One-dimensional diamondoid polyaniline-like nanothreads from compressed crystal aniline.

Marcelo M Nobrega,Roberto Bini,Erico Teixeira-Neto,Andrew B Cairns,Marcia L A Temperini

doi:10.1039/c7sc03445h

Abstract

Low-dimensional nanomaterials such as highly ordered polyaniline (PANI) have attracted considerable interest due to their expected extraordinary electronic and optoelectronic properties. In spite of several attempts, the attainment of atomically well-ordered PANI is a long-standing challenge. Pressure-induced polymerization of aromatic molecules in the crystal phase has been demonstrated as a practicable route for the synthesis of highly ordered polymers but this approach has never been tested to produce PANI. Here we show the synthesis of diamondoid polyaniline-like nanothreads at 33 GPa and 550 K by compressing aniline in crystal phase-II. Infrared spectroscopy, transmission electron microscopy, X-ray diffraction data, and DFT calculations support the formation of this totally new polyaniline-like nanothread. The NH2-enriched carbon nanothread combines the outstanding mechanical properties of carbon nanotubes with the versatility of NH2 groups decorating the exterior of the nanothreads representing potential active sites for doping and as linkers for molecules with biological interest and inorganic nanostructures. The synergy of all of these properties emphasizes the strong potential of this material to be applied in a broad range of areas, from chemistry to materials engineering.

Highlights

The obtainment of highly-ordered low-dimensional polyaniline (PANI) is a long-standing challenge of great interest for a large part of the scienti c community
Solid-state chemistry induced at high-pressure and hightemperature has been successfully used in the search for new and fascinating materials such as con ned polymers and extended amorphous networks.[5,6,7,8,9]
Reactivity threshold of aniline at several P and T conditions, we have employed a model accounting for thermal displacements already used for s-triazine[5] and benzene[10] crystals adopting the critical distance, 2.5–2.6 Abetween the closest intermolecular

Summary

Introduction

Solid-state chemistry induced at high-pressure and hightemperature has been successfully used in the search for new and fascinating materials such as con ned polymers and extended amorphous networks.[5,6,7,8,9] A possible advantage of these reactions is represented by the topochemical constraints posed by the crystal that can give rise to products closely recalling the symmetry of the molecular crystal from which it is formed.[6,10,11] In some cases the pressure and temperature conditions required for the synthesis are such that they can be scaled up, representing a ‘green’ method appealing to industrial chemical synthesis, since the use of additional and polluting compounds such as initiators, catalysts and solvents is avoided. Transmission electron microscopy (TEM), X-ray diffraction data, and density functional theory (DFT) calculations support the formation of this totally new polyaniline nanothread

Results and discussion

Methods

Conclusions