Fabrication of Ordered Catalytically Active Nanoparticles Derived from Block Copolymer Micelle Templates for Controllable Synthesis of Single-Walled Carbon Nanotubes

Abstract

We report the use of the block copolymer micelle approach to produce various transition metal nanoparticles such as iron, cobalt, and nickel with precisely controlled size and spacing. These uniformly sized catalyst nanoparticles derived from the block copolymer micelle approach have enabled the synthesis of carbon nanotubes (CNTs) with narrow size distribution. Because of the excellent film forming ability of the polymeric material, metal-bearing surface micelles produced from the solution micelles can be distributed uniformly on a surface, resulting in evenly dispersed catalyst nanoparticles. As a result, high quality and uniformly distributed CNTs have been synthesized. Spatially selective growth of CNTs from a lithographically patterned metal-bearing micelle film has been achieved. The polymer template approach can potentially be extended to synthesize single-metallic and bimetallic catalytically active nanoparticles with uniform size and spacing and is fully compatible with conventional lithographic process. Additionally, catalyst nanoparticles produced from this method do not coalesce at high growth temperature. All these attributes make this approach a promising fabrication pathway for controllable synthesis of CNTs.

Role of catalysts in the surface synthesis of single-walled carbon nanotubes

“…However, in order to obtain highly efficient growth of SWNTs with uniform diameters on surfaces, both exact control of the size of catalyst nanoparticles and choice of a proper feeding rate of carbon are necessary. There are a considerable number of papers presenting methods to control the size of catalyst nanoparticles, including direct synthesis of monodisperse nanoparticles by thermal decomposition of metal carbonyl complexes [7], by using metal-containing proteins [9, 10], polymers, and identical molecular nanoclusters as catalyst precursors [11, 13 15], and by using block copolymer micelles [38] or dendrimers [8] as synthetic templates for catalyst nanoparticles. Furthermore, it has been shown that the presence of polymers in the catalyst precursors not only contributes to the synthesis of monodisperse catalyst nanoparticles, but also can effectively prevent the aggregation of catalyst particles on the surface during the process of solvent evaporation.…”

“…For example, selfassembled block copolymer micelles were found to be good templates for tuning the spacing between catalyst nanoparticles on silicon wafers (Fig. 3, where AFM is atomic force microscopy; SEM is scanning electron microscopy) [38]. Another function of some photosensitive polymers is to fabricate catalyst patterns on the substrates and thus afford ordered structures of SWNTs on chips (Fig.…”

Synthesis of Quasi‐Hexagonal Ordered Arrays of Metallic Nanoparticles with Tuneable Particle Size

“…

Noble-metal nanoparticles (Au, Ag, Pt, Pd) are of substantial interest for various scientific and technical applications [1] because they exhibit a number of unique optical, [2][3][4] electronic, [5,6] and catalytic [7,8] characteristics compared to bulk materials. It is important to realize that nearly all of these properties are a function of the particle size and shape at the nanometer scale.

The size-dependent interaction of light with small particles, referred to as localized surface-plasmon resonance (LSPR), [9] and coupled-plasmon resonance [10] enables them to be used for various applications such as biosensors [11] and molecular rulers.

…”

Controllable fabrication of carbon nanotubes on catalysts derived from PS-b-P2VP block copolymer template and in situ synthesis of carbon nanotubes/Au nanoparticles composite materials

“…Chemical vapor deposition (CVD) is the most widely used method for its easy of operation and the CNTs are grown selectively on catalytic sites. Therefore, the diameter, location, and density of CNTs are thus largely dependent on the size, placement, and interparticle distance of catalyst nanoparticles [7,8]. In the traditional CVD method, a metal thin film is first deposited on a surface using magnetron sputtering, then at high temperature, the film breaks apart and forms the metal particles as the catalyst for CNTs growth [9,10].…”