Electrosynthesis of nanofibers and nano-composite films

Abstract

A method for producing an array of oriented nanofibers that involves forming a solution that includes at least one electroactive species. An electrode substrate is brought into contact with the solution. A current density is applied to the electrode substrate that includes at least a first step of applying a first substantially constant current density for a first time period and a second step of applying a second substantially constant current density for a second time period. The first and second time periods are of sufficient duration to electrically deposit on the electrode substrate an array of oriented nanofibers produced from the electroactive species. Also disclosed are films that include arrays or networks of oriented nanofibers and a method for amperometrically detecting or measuring at least one analyte in a sample.

Description

STATEMENT OF GOVERNMENT SUPPORT [0001] This invention was made with United States Government support under Contract DE-AC0676RL01830 awarded by the U.S. Department of Energy. The Unites States Government has certain rights in the invention.FIELD [0002] The present disclosure relates to the synthesis of nanofibers and films made from the nanofibers. BACKGROUND OF THE DISCLOSURE [0003] Many methods have been reported for preparing oriented nanostructures, but most of these methods cannot be applied to organic polymer materials. Oriented carbon nanotubes are prepared through chemical vapor deposition (CVD). Large arrays of oriented carbon nanotubes were grown from catalyst particles immobilized on porous silica or glass substrates (Li et al., Science, 274, 1996; and Ren et al., Science, 282, 1150, 1998). A gas phase reaction or similar high temperature reactions have been used to prepare oriented nanorods of ZnO (Huanh et al., Science, 292, 1897, 2001), Si (Yu et al., Physica. E., 9, 3...

AI Technical Summary

Benefits of technology

The patent describes methods for controlling the growth of nanostructures, specifically the production of an array of oriented nanofibers. The methods involve depositing a solution containing electroactive species onto an electrode substrate and applying a current to the substrate for a first period of time to deposit seed nuclei of an electroactive polymer, followed by a second period of time to grow the polymer nanofibers from the seed nuclei. The resulting nanofibers have a uniform cylindrical shape and are oriented in a specific direction. The patent also describes the use of the nanofibers in the production of films and devices, such as chemical or biological sensors, and in the separation of cesium ions from a mixture. The technical effects of the patent include improved control over the growth of nanostructures and the production of uniform and oriented nanofibers.

Problems solved by technology

Many methods have been reported for preparing oriented nanostructures, but most of these methods cannot be applied to organic polymer materials.

Electrodes formed from films of hexacyanometallates have been made, but their instability and electrical properties remains a critical issue.

At such large overpotentials, substances present in biological samples such as ascorbic acid, uric acid and acetaminophen interfere under oxidation conditions, while oxygen, benzoquinone, and nitrobenzene interfere at such reduction potentials.

Low selectivity, therefore, is a major limitation in amperometric determinations.

In the sensors described by Garjonyte et al. and Karyakin et al. the Prussian blue sensing sites are only accessible by the analyte on a two-dimensional electrode surface and, thus, miniaturization of the sensor is difficult due to the limited total sensing surface area.

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