Co-reporter:Li Wei, Wu Yonggang, Shen Shukun, Song Shaofei, and Hu Daodao
The Journal of Physical Chemistry B 2016 Volume 120(Issue 35) pp:9513-9522
Publication Date(Web):August 9, 2016
DOI:10.1021/acs.jpcb.6b05477
The gelation of 3-methacryloxypropyltrimethoxysilane (MAPTMS) is much more difficult to achieve in conventional conditions. This article describes a novel and concise approach to acquire transparent and firm hybrid gel material by one step promptly without photoinitiator or other tetraalkoxysilane. MAPTMS was hydrolyzed in acidified aqueous solution, which became homogeneous sol in 3 min, and then the sol was irradiated with UV light for a few minutes to form gel. The experimental results indicated that MAPTMS sol gelled in the presence of UV-irradiation was mainly attributed to altering Si–O–Si skeleton structure through hydroxyl radicals, and the gelation originated from the hydrolytic polycondensation of MAPTMS rather than the polymerization of methacryloxy substituent groups. The hydroxyl radicals could break the Si–O–Si ring structure to form cross-linker like species, and these cross-linkers chemically joined linear chains together to form the gel network. This investigation offers not only the photoinduced gelation strategy for MAPTMS sol but also the new insight into the effect of UV-irradiation on the sol–gel process of organotrialkoxysilanes.
Co-reporter:Juxiang Yang, Daodao Hu, Wei Li, Xing Yang
Microporous and Mesoporous Materials 2015 Volume 202() pp:165-174
Publication Date(Web):15 January 2015
DOI:10.1016/j.micromeso.2014.08.008
•The main virtue of microreactors is high surface area and loaded amount of catalyst.•The microreactors have porous microgels core and phase transfer catalysts shell.•The core stores oxidant (H2O2), and the shell is amphiphilic and catalytic.•The microreactors make integration of reactor and extractor into one system.•The catalyst showed good catalytic performance and reusability.Two kinds of microreactors using the porous and imperforate poly(acrylamide-co-methacrylic acid) (P(AM-co-MAA)) microgels as cores and the phase transfer catalysts (the complex between 3-(trimethoxysilyl)-propyldimethyloctadecylammonium chloride (AEM) and K2{W(O)(O2)2 (H2O)}2 (W2)) as shell, were respectively prepared. The prepared microreactors were characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR) and energy-dispersive X-ray spectrophotometer (EDX). The results indicated that the P(AM-co-MAA)/AEM/W2 microreactor with porous core has the turtle shell-like surface but that with imperforate core has smooth surface. The following results regarding the oxidation of dibenzothiophene (DBT) catalyzed by the two kinds of microreactors were obtained. Although amount of phase transfer catalysts loaded in the microreactors with the turtle shell-like surface is obviously higher than that of the microreactors with smooth surface, the catalytic efficiency of the microreactors with the turtle shell-like surface is obviously lower than that of the microreactors with smooth surface. The results imply that the effect of the distribution of phase transfer catalysts in the core–shell microreactors on the catalytic efficiency is more remarkable than that of the loaded amount of catalysts.SEM images of P(AM-co-MAA) microspheres (a), P(AM-co-MAA)/AEM/W2 microreactors (b) and fourth run recovered microreactors (c). Step I: P(AM-co-MAA)/AEM/W2 microreactors were prepared by hydrolysis- condensation and ion-exchange reaction. Step II: the recovered microreactors were easily obtained by washing and drying.
Co-reporter:Jing Yang, Dao-Dao Hu, Hui Zhang
Reactive and Functional Polymers 2012 72(7) pp: 438-445
Publication Date(Web):July 2012
DOI:10.1016/j.reactfunctpolym.2012.04.006
Co-reporter:Guodong Feng, Luan Jiang, Puhong Wen, Yali Cui, Hong Li and Daodao Hu
Analyst 2011 vol. 136(Issue 22) pp:4822-4829
Publication Date(Web):03 Oct 2011
DOI:10.1039/C1AN15149E
A new ion-exchange adsorbent (IEA) derived from Fe3O4/SiO2-GPTMS-DEAE with paramagnetic properties was prepared. Fe3O4 nanoparticles were firstly prepared in water-in-oil microemulsion. The magnetic Fe3O4 particles were modified in situ by hydrolysis and condensation reactions with tetraethoxysilane (TEOS) to form the core–shell Fe3O4/SiO2. The modified particles were further treated by 3-glycidoxypropyltrimethoxysilane (GPTMS) to form Fe3O4/SiO2-GPTMS nanoparticles. Fe3O4/SiO2-GPTMS-DEAE nanoparticles (IEA) were finally obtained through the condensation reaction between the Cl of diethylaminoethyl chloride-HCl (DEAE) and the epoxy groups of GPTMS in the Fe3O4/SiO2-GPTMS. The obtained IEA has features of paramagnetic and ion exchange properties because of the Fe3O4 nanoparticles and protonated organic amine in the sample. The intermediates and final product obtained in the synthesis process were characterized. The separation result of genomic DNA from blood indicated that Fe3O4/SiO2-GPTMS-DEAE nanoparticles have outstanding advantages in operation, selectivity, and capacity.
Co-reporter:Hong Li;Xin'ai Cui;Shukun Shen
Journal of Applied Polymer Science 2011 Volume 122( Issue 1) pp:509-516
Publication Date(Web):
DOI:10.1002/app.33782
Abstract
Surfmer [3-(acryloylamino)propyl]dodecyldimethyl ammonium bromide (APDDAB) was synthesized and characterized. On the basis of the reverse emulsion polymerization technique, poly[acrylamide-co-3-(acryloylamino)propyldodecyldimethylammonium bromide] [P(AM-co-APDDAB)] copolymer microgels were obtained with the copolymerization of acrylamide and APDDAB. The P(AM-co-APDDAB)/polyoxotungstates composite microspheres were prepared with the ion-exchange reaction of the P(AM-co-APDDAB) microgels with phosphotungstic acid (H3PW12O40). The morphologies and components of the composite microspheres were characterized by scanning electron microscopy, energy-dispersive X-ray spectroscopy, thermogravimetric analysis, and Fourier transform infrared spectroscopy. The results indicate that the P(AM-co-APDDAB)/PW12O40 composite microspheres all had a core–shell structure. For the composite microspheres, the hydrogel P(AM-co-APDDAB) was dominantly located in the core, and the complexes of PW12O403− with APDDAB were mainly located in the surface; these features made the composite microspheres amphiphilic and provided for potential catalysis in a two-phase reaction. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Co-reporter:Shaofei Song, Shukun Shen, Xinai Cui, Dongdong Yao, Daodao Hu
Reactive and Functional Polymers 2011 71(4) pp: 512-519
Publication Date(Web):April 2011
DOI:10.1016/j.reactfunctpolym.2011.01.003
Co-reporter:Guodong Feng, Daodao Hu, Lei Yang, Yali Cui, Xin-ai Cui, Hong Li
Separation and Purification Technology 2010 Volume 74(Issue 2) pp:253-260
Publication Date(Web):17 August 2010
DOI:10.1016/j.seppur.2010.06.013
A new method for synthesis of an Immobilized-Metal Affinity chromatography (IMAC) adsorbent with superparamagnetism (Fe3O4/SiO2-GPTMS-Asp-Co) was reported in this paper. Fe3O4 nanoparticles were first modified by SiO2 to form the core–shell Fe3O4/SiO2 with superparamagnetism, the core–shell microspheres were then successively treated by 3-glycidoxypropyltrimethoxysilane (GPTMS), l-aspartic acid (l-Asp) and 2-bromoacetic acid to form Fe3O4/SiO2-GPTMS-Asp nanoparticles with tetradentate ligands. Finally, the IMAC adsorbent with superparamagnetism, Fe3O4/SiO2-GPTMS-Asp-Co, was finally obtained by the coordination of Co2+ with the resulting nanoparticles. The intermediates and product obtained from the process mentioned above were characterized by TEM, SEM, XRD, XPS, FT-IR, TGA, AAS, EDS, element analysis and magnetic hysteresis loop. Fe3O4/SiO2-GPTMS-Asp-Co nanoparticles used as IMAC adsorbent to separate the recombinant 6-histidine-tagged gp41 protein were investigated. The result indicates that the IMAC adsorbent we prepared has outstanding advantages in the separation of the 6-histidine-tagged proteins from the crude bacterial lysate, such as simple operation, high selectivity and capacity.A immobilized-metal affinity chromatography adsorbent with paramagnetism (Fe3O4/SiO2-GPTMS-Asp-Co) was prepared. The necessity of these kinds of adsorbent can easily be understood from the description in the introduction part of this paper.
Co-reporter:Shukun Shen, Peipei Sun, Wei Li, Atul N. Parikh and Daodao Hu
Langmuir 2010 Volume 26(Issue 11) pp:7708-7716
Publication Date(Web):May 5, 2010
DOI:10.1021/la904040c
The sol−gel processes of 3-glycidoxypropyltrimethoxysilane (GPTMS) and methacryloxypropyltrimethoxysilane (MAPTMS) have been followed by fluorescence spectroscopy with pyranine as a photophysical probe. The experimental results showed that this probe is sensitive to the structural evolution and microenvironment polarity. The specific comparison of the structural evolution in two substituted organotrialkoxysilanes, namely, MAPTMS and GPTMS, illustrates the ability of the substituents to interact with the microenvironment via electrostatic interactions. Interestingly, these interactions determine the kinds of intermediate supramolecular structures that form during the sol−gel process and hence control the structure of the ensuing sol−gel end product. In particular, the amphiphile-like character of the MAPTMS intermediates contrasts with the biamphiphilic character of their GPTMS counterparts, driving distinctly different transient and local molecular organizations, which in turn modulate the hydrolysis and condensation reactions during the sol−gel process.
Co-reporter:Hong Li, Ping Zhang, Long Zhang, Tong Zhou and Daodao Hu
Journal of Materials Chemistry A 2009 vol. 19(Issue 26) pp:4575-4586
Publication Date(Web):20 May 2009
DOI:10.1039/B823075G
The composite microspheres of poly(acrylamide) microgels (PAM) surfacely covered with [3-(acryloylamino)propyl]dodecyldimethyl ammonium-tungstophosphate complexes (APDDAB-PWA) were synthesized by using an ion-exchange reaction between APDDAB located within the porous PAM microgels and PWA in aqueous solution. The morphology and component of the composite microspheres were characterized by scanning electron microscopy, Fourier transform infrared spectroscopy and thermogravimetric analysis, respectively. The results indicated that PAM/APDDAB-PWA composite microsphere with different hierarchical surface structures could be obtained by controlling the weight ratio of APDDAB to PAM microgels, cross-linking degree of PAM microgels, the amount of PWA reacted with APDDAB in PAM/APDDAB, and solvent-washing process. Although the surface morphologies of the composite microspheres in detail were different, a general feature was of the core-shell structure and the wrinkly surface covered with APDDAB-PWA particles. The formation of the wrinkly surface is attributed to the difference in shrink between inside and outside of PAM microgel frameworks, and the formation of APDDAB-PWA small particles originates from the reaction between APDDAB aggregation and PWA. This composite microsphere with PAM hydrogel core is suitable to store water-soluble substances, and the shell composed of the surfactant/Keggin-type polyoxometalate complexes is not only amphiphilic but also catalytic. Additionally, PAM/APDDAB-PWA composite microspheres with big size and APDDAB-PWA particles with small size make the composite microspheres not only easy for separation but also beneficial for catalysis. These properties have been verified by the application of PAM/APDDAB-PWA composite microspheres to the deep desulfurization of fuel oil. This material provides an example to construct microreactors with new structure used in diphase catalytic reaction.
Co-reporter:Tong Zhou;Hong Li;Guoyu Liu;Long Zhang;Dongdong Yao
Journal of Applied Polymer Science 2009 Volume 114( Issue 6) pp:4000-4010
Publication Date(Web):
DOI:10.1002/app.31034
Abstract
The composite microspheres of poly(lacrylamide) microgels (PAM) surfacely covered with [2-(methacryloyloxy)ethyl]dodecyldimethylammonium (MEDDAB)-tungstophosphate (HPW) complexes (MEDDAB-HPW) were synthesized by using ion-exchange reaction between MEDDAB located within the porous PAM microgels and HPW in aqueous solution. The morphology and component of the composite microspheres were characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, and thermogravimetric analysis, respectively. The results indicated that PAM/MEDDAB-HPW composite microsphere with different hierarchical surface structures could be obtained by controlling the weight ratio of MEDDAB to HPW in the microgels and cross-linking degree of PAM microgels. Although the surface morphologies of the composite microspheres prepared in different conditions were different, a general feature was that the composite microspheres have the core-shell structure and the wrinkly surface covered with the particles of MEDDAB-HPW complexes. The formation of the wrinkly surface is attributed to the difference in shrinkage between inside and outside of PAM microgel frameworks due to deposition of MEDDAB-HPW on the surface, and the formation of MEDDAB-HPW small particles originates from the reaction between MEDDAB aggregation and HPW. For this composite microsphere, PAM hydrogel core is suitable to store water-soluble substances, and the shell composed of the surfactant/Keggin-type polyoxometalate complexes is not only amphiphilic but also catalytic. Additionally, PAM/MEDDAB-HPW composite microspheres with big size and MEDDAB-HPW particles with small size make the composite microspheres not only easy for separation but also beneficial for catalysis. This material provides an example to construct microreactors with new structure used in diphase catalytic reaction. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Co-reporter:Shukun Shen, Daodao Hu, Peipei Sun, Xiaoru Zhang and Atul N. Parikh
The Journal of Physical Chemistry B 2009 Volume 113(Issue 41) pp:13491-13498
Publication Date(Web):September 23, 2009
DOI:10.1021/jp905069j
We report acceleration in the rate of bulk phase gelation of an organoalkoxysilane, 3-methacryloxypropyltrimethoxysilane (MAPTMS), in the presence of an amphiphilic additive, N-phenyl glycine (NPG). The MAPTMS gelation occurs within 30 min in the presence of 0.5 wt % NPG, which took several months in the absence of NPG. Using a combination of ATR-FT IR, 29Si NMR, 1H NMR, viscosity analysis, SEM, UV−vis, and π−A isotherm measurements, we elucidate the molecular-level details of the structural changes during NPG-catalyzed MPTMS gelation rate. On the basis of these results, we propose a gelation mechanism in which a transient cooperative self-assembly process fosters hydrolysis and retards early condensation thereby promoting the formation of extended three-dimensionally cross-linked gels. Specifically, the amphiphilic character of the hydrolysis product of MAPTMS, consisting of a hydrophobic tail R = −CH2CH2CH2O(CO)C(CH3)═CH2 and a hydrophilic Si−OH headgroup, promotes micelle formation at high MAPTMS/water ratio. NPG readily inserts within these micelles thus retarding the topotactic condensation of silanols at the micellar surface. This in turn allows for a more complete hydrolysis of Si−OCH3 groups prior to condensation in MAPTMS. With increased silanol concentration at the micellar periphery, a delayed condensation phase initiates. This formation of a covalently bonded Si−O−Si framework (and possibly also the formation of the methanol byproduct) likely destabilizes the micellar motif thus promoting its transformation into condensed mesophases (e.g., lamellar microstructure) upon gelation. Because of the generality of this transient and co-operative organic−inorganic self-assembly between hydrolyzed amphiphilic organoalkoxysilanes and surfactant-like amino acid additives, we envisage applications in controlling bulk phase gelation of many chain-substituted organoalkoxysilanes.
Co-reporter:Daodao Hu;Yu Fang;Gailing Gao;Mingzhen Wang
Journal of Applied Polymer Science 2006 Volume 101(Issue 4) pp:2431-2436
Publication Date(Web):27 MAY 2006
DOI:10.1002/app.24019
A chitosan (CS) derivative, N-(4-methylimidazole)-chitosan (MIC), was synthesized, and a cobalt (II) complex of bis(salicylideneethylene diamine), (CoSalen), was immobilized on it. The structure of the polymer-immobilized CoSalen was characterized by elemental analysis, IR, XPS, fluorescence and ESR spectroscopy. It was demonstrated that the immobilization of CoSalen was realized through the coordination of a nitrogen atom of the pendant group, imidazole in MIC, to the Co(II) in CoSalen. The immobilized polymer complex is more efficient than the corresponding monomeric complex in catalyzing the oxidation of DOPA using oxygen. The results may be attributed to a site isolation effect offered by the supporting polymer chain. A mechanism similar to that for enzymatic catalysis was proposed. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 2431–2436, 2006
Co-reporter:Hong Li, Ping Zhang, Long Zhang, Tong Zhou and Daodao Hu
Journal of Materials Chemistry A 2009 - vol. 19(Issue 26) pp:NaN4586-4586
Publication Date(Web):2009/05/20
DOI:10.1039/B823075G
The composite microspheres of poly(acrylamide) microgels (PAM) surfacely covered with [3-(acryloylamino)propyl]dodecyldimethyl ammonium-tungstophosphate complexes (APDDAB-PWA) were synthesized by using an ion-exchange reaction between APDDAB located within the porous PAM microgels and PWA in aqueous solution. The morphology and component of the composite microspheres were characterized by scanning electron microscopy, Fourier transform infrared spectroscopy and thermogravimetric analysis, respectively. The results indicated that PAM/APDDAB-PWA composite microsphere with different hierarchical surface structures could be obtained by controlling the weight ratio of APDDAB to PAM microgels, cross-linking degree of PAM microgels, the amount of PWA reacted with APDDAB in PAM/APDDAB, and solvent-washing process. Although the surface morphologies of the composite microspheres in detail were different, a general feature was of the core-shell structure and the wrinkly surface covered with APDDAB-PWA particles. The formation of the wrinkly surface is attributed to the difference in shrink between inside and outside of PAM microgel frameworks, and the formation of APDDAB-PWA small particles originates from the reaction between APDDAB aggregation and PWA. This composite microsphere with PAM hydrogel core is suitable to store water-soluble substances, and the shell composed of the surfactant/Keggin-type polyoxometalate complexes is not only amphiphilic but also catalytic. Additionally, PAM/APDDAB-PWA composite microspheres with big size and APDDAB-PWA particles with small size make the composite microspheres not only easy for separation but also beneficial for catalysis. These properties have been verified by the application of PAM/APDDAB-PWA composite microspheres to the deep desulfurization of fuel oil. This material provides an example to construct microreactors with new structure used in diphase catalytic reaction.
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