Journal of Materials Chemistry Blog

A perfluorinated anion exchange membrane with a 1,4-dimethylpiperazinium cation demonstrated enhanced hydroxide ion conductivity.

The membrane also exhibited a better water uptake than a typical hydrocarbon anion exchange membrane with the same cation. When tested, the membrane showed a remarkable stability of over 30 days in 2 M KOH at 60 °C and good fuel cell performance. Work is ongoing to investigate the attachment of more basic cations to further enhance the hydroxide ion conductivity, fuel cell performance and long term stability.

Interested to know more? Why not read the full article for free: M.-s. J. Jung, C. G. Arges and V. Ramani, J. Mater. Chem., 2011, DOI: 10.1039/c1jm10320b

Researchers from Bar-Ilan University have developed novel hybrid silica nanoparticles (NPs) with highly photoreactive sites on their surface by incorporation of phenyl azide (PA) or benzophenone (BPh) functionality.

It is found that, in contrast to what is stated in the literature, SiO₂@PA NPs are much more reactive than SiO₂@PFPA ones in solid state photochemical reactions. Additionally, this is the first report of covalent immobilization of NPs into biocompatible parylene C films to form hydrophilic and functional composite films. Amine functionality has also been introduced onto the silica NPs by reaction with APTES. This approach could open up new possibilities for simple and solvent-free functionalization of materials by light.

Interested to know more? Why not read the full article for free: A. Peled, M. Naddaka and J.-P. Lellouche, J. Mater. Chem., 2011, DOI: 10.1039/c1jm00055a

Researchers in Germany have achieved metal ion release from a silicone matrix by an electrochemistry-controlled method.

Synergistic metal ion release from a silicone matrix filled with silver and copper as well as silver and gold nanoparticles (NPs) was investigated. It was found that silver NPs enhanced the release of copper ions, whereas gold NPs did not enhance the release of silver ions. The mechanism of the release of the less noble metal nanoparticles is based on ion-mediated electrochemistry and not contact corrosion of both elements. This work shows potential in the design of time- and rate-controlled bioactive nanocomposites.

Interested to know more? Why not read the full article for free: A. Hahn, S. Günther, P. Wagener and S. Barcikowski, J. Mater. Chem., 2011, DOI: 10.1039/c0jm04480f (Advance Article)

Collaborative research from Japan and Canada has shed light on the type and mechanism of conductance of individual WO₃ nanowire FETs.

Individual WO₃ nanowire photodetectors were shown to hold great potential as UV-A light sensors. By fabricating these sensors on carbon paper, significantly enhanced stability and shortened response and decay times were obtained. The WO₃ nanowires were also subjected to field-emission measurements and the results showed that these nanostructures are promising candidates for incorporation into novel electronic and optoelectronic devices.

Interested to know more? Why not read the full article for free: L. Li, Y. Zhang, X. Fang, T. Zhai, M. Liao, X. Sun, Y. Koide, Y. Bando and D. Golberg, J. Mater. Chem., 2011, DOI: 10.1039/c0jm04557h (Advance Article)

A new method to rationally design and fabricate silica ridge optical waveguides in a simple, cost-effective manner has been developed by researchers from the Republic of Korea and USA.

This new method is based on the controlled evaporative self-assembly of a polymer solution constrained in a cylinder-on-flat geometry with subsequent wet and dry etching of the sacrificial Ni–Cr film, polymer template and silica layer. Waveguides made in such a way may find potential applications as optical sensors.

Interested to know more? Why not read the full article for free:  S. W. Kwon, M. Byun, D. H. Yoon, J.-H. Park, W.-K. Kim, Z. Lin and W. S. Yang, J. Mater. Chem., 2011, DOI: 10.1039/C0JM04514D (Advance Article)

Researchers from Ben-Gurion University of the Negev and University of Maryland Baltimore County have shown that mixed metal substrates made from aluminium and silver nanodeposits can enhance luminescence.

This enables enhanced luminescence from UV protein residues, solvents and traditional visible fluorophores. The wavelength enhancement range is much broader than silver alone and other metal enhanced fluorescence (MEF) substrates reported thus far. These results indicate that mixed metal surfaces are a better choice for MEF applications than the customary single metal surfaces. Films made in such a way could prove to be very useful for various biomedical assays that utilise fluorescence.

Interested to know more? Why not read the full article for free: K. Golberg, A. Elbaz, Y. Zhang, A. I. Dragan, R. Marks and C. D. Geddes, J. Mater. Chem., 2011, DOI: 10.1039/C0JM04311G (Advance Article)

Researchers from University of Virginia have investigated the effects of aromatic substituents in boron diketones.

All of the dyes studied except BF₂mbm (i.e. those with aromatic rather than aliphatic substitution) showed emission changes upon mechanical perturbation. Aromatics with increased π conjugation led to more dramatic, red-shifted fluorescence. Their recovery is also significantly affected by the aromatic substituents.

Interested to know more? Why not read the full article for free:  T. Liu, A. D. Chien, J. Lu, G. Zhang and C. L. Fraser, J. Mater. Chem., 2011, DOI: 10.1039/c0jm04326e (Advance Article)

Researchers at Nanyang Technological University have synthesised organic single crystals with thicknesses ranging from a few monolayers to micrometres by an “Organic Crystal Cleavage” method.

Ultrathin F₁₆CuPc and pentacene single crystal field-effect transistors were subsequently fabricated and the corresponding thickness dependence of mobility was investigated. The charges induced in the metal–semiconductor interface reduced the contact barrier. This, in turn, allowed measurement of the values of mobility that precisely reflected the real transport properties of organic semiconductors.

Interested to know more? Why not read the full article for free: H. Jiang, K. Jie Tan, K. K. Zhang, X. Chen and C. Kloc, J. Mater. Chem., 2011, DOI: 10.1039/c0jm04383d (Advance Article)

The thermal conductivities of blend-PI films containing ZnO nanoparticles have been investigated by researchers from Tokyo Institute of Technology for future electric and electronic applications.

The blend films obtained were composed of sulfur- and fluorine- containing PIs and exhibited distinct microphase-separated structures with a vertical double percolation morphology. These films had two principle advantages over conventional homo-PI systems. The smaller ZnO content in the blend-PI films conferred a larger thermal conductivity. Additionally, the thermal conductivity was larger in pristine (without ZnO nanoparticles) blend-PI films than homo-PI films. A higher thermal conductivity is advantageous for application in polymer dielectric materials, as it allows for better flexibility, light weight and higher electric insulation properties.

Interested to know more? Why not read the full article for free: D. Yorifuji and S. Ando, J. Mater. Chem., 2011, 21, 4402.

Researchers from Georgia Institute of Technology and University of Washington have synthesised dithienopyrrole–quinoxaline/pyridopyrazine donor–acceptor polymers by Stille coupling reactions.

It was found that the pyridopyrazine moiety is a stronger acceptor than quinoxaline and that the extended benzophenazine and dibenzopyridoquinoxaline species are stronger acceptors than quinoxaline and pyridopyrazine, respectively. When used in field effect transistors, average hole mobilities of up to ca 3.0 × 10^–4 cm² V^–1 s^–1 were obtained. Bulk heterojunction photovoltaic devices made from blends of the benzo[a,c]phenazine-based polymer gave average power conversion efficiencies of 1.4%.

Interested to know more? Why not read the full article for free: X. Zhang, J. W. Shim, S. P. Tiwari, Q. Zhang, J. E. Norton, P.-T. Wu, S. Barlow, S. A. Jenekhe, B. Kippelen, J.-L. Brédas and S. R. Marder, J. Mater. Chem., 2011, DOI: 10.1039/c0jm04290k (Advance Article)