Limits...
Copper nanocoils synthesized through solvothermal method.

Liu Y, Liu X, Zhan Y, Fan H, Lu Y - Sci Rep (2015)

Bottom Line: In the liquid solution, nanosprings could be formed from relaxed nanocoils and demonstrated high elasticity.Their growth and deformation mechanisms were then investigated and discussed along with that of previously reported single-turn copper nanorings.This work could be of importance for researchers working on synthesis and applications of novel 1-D helical nanomaterials and their functional devices.

View Article: PubMed Central - PubMed

Affiliation: Institute of Photonics and Photon Technology, Northwest University, Xi'an, Shaanxi, 710069, China.

ABSTRACT
Recently helical nanostructures such as nanosprings and nanocoils have drawn great interests in nanotechnology, due to their unique morphologies and physical properties, and they may be potential building blocks in sorts of electromechanical, magnetic, photoelectronic and plasmonic devices at micro/nanoscales. In this report, multi-turns copper nanocoils were synthesized through a modified solvothermal method, in which the mixture of water and N-methyl-2-pyrrolidone (NMP) were selected as reaction medium and copolymer poly(1-vinylpyrrolidone-co-vinyl acetate) (PVP/VA 64E) as reductant. In the liquid solution, nanosprings could be formed from relaxed nanocoils and demonstrated high elasticity. These nanocoils and nanosprings are of single crystalline structure, with the characteristics wire diameters ranging from tens to a few hundreds of nanometers and the ring/coil diameters mostly ~10-35 microns. Their growth and deformation mechanisms were then investigated and discussed along with that of previously reported single-turn copper nanorings. This work could be of importance for researchers working on synthesis and applications of novel 1-D helical nanomaterials and their functional devices.

No MeSH data available.


Related in: MedlinePlus

SEM images and EDS pattern of copper nanocoils.(a–c) Nanocoils with different numbers of turns. One nanocoil shown in (c) holds 8 turns and local fragments of which were shown in (d,e) at higher magnifications. (f) One EDS pattern of a typical nanocoil.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4660362&req=5

f1: SEM images and EDS pattern of copper nanocoils.(a–c) Nanocoils with different numbers of turns. One nanocoil shown in (c) holds 8 turns and local fragments of which were shown in (d,e) at higher magnifications. (f) One EDS pattern of a typical nanocoil.

Mentions: Morphologies of as-prepared samples are shown in SEM images in Fig. 1. Along with conventional copper wires and plates of nano/submicron sizes, multi-turns nanocoils can be easily and clearly found in samples. These curved nanostructures compose a considerable proportion in the final product, roughly 15% or even higher among the as-fabricated nanostructures in the solutions. Diameters of these coils are mainly in range from 10 microns to 35 microns (see size distribution in Supplementary Information), and their line widths (characteristic diameters) are from about 90 nm up to about 200 nm. In nanocoils, bent copper wires of different turns sometimes adhere to each other and form sections of compact arrangements, which can attribute to the adhesive polymer coating on nanocoils, a typical by-product formed in similar hydrothermal syntheses through a so-called “synergistic soft-hard template mechanism” (SSHM)3334. However diameters of different turns are not always uniform, which makes a complete compact arrangement around one coil impossible, so in nanocoils compact sections are accompanied by loose sections in many occasions. Careful checking the coiled nanowires in compact sections (Fig. 1d,e) shows that their arrangements can be in parallel or more compact way, do not strictly follow one single mode. Closed structure can be seen more clearly in nanocoils of fewer turns (Fig. S3, Supplementary information), and it can also be found there that not all the closed nanocoils have smoothly jointed ends. EDS pattern in Fig. 1f reveals that these nanocoils consist of copper (Cu) element, whereas the detected carbon (C) element should be mainly attributed to copolymer coating on the surface of the nanocoils. TEM analysis of nanocoils shown in Fig. 2(a,b) confirmed the near-perfect circular/multi-ring shape and uniform line widths of these nanocoils. Normally the typical line widths of nanocoils are too larger for suitable high resolution TEM imaging (HRTEM); only at edges of some thinner coils HRTEM images were made possible. Selected area electron diffraction (SAED) and localized HRTEM imaging on multiple locations along a single nanocoil was taken, such as an HRTEM image and the corresponding diffraction pattern calculated by fast Fourier transformation shown in Fig. 2c, to confirm the single-crystallinity of nanocoils (in <110> growth orientation along the wire axis). Furthermore, for nanocoils in the stock solution, in situ optical microscope observation was carried out, in which several nanocoils with non-closed ends were clearly shown in Fig. 3a,b. More interestingly, sometimes nanocoils can be relaxed and formed in multi-turn spring forms, i.e. nanosprings, as shown in Fig. 3c,d. Those nanosprings were from stretched or relaxed nanocoils in liquid environment, and such a stretching process has been evidenced in Fig. 3e,f as their intermediate state. These nanosprings demonstrated good elasticity and fatigue resistance under external mechanical disturbance (by shaking the solution or manipulated by a microprobe). However, due to the surface tension during the drying process for preparing free-standing SEM and TEM samples, different turns in nanosprings will tend to adhere to each other, becoming typical nanocoils shown in the EM images. These incompact coiled samples, and especially nanosprings in the stock solution, suggested that nanocoils are not simply bonded products of discrete single-turn nanorings, but indeed natural products of prolonged helical growth. A few other novel nanostructures, such as non-closed bent nanobelts can be also found in the solution (Fig. S4 and Fig. S5, Supplementary Information).


Copper nanocoils synthesized through solvothermal method.

Liu Y, Liu X, Zhan Y, Fan H, Lu Y - Sci Rep (2015)

SEM images and EDS pattern of copper nanocoils.(a–c) Nanocoils with different numbers of turns. One nanocoil shown in (c) holds 8 turns and local fragments of which were shown in (d,e) at higher magnifications. (f) One EDS pattern of a typical nanocoil.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4660362&req=5

f1: SEM images and EDS pattern of copper nanocoils.(a–c) Nanocoils with different numbers of turns. One nanocoil shown in (c) holds 8 turns and local fragments of which were shown in (d,e) at higher magnifications. (f) One EDS pattern of a typical nanocoil.
Mentions: Morphologies of as-prepared samples are shown in SEM images in Fig. 1. Along with conventional copper wires and plates of nano/submicron sizes, multi-turns nanocoils can be easily and clearly found in samples. These curved nanostructures compose a considerable proportion in the final product, roughly 15% or even higher among the as-fabricated nanostructures in the solutions. Diameters of these coils are mainly in range from 10 microns to 35 microns (see size distribution in Supplementary Information), and their line widths (characteristic diameters) are from about 90 nm up to about 200 nm. In nanocoils, bent copper wires of different turns sometimes adhere to each other and form sections of compact arrangements, which can attribute to the adhesive polymer coating on nanocoils, a typical by-product formed in similar hydrothermal syntheses through a so-called “synergistic soft-hard template mechanism” (SSHM)3334. However diameters of different turns are not always uniform, which makes a complete compact arrangement around one coil impossible, so in nanocoils compact sections are accompanied by loose sections in many occasions. Careful checking the coiled nanowires in compact sections (Fig. 1d,e) shows that their arrangements can be in parallel or more compact way, do not strictly follow one single mode. Closed structure can be seen more clearly in nanocoils of fewer turns (Fig. S3, Supplementary information), and it can also be found there that not all the closed nanocoils have smoothly jointed ends. EDS pattern in Fig. 1f reveals that these nanocoils consist of copper (Cu) element, whereas the detected carbon (C) element should be mainly attributed to copolymer coating on the surface of the nanocoils. TEM analysis of nanocoils shown in Fig. 2(a,b) confirmed the near-perfect circular/multi-ring shape and uniform line widths of these nanocoils. Normally the typical line widths of nanocoils are too larger for suitable high resolution TEM imaging (HRTEM); only at edges of some thinner coils HRTEM images were made possible. Selected area electron diffraction (SAED) and localized HRTEM imaging on multiple locations along a single nanocoil was taken, such as an HRTEM image and the corresponding diffraction pattern calculated by fast Fourier transformation shown in Fig. 2c, to confirm the single-crystallinity of nanocoils (in <110> growth orientation along the wire axis). Furthermore, for nanocoils in the stock solution, in situ optical microscope observation was carried out, in which several nanocoils with non-closed ends were clearly shown in Fig. 3a,b. More interestingly, sometimes nanocoils can be relaxed and formed in multi-turn spring forms, i.e. nanosprings, as shown in Fig. 3c,d. Those nanosprings were from stretched or relaxed nanocoils in liquid environment, and such a stretching process has been evidenced in Fig. 3e,f as their intermediate state. These nanosprings demonstrated good elasticity and fatigue resistance under external mechanical disturbance (by shaking the solution or manipulated by a microprobe). However, due to the surface tension during the drying process for preparing free-standing SEM and TEM samples, different turns in nanosprings will tend to adhere to each other, becoming typical nanocoils shown in the EM images. These incompact coiled samples, and especially nanosprings in the stock solution, suggested that nanocoils are not simply bonded products of discrete single-turn nanorings, but indeed natural products of prolonged helical growth. A few other novel nanostructures, such as non-closed bent nanobelts can be also found in the solution (Fig. S4 and Fig. S5, Supplementary Information).

Bottom Line: In the liquid solution, nanosprings could be formed from relaxed nanocoils and demonstrated high elasticity.Their growth and deformation mechanisms were then investigated and discussed along with that of previously reported single-turn copper nanorings.This work could be of importance for researchers working on synthesis and applications of novel 1-D helical nanomaterials and their functional devices.

View Article: PubMed Central - PubMed

Affiliation: Institute of Photonics and Photon Technology, Northwest University, Xi'an, Shaanxi, 710069, China.

ABSTRACT
Recently helical nanostructures such as nanosprings and nanocoils have drawn great interests in nanotechnology, due to their unique morphologies and physical properties, and they may be potential building blocks in sorts of electromechanical, magnetic, photoelectronic and plasmonic devices at micro/nanoscales. In this report, multi-turns copper nanocoils were synthesized through a modified solvothermal method, in which the mixture of water and N-methyl-2-pyrrolidone (NMP) were selected as reaction medium and copolymer poly(1-vinylpyrrolidone-co-vinyl acetate) (PVP/VA 64E) as reductant. In the liquid solution, nanosprings could be formed from relaxed nanocoils and demonstrated high elasticity. These nanocoils and nanosprings are of single crystalline structure, with the characteristics wire diameters ranging from tens to a few hundreds of nanometers and the ring/coil diameters mostly ~10-35 microns. Their growth and deformation mechanisms were then investigated and discussed along with that of previously reported single-turn copper nanorings. This work could be of importance for researchers working on synthesis and applications of novel 1-D helical nanomaterials and their functional devices.

No MeSH data available.


Related in: MedlinePlus