Synthesis of Copper Nanocatalysts with Tunable Size Using Diblock Copolymer Solution Micelles

Abstract

Self-assembled solution micelles prepared from polystyrene-b-poly(4-vinylpyridine) (PS-b-P4VP) and polystyrene-b-poly(2-vinylpyridine) (PS-b-P2VP), have been employed as templates to synthesize copper nanocatalysts which are regarded as an excellent catalyst system for 1D nanomaterial synthesis. We have demonstrated that uniform-sized nanoparticles with diameters ranging from 1 to 15 nm have been generated. We have revealed that nanocatalyst size can be rationally tailored by adjusting the interaction between copper precursors and ligands and metal sequestration time. Ordered arrays of copper nanocatalysts derived from depositing a monolayer of solution micelles exhibit excellent thermal stability and do not agglomerate during the thermal treatment at 850°C, typical growth temperature for 1D nanomaterial using the chemical vapor deposition technique. High-density and aligned single-walled carbon nanotubes with uniform diameter have been synthesized using the chemical vapor deposition technique. The average diameter is 1.4 nm, which is on the same order of catalyst size, around 2.0 nm. The combination of tunable size and spacing with superb thermal stability and outstanding catalytic activity offered by this new copper nanocatalyst system will enable growth of high-yield 1D nanomaterials with controllable diameter and spacing consistently and reproducible properties. It also paves a new path to study the effect of nanocatalyst size on 1D nanomaterial synthesis and their properties.

Directed self-assembly of PS-b-PMMA block copolymer using HSQ lines for translational alignment

“…Piranha activation results in the formation of surface OH groups as can be seen from the very low water contact angle (27 ) on the substrate surface. EG solution in ethanol was spincoated on the activated surface and exposed in ambient conditions at room temperature ($288 K) prior to use.…”

Nanolithography through mixture of block copolymer micelles

“…Metal and semiconductor nanoparticles exhibit unique, size-dependent properties. Their technological potential in biomolecular recognition, catalysis, molecular electronics and photonics has fueled the synthesis effort [1][2][3][4][5][6][7][8][9][10]. The block copolymer template approach, regarded as a powerful nanofabrication enabler [3,11,12], offers the capacity of generating periodically ordered and uniform nanoparticles with tunable composition, size, and spacing simultaneously at low cost and high throughput.…”

Facile One‐Pot Synthesis of Functional Gold Nanoparticle–Polymer Hybrids Using Ionic Block Copolymers as a Nanoreactor

“…The synthesis of well‐ordered hybrid materials with small and uniform metal NPs is one of the most important challenges to stimulate synergetic effects, i.e., catalytic and optoelectronic properties. The most often chosen method is the in situ synthesis of the NPs within the polymer matrix because the existence of the polymer matrix dramatically limits the size of the NPs 4…”

“…Amphiphilic block copolymers5 have been considered as an ideal choice since the hydrophilic domains of the self‐assembled microstructures can serve as a confined reaction vessel to synthesize metal NPs. The commonly used amphiphilic block copolymers for the synthesis of metal NPs are poly(styrene‐ block ‐ethylene oxide) (PS‐ b ‐PEO),6 poly(styrene‐ block ‐vinyl pyridine) (PS‐ b ‐P4VP or PS‐ b ‐P2VP),4c, 5a, 7 and poly(styrene‐ block ‐methyl methacrylate) (PS‐ b ‐PMMA) 8. Many different approaches have been carried out and the key parameters to control the size of the NPs are known to be the reduction rate of the metal ions5a and/or the molecular weight of the block copolymers 9…”

“…The ionic sites have an ability to provide ionic conductivity, and electronic conductivity can be achieved if an interconnected network of metal NPs is created. The most widely studied ionic block copolymers are poly(styrene‐ block ‐acrylic acid) (PS‐ b ‐PAA)4b, 11e and Nafion11f where–COOH and–SO 3 H groups act as active sites for the selective sequestering of metal ions. However, it is fair to say that only limited data verifying the forte of using ionic block copolymers for functional hybrid materials have been reported.…”