Heidi Österholm

On the molecular recognition and associations between electrically conducting polyaniline and solvents

The specific interactions between sulphonic acid protonated polyaniline (PANI) and solvents are here studied both by the semiempirical AM1 method and experimentally. Phenolic solvents are shown to have a relatively large interaction with the sulphonate anions of the counterions and with the amines in PANI. In addition, a properly functionalized counterion may form cyclic associations provided that there is a steric match between the molecules concerned. This concept is called molecular recognition and it is a novel concept in the context of PANI. For example, the carbonyl group in (±)‐10‐camphor sulphonic acid (CSA) can form a hydrogen bond to the hydroxyl group of m‐cresol, whereby the phenyl ring becomes coplanar with one of the PANI rings thus enabling enhanced van der Waals interaction. This additional specific interaction agrees with our observed increased solubility with CSA doped PANI in m‐cresol, compared to its solubility in dimethyl sulphoxide or chloroform, or to tosylene sulphonic acid doped P...

Processible polyaniline complexes due to molecular recognition: Supramolecular structures based on hydrogen bonding and phenyl stacking

Abstract We show that sulphonic acid doped polyaniline (PANI) can be plasticized using certain low-acidic organic compounds consisting of ring structures and hydrogen bonding moieties that are able to “recognize” the complementary moieties of the doped PANI. The achieved synergistic combination of interactions consists of phenyl stacking, hydrogen bonding and charge transfer due to protonation. Fusible electrically conducting supramolecular structures are rendered, as suggested also by quantum chemical calculations. For example, PANI doped by methanesulphonic acid, toluenesulpnonic acid, dodecylbenzenesulphonic acid, or camphorsulphonic acid can be plasticized by dihydroxybenzenes and bisphenols to obtain fusible particle-free films at the resolution of optical microscope. The generalization to other plasticizers and other aromatic polymers, such as polypyrrole, is obvious.

TEM and WAXS characterization of polyaniline/PP fibers

Abstract PANIPOL ™ / polypropylene (PP) blends can be melt spun into conducting fibers, with a diameter of ca. 20μm. They have been characterized by TEM and WAXS. We find that the fibers have a highly ordered polyaniline (PANI) structure and exhibit a phase separated morphology with continuous fibrils of PANI in the PP-matrix. The PANI phase has a well developed three dimensional order with a layer structure parallel to the PANT chains and the fiber axis. The layer distance is ~2.9 nm as observed from the micrographs and from the low angle X-ray reflection. The presence of higher order X-ray reflections and the narrow peak width indicate long range order of ~13 nm. The continuous PANT phase gives rise to an electrical conductivity of up to 10 −3 S/cm.

Stretch-oriented poly(3-alkylthiophenes)

Abstract Poly(3-octylthiophene) has been stretched up to 5 times its original length. The state of orientation of stretch-oriented, free-standing films have been characterized by infra-red dichroism measurements and x-ray diffraction. The results shows that the crystalline regions are much more oriented than the amorphous regions. The x-ray diffraction pattern of the stretched films is also used in a discussion of the crystal structure of poly(3-octylthiophene). Furthermore, the optical anisotropy of oriented poly(3-octylthiophene) was studied by using thin films stretched on a polythylene substrate. The intrinsic anisotropy of poly(3-octylthiophene) was estimated to be around 10.

On the way to improve cetane number in diesel fuels: Ring opening of decalin over Ir-modified embedded mesoporous materials

Embedded materials prepared from MCM-41 together with BE or TON were synthesized, characterized and tested in the ring opening of decalin in a temperature range of 523–623 K. The characterization results revealed that both microporous and mesoporous phases were present in the catalyst. Ir-modification did not change the phase purity, affecting, however, the acidity due to metal-support interactions. The parameters studied in ring opening of decalin were support structure, presence of Ir and temperature. The detailed analysis of 2D/3D isomers and ring opening products showed that the main ring opening products contained ethyl side chain. The Ir-modified embedded mesoporous catalysts were active and relatively selective in the ring opening of decalin, giving 35% selectivity to the ring opening products at 98% conversion at 573 K and 6 MPa.

Deposition of platinum into beta-zeolite

Abstract Platinum was deposited into beta zeolites with different techniques. Platinum was well-dispersed when the catalyst was prepared by ion exchange and Atomic Layer Epitaxy (ALE) deposition methods. In impregnation, the source material of platinum and post-treatments affected for the dispersion. Platinum dispersion was low when trimethyl(methylcyclopentadienyl)platinum impregnated beta zeolite was calcined prior to reduction. In calcination at 623 K in air most platinum was reduced. Platinum was totally reduced with hydrogen at 573 K. In pulsing of carbon monoxide at 300 K on platinum ALE catalyst, carbon dioxide formation was observed. Trimethyl(methylcyclopentadienyl)platinum impregnated beta zeolite produced selectively cinnamyl alcohol at low conversion whereas with other catalysts several different products were formed.