Self-assembly of Nafion molecules onto silica nanoparticles formed in situ through sol–gel process

Pan, Jingjing; Zhang, Haining; Pan, Mu

doi:10.1016/j.jcis.2008.07.010

Cited by 24 publications

(14 citation statements)

References 33 publications

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“…After adjusting the pH of the dispersion to ∼ 2.0 using 2 M HCl solution, the mixture was continuously stirred for 8 h at 40°C and a clear sol containing hybrid Nafion‐titania nanoparticles was obtained. Unless otherwise stated, the final concentration of Nafion is about 2 wt % based on our previous results 15, 16…”

Section: Methodsmentioning

confidence: 99%

Nafion^®—titania nanocomposite proton exchange membranes

Xiao

et al. 2010

J of Applied Polymer Sci

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Proton exchange membranes consisting of Nafion V R and crystallized titania nanoparticles have been developed to improve water-retention and proton conductivity at elevated temperature and low relative humidity. The anatase-type titania nanoparticles were synthesized in situ in Nafion solution through sol-gel process and the size of the formed titiania nanoparticles is in the range of 3-6 nm. The formed nanoparticles are well-dispersed in Nafion solution at the titania concentration of 5 wt %. The glass transition temperature of the formed Nafion-titania composite membrane is about 20 o C higher than that of plain Nafion membrane. At elevated temperature (above 100 C), the Nafion-titania nanocomposite membrane shows higher water uptake ability and improved proton conductivity compared to pure Nafion membrane.

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Section: Methodsmentioning

confidence: 99%

Nafion^®—titania nanocomposite proton exchange membranes

Xiao

et al. 2010

J of Applied Polymer Sci

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“…Low molecular weight aromatic compounds such as bisphenol A and bisphenol AF were encapsulated to the PFPS/silica nanocomposite cores to give a nonflammable characteristic even after calcination at 800 °C . Hitherto, there have been some reports on the preparative methods for Nafion/silica composites with TEOS under acidic conditions; however, the preparative methods of fluorinated polymers/silica composites with TEOS in the presence of silica nanoparticles under alkaline conditions are very limited except for our previously reported ones . We have already reported that fluoroalkyl end‐capped oligomers containing higher acidic protons such as sulfo groups in the silica nanocomposites, which were prepared by the sol–gel reactions of TEOS and silica nanoparticles in the presence of the corresponding oligomers under alkaline conditions, can exhibit no weight loss corresponding to the contents of oligomers in the composites even after calcination at 800 °C .…”

Section: Introductionmentioning

confidence: 90%

Preparation of perfluoro-1,3-propanedisulfonic acid/Nafion/silica hybrid nanoparticles-thermally stable Nafion in these silica hybrid nanoparticles even after calcination at 800 °C

Soma

Mizuguchi

Sugiya

et al. 2014

J. Polym. Sci. Part A: Polym. Chem.

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Perfluoro‐1,3‐propanedisulfonic acid (PFPS)/Nafion/silica hybrid particles were prepared by the sol–gel reactions of PFPS with tetraethoxysilane and silica nanoparticles in the presence of Nafion under alkaline conditions. These obtained composites exhibited a good dispersibility and stability in not only water but also traditional organic media such as methanol, ethanol, 1,2‐dichloroethane, tetrahydrofuran, and dimethyl sulfoxide. Dynamic light scattering measurements and field‐emission scanning electron microscopy show that these hybrid particles are nanometer size‐controlled fine particles before and even after calcination at 800 °C. Nafion/silica hybrid nanoparticles were also prepared in the absence of PFPS under similar conditions. The weight of original Nafion markedly dropped around 350 °C and decomposed gradually, reaching 0% around 450 °C, and Nafion in the Nafion/silica nanocomposites exhibited a similar weight loss behavior to that of the original one. However, Nafion/PFPS/silica hybrid nanoparticles were found to exhibit no weight loss corresponding to the contents of Nafion and PFPS in the silica gel matrices even after calcination at 800 °C. It was demonstrated that the pH value (3.77 at 25 °C) of Nafion/PFPS/silica hybrid nanoparticles after calcination is smaller than that (5.66 at 25 °C) before calcination, and this hybrid nanoparticles exhibited a higher proton conductivity (5.8 × 10−3 S/cm at 85 °C) than that (4.1 × 10−3 S/cm at 85 °C) before calcination. In addition, Nafion/PFPS/silica hybrid nanoparticles after calcination at 800 °C were applied to the Friedel‐Crafts acylation of thiophene with acetic anhydride to give the expected 2‐acetylthiophene, of whose yield was similar to that before calcination under similar conditions. These findings suggest that Nafion in PFPS/silica hybrid nanoparticle cores should exhibit a nonflammable characteristic even after calcination at 800 °C to act as an effective acid catalyst. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014, 52, 1869–1877

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“…The structure around Si can be represented by a tetrahedron whose corners link to other tetrahedra. The Q n notation serves to describe the substitution pattern around a specific silicon atom, with Q representing a silicon atom surrounded by four oxygen atoms and n indicating the connectivity [83]. Figure 14 presents the NMR spectrum of the sample dried at 50°C.…”

Section: Preparation Of Biomaterials By the Non-hydrolytic Sol-gel Prmentioning

confidence: 99%

Biomaterials and Sol–Gel Process: A Methodology for the Preparation of Functional Materials

Nassar¹,

Ciuffi²,

Calefi³

et al. 2011

Biomaterials Science and Engineering

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Self-assembly of Nafion molecules onto silica nanoparticles formed in situ through sol–gel process

Cited by 24 publications

References 33 publications

Nafion^®—titania nanocomposite proton exchange membranes

Nafion^®—titania nanocomposite proton exchange membranes

Preparation of perfluoro-1,3-propanedisulfonic acid/Nafion/silica hybrid nanoparticles-thermally stable Nafion in these silica hybrid nanoparticles even after calcination at 800 °C

Biomaterials and Sol–Gel Process: A Methodology for the Preparation of Functional Materials

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Self-assembly of Nafion molecules onto silica nanoparticles formed in situ through sol–gel process

Cited by 24 publications

References 33 publications

Nafion®—titania nanocomposite proton exchange membranes

Nafion®—titania nanocomposite proton exchange membranes

Preparation of perfluoro-1,3-propanedisulfonic acid/Nafion/silica hybrid nanoparticles-thermally stable Nafion in these silica hybrid nanoparticles even after calcination at 800 °C

Biomaterials and Sol–Gel Process: A Methodology for the Preparation of Functional Materials

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Nafion^®—titania nanocomposite proton exchange membranes

Nafion^®—titania nanocomposite proton exchange membranes