Layers of Polyaniline Nanotubes Deposited by Langmuir–Blodgett Method

Abstract

The Langmuir−Blodgett (LB) method has long been used for the preparation of ultrathin films, offering the unique control over the film thickness and the molecular orientation. Here, we report on the deposition and the characterization of LB layers of polyaniline (PANI) nanotubes on solid supports. Stable suspension of the nanotubes in chloroform was obtained by adding sodium dodecyl sulfate (SDS). The nanotubes to SDS ratio is important for the stability of the suspension. Langmuir films were spread at the water/air interface and transferred on gold or ITO glass substrate. The electroactivity of obtained films was investigated using cyclic voltammetry. The degree of assembly of the PANI nanotubes in thin films was characterized by optical microscopy and scanning electron microscopy (SEM). To evaluate the molecular structure and the PANI oxidation state, UV−vis and Raman mapping were used. The PANI nanotube films on the gold support are electroactive with cyclic voltammetry responses closely resembling typical PANI layers. Raman maps reveal that the spatial distributions of SDS and PANI bands are identical, suggesting that only detergent molecules bond to nanotubes are transferred on the support.

Nanoforest: Polyaniline Nanotubes Modified with Carbon Nano-Onions as a Nanocomposite Material for Easy-to-Miniaturize High-Performance Solid-State Supercapacitors

“…For comparison, the specific capacity for a PANI nanofiber-modified electrode obtained in the same acid solution in the presence of an ammonium persulfate oxidant, was determined to be 235 F g −1 [17]. The above-mentioned methods enable one to realize randomly aggregated granules, nanoroughened polymer hydrophobic surfaces, nanospheres surrounded by surfactant molecules, nanofibers, or nanotubes inside the membrane matrix [18].…”

Mechanisms of polyaniline film formation via solution casting: Intra-chain contraction versus inter-chain association

“…For example, it is well-known that an expanded-coil conformation of doped PANI molecules leads to increased infrared absorption in the electronic spectrum, it also improves mechanical properties and increases electrical conductivity of the film as compared with the film where the molecules are in the compact-coil conformation [1]. In order to provide a required structural organization of a polymer film, various deposition techniques can be employed, such as chemical and electrochemical deposition onto specific substrates [2], spin-and drop-casting [3,4], Langmuir-Blodgett [5][6][7], self-assembly [8][9][10], grafting to the surface [11,12], and molecular imprinting [13]. While many techniques provide more or less controlled structure of PANI films, casting from a solution still leads to ambiguous results in respect to the film structure, since the nature of a cast film depends critically on the relative rate of solvent evaporation in respect to the rate at which changes in molecular interaction occur.…”

Dynamics of roughening and growth kinetics of CdS–polyaniline thin films synthesized by the Langmuir–Blodgett technique

“…The variation in structural and morphological properties of the multilayer lms can be studied as a shi of thickness from the nanoregion to the mesoscopic stage. [19][20][21] The layer-by-layer fabrication leads to specic top surfaces with variation in interfacial roughness. Most of the rough surfaces exhibit signicant selfaffine properties upto a certain range of length scale.…”