Two kinds of fluoroalkyl end-capped vinyltrimethoxysilane oligomer [RF-(VM)n-RF] silica nanocomposites containing biphenylene units were prepared by the sol-gel reactions of the corresponding oligomer
with biphenylene-bridged ethoxysilanes or 4,4′-biphenol under alkaline conditions, respectively. One is the fluorinated oligomer/silica
nanocomposites containing biphenylene units [RF-(VM-SiO2)n–RF/Ar-SiO2], of whose biphenylene units were incorporated into nanocomposite cores through the siloxane bondings, and the other is the
fluorinated oligomer/silica nanocomposites containing biphenylene units [RF-(VM-SiO2)n–RF/Biphenol], of whose biphenylene units were directly encapsulated into nanocomposite cores through the sol–gel process. Interestingly,
the shape of RF-(VM-SiO2)n–RF/Ar-SiO2 nanocomposites is morphologically controlled cubic particles; although the shape of RF-(VM-SiO2)n–RF/Biphenol nanocomposites is spherically fine particles. Thermogravimetric analyses 2H magic-angle spinning nuclear magnetic resonance, Ultraviolet visible, and fluorescent spectra showed that biphenylene units
in RF-(VM-SiO2)n–RF/Ar-SiO2 nanocomposites have a flammable characteristic after calcinations at 800 °C; in contrast, biphenylene units in RF-(VM-SiO2)n–RF/Biphenol nanocomposites have a nonflammable characteristic even after calcination at 800 °C. X-ray photoelectron spectroscopy analyses
of these two kinds of fluorinated nanocomposites showed that nonflammable characteristic toward biphenylene units in the silica
gel matrices is due to the formation of ammonium hexafluorosilicate during the sol–gel process. 相似文献
Cross-linked fluoroalkyl end-capped cooligomers possessing double decker-type aromatic silsesquioxane segments as core units
[RF-(Ar-SiSQ)x-(Co-M)y-RF] were prepared under mild conditions by the cooligomerizations of fluoroalkanoyl peroxide with the corresponding aromatic
silsesquioxane possessing bifunctional vinyl groups (Ar-SiSQ) and comonomers (Co-M) such as acryloylmorpholine (ACMO), N,N-dimethylacrylamide (DMAA) and N-(1,1-dimethyl-3-oxobutyl)acrylamide (DOBAA). Interestingly, these cross-linked fluorinated cooligomers thus obtained were
found to form the nanometer size-controlled nanoparticles with a good dispersibility in a variety of solvents including fluorinated
aliphatic solvents. These fluorinated cooligomeric nanoparticles were demonstrated to have red-shifted fluorescent emissions
related to the presence of aromatic silsesquioxane segments, compared with that of parent aromatic silsesquioxane, indicating
that each aromatic moiety in these nanoparticles can interact effectively with each other through the π–π stacking between
the aromatic moieties to afford the red-shifted fluorescent emissions. These fluorinated nanoparticles were also applied to
the surface modification of poly(methyl methacrylate) (PMMA) to exhibit not only a good oleophobicity imparted by fluorine
but also a fluorescent emission behavior related to aromatic silsesquioxane segments in nanoparticles on the modified PMMA
surface. More interestingly, cross-linked RF-(Ar-SiSQ)x-(DOBAA)y-RF cooligomeric nanoparticles interacted with fluorescein to give the corresponding fluorinated cooligomeric particles/fluorescein
nanocomposites in methanol. These fluorinated fluorescein nanocomposites were found to afford an extraordinarily enhanced
light absorption (λmax = 441 nm), compared with that of fluoroalkyl end-capped DOBAA oligomer [RF-(DOBAA)n-RF] possessing no aromatic silsesquioxane segments. 相似文献
Fluoroalkyl end-capped acrylic acid oligomer [RF-(ACA)n-RF]/, 2-(methacryloyloxy)ethanesulfonic acid oligomer [RF-(MES)n-RF]/, 2-acrylamido-2-methylpropanesulfonic acid oligomer [RF-(AMPS)n-RF]/polyaniline [PAn] nanocomposites were prepared by the polymerization of aniline initiated by ammonium persulfate in the presence of the corresponding oligomers, respectively. These fluorinated oligomers were also applied to the preparation of the corresponding fluorinated oligomers/phenyl-capped aniline dimer (An-dimer: N,N′-diphenyl-1,4-phenylenediamine) nanocomposites by the interaction of the fluorinated oligomers with An-dimer. These fluorinated composites thus obtained were found to afford nanometer size-controlled fine particles possessing a good dispersibility and stability in water and traditional organic media such as methanol. UV–vis spectra of RF-(MES)n-RF/PAn nanocomposites and RF-(AMPS)n-RF/PAn nanocomposites showed the similar absorption peaks around 350, 430, and 780 nm to those of the usual Brønsted acid-doped PAn; however, interestingly, RF-(ACA)n-RF/PAn nanocomposites were found to exhibit only an absorption peak around 430 nm based on the polaron transition.
A variety of fluoroalkyl end-capped oligomers, such as fluoroalkyl end-capped acrylic acid oligomer [RF-(ACA)n-RF], acryloylmorpholine oligomer [RF-(ACMO)n-RF], 2-acrylamido-2-methylpropanesulfonic acid oligomer [RF-(AMPS)n-RF], 2-(methacryloyloxy)ethanesulfonic acid oligomer [RF-(MES)n-RF], and N,N-dimethylacrylamide oligomer [RF-(DMAA)n-RF], were applied to the autoreduction of gold ions to give the corresponding oligomers/gold nanocomposites, of whose sharp plasmon absorption bands are observed around 535 nm. In these fluorinated oligomers, RF-(ACA)n-RF oligomer and RF-(ACMO)n-RF were effective for the one-pot preparation of the gold nanoparticles under very mild conditions; although the other fluorinated oligomers and the corresponding non-fluorinated–(ACMO)n-oligomer were unable to afford the gold nanoparticles. RF-(ACA)n-RF/SiO2 nanocomposites and RF-(ACMO)n-RF/SiO2 nanocomposites, which were prepared by the sol–gel reactions of tetraethoxysilane in the presence of silica nanoparticles and the corresponding oligomers under alkaline conditions, were also applied to the encapsulation of gold nanoparticles into these fluorinated nanocomposite cores through the autoreduction of gold ions at room temperature. Interestingly, these fluorinated oligomers/silica nanocomposite-encapsulated gold nanocomposites before and after calcination at 800 °C were found to exhibit the same plasmon absorption band around 525 nm. RF-(MES)n-RF oligomer and RF-(AMPS)n-RF oligomer are not suitable for the autoreduction of gold ions; however, RF-(MES)n-RF[or RF-(AMPS)n-RF]/polyaniline [PAn] nanocomposites, which were prepared by the polymerization of aniline initiated by ammonium persulfate in the presence of the corresponding oligomer, enabled the formation of gold nanoparticles through the oxidation of PAn in the composites at room temperature. The reversible conformational change of PAn in the nanocomposites from the polyemeraldine salt to the oxidized pernigraniline base was observed during such oxidation process. Graphical abstract
Perfluoro-2-methyl-3-oxahexanoic acid/silica nanocomposites [RF-CO2H/SiO2] were prepared by the sol–gel reaction of tetraethoxysilane in the presence of silica nanoparticles and the corresponding fluorinated carboxylic acid under alkaline conditions. RF-CO2H/SiO2 nanocomposites were found to exhibit no weight loss in proportion to the contents of fluorinated carboxylic acid in the composites even after calcination at 800 °C. The modified glass surface treated with the RF-CO2H/SiO2 nanocomposites was shown to give a good oleophobicity with superhydrophilicity imparted by fluorinated carboxylic acid in the composites. RF-CO2H/SiO2 nanocomposites were also applied to the encapsulation of a variety of low molecular weight aromatic and aliphatic compounds such as bisphenol AF [BPAF], bisphenol A [BPA], 4,4′-biphenol [BPOH], octafluoro-4,4′-biphenol [FBPOH], 4,4′-bis(triethoxysilyl)-1,1′-biphenyl [BTSBP], 3-(trihydroxysilyl)propane-1-sulfonic acid [THSP], α-cyclodextrin (α-CD), β-cyclodextrin (β-CD), and γ-cyclodextrin (γ-CD). Encapsulated aromatic compounds possessing acidic hydroxyl groups such as BPAF, BPA, and FBPOH in the RF-COOH/SiO2 nanocomposites were found to exhibit no weight loss corresponding to the contents of aromatic compounds in the composites even after calcination at 800 °C. On the other hand, encapsulated aromatic compounds possessing no acidic hydroxyl groups such as BTSBP and aliphatic compounds (THSP, α-, β-, and γ-CD) gave a clear weight loss corresponding to the contents of these compounds in the composites after calcination. In addition, the fluorinated silica nanocomposite-encapsulated these compounds were applied to the surface modification of glass to exhibit a good oleophobicity with superhydrophilicity imparted by fluorinated carboxylic acid on the surface.
Fluoroalkyl end-capped vinyltrimethoxysilane oligomer/anatase titanium oxide nanocomposite-encapsulated low molecular weight aromatic compounds [RF-(VM-SiO2)n-RF/an-TiO2/Ar-H] were prepared by the sol–gel reactions of the corresponding oligomer in the presence of anatase titanium oxide nanoparticles (an-TiO2) and the aromatic compounds such as bisphenol A [BPA], 1,1′-bi(2-naphthol) [BINOL], and fullerene under alkaline conditions. Thermogravimetric analyses measurements show that RF-(VM-SiO2)n-RF/an-TiO2 nanocomposite-encapsulated BPA and BINOL, in which the theoretical contents in the composites are 25?～?32 %, were found to give no weight loss corresponding to the contents of these aromatic compounds even after calcination at 800 °C. On the other hand, the corresponding nanocomposite-encapsulated fullerene exhibited weight loss behavior related to the presence of fullerene under similar conditions; however, UV–vis spectra showed the presence of the residual fullerene in the composites even after calcination. An-TiO2 in these fluorinated nanocomposites can keep its crystalline structure without phase transformation into rutile even after calcination at 1,000 °C, although the parent an-TiO2 nanoparticles underwent a complete phase transformation into rutile under similar conditions. Notably, RF-(VM-SiO2)n-RF/an-TiO2/Ar-H nanocomposites can give a good photocatalytic activity even after calcination at 1,000 °C for the decolorization of methylene blue under UV light irradiation. More interestingly, these fluorinated nanocomposites before and after calcination were found to exhibit a higher photocatalytic activity at the initial UV light irradiation from 1 to 3 min than that of the corresponding RF-(VM-SiO2)n-RF/an-TiO2 nanocomposites under similar conditions.
Figure
Encapsulated BPA and BINOL in the nanocomposites exhibit no weight loss even after calcination at 800 °C, and RF-(VM-SiO2)n-RF/an-TiO2/Ar-H nanocomposites before and after calcination at 1,000 °C can give a higher photocatalytic activity than that of RF-(VM-SiO2)n-RF/an-TiO2 nanocomposites. Notably, the photocatalytic activity of RF-(VM-SiO2)n-RF/an-TiO2/C60 nanocomposites after calcination increased by about 2.5-fold, compared with that of RF-(VM-SiO2)n-RF/an-TiO2 nanocomposites. 相似文献
A unique cluster-based cationic framework was successfully constructed by a mixed-ligand strategy. Due to the cationic network and guest anionic molecules in 1D open channels, the MOF can rapidly and selectively adsorb anionic dyes in ethanol solution and release dyes easily based on chargeexclusive effect. 相似文献
Thiophene monomer reacted with ferric chloride in the presence of a variety of fluoroalkyl end-capped N-(1,1-dimethyl-3-oxobutyl)acrylamide oligomers [RF-(DOBAA)x-RF] to afford nanometer size-controlled RF-(DOBAA)x-RF oligomers-polythiophene composites [RF-(DOBAA)x-RF/PTh]. RF-(DOBAA)x-RF/PTh nanocomposites thus obtained were demonstrated to have a good dispersibility and stability in methanol to give a transparent brown solution. In addition, these fluorinated nanocomposites were applied to the surface modification of common organic polymers such as poly(methyl methacrylate), and were dispersed regularly above the polymer surface. 相似文献
We have studied on the solubilization of single-walled carbon nanotubes (SW-CNTs) into aqueous and organic media by the use of a variety of nanometer size-controlled fluorinated self-assemblies, which were formed by the aggregations of end-capped fluoroalkyl segments in fluoroalkyl end-capped acrylic acid oligomers [RF-(ACA)n-RF], N,N-dimethylacrylamide oligomers [RF-(DMAA)n-RF], acryloylmorpholine oligomers [RF-(ACMO)n-RF], and N-(1,1-dimethyl-3-oxobutyl)acrylamide oligomers [RF-(DOBAA)n-RF]. Fluorinated self assemblies formed in organic media (colorless solutions) could solubilize SW-CNTs into organic media to afford the transparent pale yellow solutions. The dynamic light scattering measurements showed that the size of fluorinated self-assemblies increased after the solubilization of SW-CNTs into organic media. It was suggested that the solubilization of SW-CNTs into organic media is due to the encapsulation of SW-CNTs into fluorinated assemblies. Fluorinated assemblies were also able to solubilize SW-CNTs into water to give the transparent gray solutions. Among a variety of fluorinated assemblies, fluorinated assemblies formed by RF-(ACMO)n-RF [RF = CF(CF3)OC6F13] oligomer was more effective for the solubilization of SW-CNTs into both aqueous and organic media. Contact angle measurements of dodecane and the fluorescence spectra for poly(methyl methacrylate) cast film modified by fluorinated self-assemblies—SW-CNTs complexes showed that SW-CNTs are dispersed above the PMMA surface. 相似文献
Zinc oxide-ternary heterostructure Mn3O4/ZnO/Eu2O3 nanocomposites were successfully prepared via waste curd as fuel by a facile one-pot combustion procedure. The fabricated heterostructures were characterized utilizing XRD, UV–Visible, FT-IR, FE-SEM, HRTEM and EDX analysis. The photocatalytic degradation efficacy of the synthesized ternary nanocomposite was evaluated utilizing model organic pollutants of methylene blue (MB) and methyl orange (MO) in water as examples of cationic dyes and anionic dyes, respectively, under natural solar irradiation. The effect of various experimental factors, viz. the effect of a light source, catalyst dosage, irradiation time, pH of dye solution and dye concentration on the photodegradation activity, was systematically studied. The ternary Mn3O4/ZnO/Eu2O3 photocatalyst exhibited excellent MB and MO degradation activity of 98% and 96%, respectively, at 150 min under natural sunlight irradiation. Experiments further conclude that the fabricated nanocomposite exhibits pH-dependent photocatalytic efficacy, and for best results, concentrations of dye and catalysts have to be maintained in a specific range. The prepared photocatalysts are exemplary and could be employed for wastewater handling and several ecological applications. 相似文献
Fluoroalkyl end-capped cooligomers having adamantane as a pendant group [RF-(Ad-HAc)x–(Co-M)y-RF] were prepared by the reactions of fluoroalkanoyl peroxide with 3-hydroxy-1-adamantylacrylate (Ad-HAc) and comonomers (Co-M)
such as acrylic acid (ACA), N,N-dimethylacrylamide (DMAA), and acryloylmorpholine (ACMO) under mild conditions. Thermogravimetric analyses (TGA) showed that
thermal stability of RF-(Ad-HAc)x–(Co-M)y-RF was superior to that of the corresponding fluoroalkyl end-capped cooligomers having adamantane in the main chains [RF-(Ad)x–(Co-M)y-RF] and the fluoroalkyl end-capped homooligomers possessing no adamantyl segments [RF-(M)n-RF]. It is interesting to note that fluoroalkyl end-capped Ad-Hac–DMAA cooligomer [RF-(Ad-HAc)x–(DMAA)y-RF] was found to form the nanometer size-controlled cooligomeric aggregates which consist of around 16 fluorinated cooligomeric
molecules in methanol/water mixed solvents. Furthermore, these fluorinated cooligomeric aggregate could occupy around 320
ADMDD [5-(2-adamantylidene)-2,2-dimethyl-1,3-dioxane-4,6-dione] molecules as guest molecules per aggregate core, although
ADMDD could not be encapsulated into the RF-(Ad)x–(Co-M)y-RF cooligomeric and RF-(M)n-RF homooligomeric aggregate cores under similar conditions. 相似文献
Hyperbranched polyethylenimine (HPEI) was simply mixed with a solution of amphiphilic calix[4]arene (AC4), which possesses four phenol groups and four aliphatic chains, in chloroform. This resulted in the novel supramolecular complex HPEI–AC4 through the noncovalent interaction of the amino groups of HPEI with the phenol groups of AC4. The formed HPEI–AC4 supramolecular complexes were characterized by 1H NMR spectroscopy and dynamic light scattering. The cationic water‐soluble dye methyl blue (MB) and the anionic water‐soluble dye methyl orange (MO) were used as the model guests to test the performance of HPEI–AC4 as a supramolecular nanocarrier. It was found that HPEI–AC4 could accommodate the anionic water‐soluble MO guests into the HPEI core. The MO encapsulation capacity of HPEI–AC4 was pH sensitive, which reached maximum loading under weakly acidic conditions. The loaded MO molecules could be totally released when the pH value was reduced to be around 4.5 or raised to be around 9.5, and this process was reversible. HPEI–AC4 could not only accommodate the anionic MO with the HPEI core but could also simultaneously load the cationic MB molecules using the formed AC4 shell, thereby realizing the site isolation of the two kinds of functional units. The amount of MO and MB encapsulated by HPEI–AC4 could be controlled by varying the ratio of hydroxyl groups of AC4 to amino groups of HPEI. 相似文献
Metal–organic frameworks (MOFs) are widely used as porous materials in the fields of adsorption and separation. However, their practical application is largely hindered by limitations to their processability. Herein, new UiO‐66‐Urea‐based flexible membranes with MOF loadings of 50 ( 1 ), 60 ( 2 ), and 70 wt % ( 3 ) were designed and prepared by post‐synthetic polymerization of UiO‐66‐NH2 nanoparticles and a polyurethane oligomer under mild conditions. The adsorption behavior of membrane 3 towards four hydrophilic dyes, namely, eosin Y (EY), rhodamine B (RB), malachite green (MG), and methylene blue (MB), in aqueous solution was studied in detail. It exhibits strong adsorption of EY and RB but weak adsorption of MG and MB in aqueous solution. Owing to the selective adsorption of these hydrophilic dyes, membrane 3 can remove EY and RB from aqueous solution and completely separate EY/MB, RB/MG, and RB/MB mixtures in aqueous solution. In addition, the membrane is uniformly textured, easily handled, and can be reused for dye adsorption and separation. 相似文献
Fluoroalkyl end-capped N-(1,1-dimethyl-3-oxobutyl)acrylamide oligomer [RF-(DOBAA)n-RF] reacted with hibitane in methanol at 90 °C to afford RF-(DOBAA)n-RF oligomeric nanoparticles-encapsulated hibitane in good isolated yields. These fluorinated oligomeric particles-encapsulated hibitane were nanometer size-controlled very fine particles, and were found to exhibit a good dispersibility and stability in a wide variety of traditional organic solvents including fluorinated aliphatic solvents. Each dispersed solution with fluorinated nanoparticles afforded transparent colorless solution. These fluorinated nanoparticles were also found to exhibit a good antibacterial activity, and were applied to the surface modification of traditional organic polymers such as poly(methyl methacrylate). 相似文献
Advanced oxidation processes (AOPs) counting heterogeneous photocatalysis has confirmed as one of the preeminent method for waste water remediation. In the present work, we have successfully fabricated novel visible-light-driven nitrogen-doped graphene (NG) supported magnetic ZnO/ZnFe2O4 (ZnO/ZF/NG) and ZnO/CoFe2O4 (ZnO/CF/NG) nanocomposites. ZnO synthesized via direct precipitation method. Hydrothermal method was used for the preparation of nitrogen-doped graphene supported magnetic ZnO/ZF (ZnO/ZnFe2O4) and ZnO/CF (ZnO/CoFe2O4) nanocomposites. The procured materials were scrutinized by assorted characterizations to acquire information on their chemical composition, crystalline structure and photosensitive properties. The absorption and photocatalytic performance of photocatalysts were studied via UV–Visible spectra. Photodegradation performance of the synthesized nanocomposites was estimated toward mineralization of methyl orange (MO) and malachite green (MG) dyes in aqueous solution. The high surface area of ZnO/ZF/NG and ZnO/CF/NG was suitable for adsorptive removal of MO and MG dyes. The photodegradation performance of heterojunction photocatalysts was superior to bare photocatalyst in 140 min under visible-light irradiation. Spectrophotometer, GC–MS (Gas chromatography–mass spectrometry) elucidation was carried out to expose the possible intermediates formed. Both ZnO/ZF/NG and ZnO/CF/NG were rapidly isolated from the aqueous phase by applying an external magnetic field in 20 sec and 2 min, respectively. The photocatalytic performance and stability of ZnO/ZF/NG and ZnO/CF/NG nanocomposites were confirmed by conducting 10 consecutive regeneration cycles. Owing to recyclability of ZnO/ZF/NG and ZnO/CF/NG, these heterogeneous nanocomposites might be used as cost-effective for treatment of discarded water. The observations endorse that the synthesized ternary heterogeneous nanocomposites facilitates wastewater decontamination using photocatalytic technology. 相似文献
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