Thermal Annealing: A Facile Way of Conferring Responsivity to Inert Alkyl-Chain-Passivated Nanoparticle Arrays

Abstract

This work demonstrates a facile post-treatment strategy, vacuum thermal annealing, to fabricate a dodecanethiol-passivated gold nanoparticle (Au NP) array with organic solvent sensitivity. Through investigating the structure change of the Au NP array, it was found that the interparticle distance decreased during vacuum heat treatment, which meant a closer arrangement of the particles and a more dense packing of the dodecanethiol ligands in the interparticle region. The condensation would increase the interaction of the alkyl chain and enhance their interdigitation. Furthermore, on the basis of the stretching of the alkyl chains in organic solvents, the thermally treated Au NP array showed a good response to organic solvent or vapor by using the interdigitated dodecanethiol network as its responsive unit. The alkyl chains stretch to different extents in different organic solvents, leading to differences in interparticle distance, which provided a distinct blue shift of maximum wavelength upon exposure to various organic solvents or vapors. All of these results indicated that thermal annealing was an efficient way to confer responsivity to inert Au NP arrays. Together with the cost-effectiveness of such NP arrays, this study has potential in the development of economical sensors for medical diagnostics, food safety screening, and environmental pollution monitoring.

A Novel Strategy for Fabricating a Strong Nanoparticle Monolayer and Its Enhanced Mechanism

“…In this scenario, offering a relatively rigid monolayer with ordered structure is necessary. We prepared a stable ordered NP monolayer by vacuum thermal treating a self-assembled Au NP monolayer [11,24,25]. In this process, the alkyl chains of the ligand molecule generate a deep interdigitation with each other, leading to a strong interaction between the nanoparticles and a good resistance against various solvents.…”

Gold Nanoparticle Monolayers with Tunable Optical and Electrical Properties

“…These include ligand exchange 36−42 and thermal annealing. 43,44 The former approach causes severe film cracking as a result of volume changes. 41,42,45 The latter approach can decrease the interparticle spacing but also results in a significant decrease in long-range order.…”

“…41,42,45 The latter approach can decrease the interparticle spacing but also results in a significant decrease in long-range order. 43,44 Interfacial self-assembly is powerful because of the efficiency of fabrication, the possibility for large-scale application, and the development of small interparticle gaps that are difficult to achieve with lithography. 46 In particular, the self-assembly of nanoparticles at an organic/aqueous interface has been found to achieve nanostructures over larger areas than is possible with the aforementioned techniques.…”

“…Several post-treatment approaches have been used to tune the interparticle spacing after the formation of the 2D NP superlattices. These include ligand exchange − and thermal annealing. , The former approach causes severe film cracking as a result of volume changes. ,, The latter approach can decrease the interparticle spacing but also results in a significant decrease in long-range order. , …”

Long-pulse laser launch and ionization of tailored large neutral silver nanoparticles with atomic mass assignment

“…17 Functionalization with tailored ligands can provide them with electrical, optical, catalytic, thermal or solubility properties that would be otherwise inconceivable. [18][19][20][21][22] Several techniques have been developed for volatilizing and characterizing isolated high-mass particles in high vacuum: electrospray ionization (ESI) has been used to generate highly charged beams of ligand-stabilized nanoclusters in the gas phase. [23][24][25] However, applications in soft surface deposition, 26 laser induced forward transfer, 27 classical deflectometry or fundamental tests of quantum physics 28 can profit from beams of neutral and slow nanoparticles.…”