Design of a versatile chemical assembly method for patterning colloidal nanoparticles

Abstract

Poly(methyl methacrylate) (PMMA) domains in phase-separated polystyrene-b-poly(methyl methacrylate) (PS-b-PMMA) diblock copolymer thin films were chemically modified for controlled placement of solution synthesized Au nanoparticles having a mean diameter of 24 nm. Colloidal Au nanoparticles functionalized with thioctic acid were immobilized on amine functionalized PMMA domains on the PS-b-PMMA template using 1-ethyl-3-[3-dimethylaminopropyl] carbodiimide hydrochloride linking chemistry and N-hydroxy sulfosuccinimide stabilizer. Atomic force microscopy and scanning electron microscopy images demonstrated immobilization of Au nanoparticles commensurate with PMMA domains. Nanoparticles form into clusters of single particles, dimers, and linear chains as directed by the PMMA domain size and shape. Capillary forces influence the spacing between Au nanoparticles on PMMA domains. Inter-particle spacings below 3 nm were achieved and these assemblies of closely spaced nanoparticle clusters are expected to exhibit strong localized electromagnetic fields. Thus, these processes and material systems provide an experimental platform for studying resonantly enhanced excitations of surface plasmons as a function of material and geometric structure as well as utilization in catalytic applications.

Comparison of electric field enhancements: Linear and triangular oligomers versus hexagonal arrays of plasmonic nanospheres

“…We then perform full-wave simulations of selected fabricated clusters of nanospheres with the aim of demonstrating the formation of field hot spots in experimentally achievable systems. In previous work, we have found Au nanoparticle oligomers are influenced by the shape of the chemical domain [25]. Thus integrating the chemical assembly process referred to here with ordered diblock copolymer surfaces [26][27][28] is a promising approach for selecting between triangular type oligomers and linear oligomers.…”

“…The substrates have a thin film of polystyrene-block-poly(methyl methacrylate), PS-b-PMMA, on its surface where PMMA regions are functionalized with primary amine groups using ethylenediamine/dimethylsulfoxide (ED/DMSO) solution [24]. 1-Ethyl-3-[3-dimethylaminopropyl] carbodiimidehydrochloride (EDC), via coordination cross-linking chemistry with N-hydroxysulfosuccinimide (S-NHS), was then used to anchor the Au nanospheres onto functionalized PMMA domains [25]. A scanning electron microscopy (SEM) image of a fabricated sample is shown in Fig.…”

Directing Cluster Formation of Au Nanoparticles from Colloidal Solution

“…Citrate stabilized colloidal Au nanoparticles of 10 nm diameter (and colloidal Ag nanoparticles of 20 nm diameter) were purchased in 0.01 wt % aqueous solution to maintain consistent particle size. This Au nanoparticle solution was functionalized with TA after replacing the solvent with pH 11.67 dilute NaOH solution as previously reported in Choi et al 30 The 10 nm Au nanoparticles were functionalized with TA at concentration 0.25 mM. For both types of nanoparticles, the residual TA was removed from the nanoparticle solution and the basicity reduced to pH 8 by centrifuging at 7000g for 20 min for 20 nm Au nanoparticles and 65000g for 50 min for 10 nm Au nanoparticles.…”

Nanolipodendrosome-loaded glatiramer acetate and myogenic differentiation 1 as augmentation therapeutic strategy approaches in muscular dystrophy

“…Thus, the N-Sulf-HS was used as a water sensitivity reducer. 13 Additionally, EDC was used as the catalyst (activator of the carboxyl groups). The pH of the testing environment was 7.2 to7.3 and the time required for the reaction was 1 day.…”