Mass and density determination of porous nanoparticle films using a quartz crystal microbalance

Abstract

A method is presented to directly measure the mass output of an impaction printer coupled with a spark ablation generator. It is based on a quartz crystal microbalance and shown to be reliable in quantifying mass deposition rate. Here, the method is demonstrated with an Au nanoparticle aerosol synthesized under several spark ablation and deposition settings. Changes in the deposition rate in response to changed synthesis conditions follow the spark ablation models on generation rate made in previous studies, validating this novel measurement method. In combination with the volume of a deposit, a good estimate of the film porosity can be made. The Au nanoparticle films synthesized here have a low porosity of 0.18 due to extensive restructuring and compaction on impact with the substrate. The porosity is found to be insensitive to deposition settings and is constant throughout the film. The simplicity and low cost of a quartz crystal microbalance setup make this an accessible method to determine porosity in porous thin films.

Nanostructured Thermoelectric Films Synthesised by Spark Ablation and Their Oxidation Behaviour

“…The mass deposition process can be seen in Figure 8A and showed a similar characteristic apparent mass deposition rate as the one described in Van Ginkel et al [35]. This was due to the decreasing mass sensitivity near the edges of the electrode, resulting in a lower response of the QCM for the same deposition rate.…”

“…The porosity was determined using a method developed by our group [35]. It is an indirect method to determine the porosity of a material by creating identical deposits and extracting their density from different measurements.…”

Quantitative MALDI-MS and Imaging of Fungicide Pyrimethanil in Strawberries with 2-Nitrophloroglucinol as an Effective Matrix

“…Equation applies under conditions that (i) the mass deposition is uniform over the entire piezoelectrically active area, (ii) the film is rigid and resonates with the crystal, and (iii) the frequency change is within 2% of the base frequency . The active area of the QCM crystal follows a Gaussian distribution in the radial direction (∼4 mm radius) from the center of the crystal .…”

Fabrication of Nanoparticle Agglomerate Films by Spark Ablation and Their Application in Surface-Enhanced Raman Spectroscopy

“…There are many ways to produce and deposit NPs, among which we will focus on the so-called aerosol techniques, which result in the formation of particles dispersed in a gaseous medium [8,9]. Aerosol-based NP generation methods can be combined with direct deposition methods, such as collection on filters [10], impaction printing [11,12], thermophoretic- [3,13], or electric field-guided deposition [14,15], hence providing powerful tools to fabricate nanoparticle films for various applications.…”

“…These applications used different approaches to deposit the NPs to a surface, starting from the most straightforward filtering [10] to a highly sophisticated, electrical field-assisted 3D microprinting method [49]. Among all the different approaches, the impaction-based deposition has already been shown to be sufficiently simple to integrate into an industrial-level NP printer [11,45] and versatile enough to be applicable on various substrates, including optical fibers [50] or polymers [51].…”