Structured oligo(aniline) nanofilms via ionic self-assembly

Abstract

Conducting polymers have shown great potential for application in electronic devices. A major challenge in such applications is to control the supramolecular structures these materials form to optimise the functionality. In this work we probe the structure of oligo(aniline) thin films (of subµm thickness) drop cast on a silicon substrate using synchrotron surface diffraction. Self-assembly was induced through doping with an acid surfactant, bis(ethyl hexyl) phosphate (BEHP), resulting in the formation of well-ordered lamellae with the d-spacing ranging from 2.15 nm to 2.35 nm. The exact structural characteristics depended both on the oligomer chain length and film thickness, as well as the doping ratio. Complementary UV/Vis spectroscopy measurements confirm that such thin films retain their bulk electronic properties. Our results point to a simple and effective ionic self-assembly approach to prepare thin films with well-defined structures by tailoring parameters such as the oligomer molecular architecture, the nanofilm composition and the interfacial roughness.

Hydrophilic nanoparticles stabilising mesophase curvature at low concentration but disrupting mesophase order at higher concentrations

“…1b): such as the alpha phase (L a ), also known as the fluid phase with splayed flexible tails; the ripple phase (P b ) with an undulated surface; and the crystalline phase (L c ) with compact and rigid hydrocarbon tails. The size of the domains (characterised by the coherence length) and the d-spacing fluctuations can both contribute to the broadening of the intensity peaks at different diffraction orders obtained in scattering experiments; [15][16][17] the larger the domain size and the smaller the d-spacing fluctuations, the smaller the full width at half maximum (FWHM) of the peaks, thus the bigger the coherence length, and the more highly ordered the mesophase sample is. The inverse mesophase structures with a negative curvature are typically denoted with a subscript ''II'', and these include e.g.…”

Conjugated compounds in supramolecular informational systems: A review

“…Introduction of additives of fluorescent or phos phorescent dyes into polymeric films of varying thick ness and structural organization, as alternative to covalent linkage of acceptors, has remained an object of increased attention from researchers for many years [276][277][278][279][280][281]. For example, doping of polyphenylvinylen (PPV) with a small amount of porphyrin [282] or boron dye [283] leads to sensitized emission of guest molecules, which is a consequence of transfer of energy usually occurring with a very high efficiency.…”

Insitu X-ray reflectivity studies of molecular and molecular-cluster intercalation within purple membrane films

“…The incident angle q i was varied in the range 0.06-2 for each of the measurements, corresponding to a momentum transfer Q ¼ 4p sin q i /l range of 0.011-0.345Å À1 . The surface scattering data were collected by X-ray reectivity (XRR), [19][20][21]24,25 using an avalanche photodiode detector in the specular reection plane, but at reection angles q f with a small offset Dq ¼ 0.06 (q f ¼ q i AE Dq) to the incident angle (q i ) to minimise the contribution from the silicon substrate. PM samples on solid silicon substrates were mounted inside a small chamber enclosed with Kapton lms, which allowed a constant ow of helium (He) during the measurements to reduce background scattering and sample damage.…”

“…6 From tting the Bragg peaks with a Gaussian function, the coherence length, L, of the ordered domains in the lm was calculated using the Scherrer equation, L ¼ 2pK/DQ, where DQ is the full width at half maximum (FWHM) of the peak and K is a shape factor of order unity. [24][25][26] Such Table 1.…”