end group affect the gelation ability, [11a,c,f] odd/even number of the alkyl group as spacer could affect the intermolecular linking between terminal phenolate moieties and may distort the molecular conformation at aggregation stage, in turn, produce obstruction for gelation [11] . A shorter length of the spacer may induce strain/repulsion while extremely large spacer length would lead to high entropy and hence lesser probability of creation of a well‐organised system i. e .…”

Section: Resultsmentioning

confidence: 99%

Bis(Acylhydrazone)‐Based Bolaamphiphiles: Effect of Spacer Length on Metalloorganogel Formation, Fluorescence, and Conductance Properties

et al. 2022

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Gelation of chain-length-selective bolaamphiphiles (1 % w/v) from succinic (n = 2, H 2 SL) and adipic acid (n = 4, H 2 AL) derived ligands from six different bis(acylhydrazone)-based saturated homologous dicarboxlylates has been demonstrated. Deprotonation of H 2 SL (SL 2À ) with LiOH led to the formation of a fluorescent metalloorganogel upon addition of Cd(OAc) 2 . The coordination complexes responsible for metalloorganogel or solution formation have been studied with UV/Vis, Job's plot, ESI-MS and fluorescence studies. Transmission electron microscopy (TEM) of the diluted metalloorganogel revealed unusual nanospherical aggregates (~50 nm diameter) aligned together to create fibrous morphology, which was further supported by scanning electron microscopy (SEM) imaging. Nyquist impedance plot indicated that the metalloorganogel has a much lower resistance (R1 = 3.6 kΩ) than its non-gelling counterpart (R2 = 5.6 kΩ) suggesting the formation of well-organized fibres.

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Multistimuli-responsive organogels based on hydrazide and azobenzene derivatives

Cited by 22 publications

References 26 publications

Reversibly Softening and Stiffening Organogels Using a Wavelength-Controlled Disulfide-Diselenide Exchange

Reversibly Softening and Stiffening Organogels Using a Wavelength-Controlled Disulfide-Diselenide Exchange

Development and characterization of novelly grown fire-resistant fungal fibers

Bis(Acylhydrazone)‐Based Bolaamphiphiles: Effect of Spacer Length on Metalloorganogel Formation, Fluorescence, and Conductance Properties

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