Pavel Solař

In this study, we performed a detailed analysis of -sputtered-nylon 6,6 plasma polymer nanoparticles (NPs). Following a previous study using standard techniques such as X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared (FTIR) spectroscopy, we employed unconventional approaches, specifically solid- and liquid-state high-resolution nuclear magnetic resonance (NMR) spectroscopy, supplemented by gel permeation chromatography (GPC). Scanning electron microscopy (SEM) was also used to examine changes in the size of the NPs after contact with solvents and after heating. Our investigations revealed suspected strong binding and networking of the NPs, and a soluble monomer/oligomer phase was identified and characterised. This fraction is removable using solvent or heat treatment without significantly affecting the size of the NPs. Additionally, we suggested the chemical structure of this soluble phase. Our findings support the proposed rubber-like character of plasma polymer NPs and explain their strong tendency to reflect from substrates upon high-speed impact.

Plasma polymer nanoparticles (pp‐NPs) are relatively easy to produce by plasma‐based gas aggregation sources. However, as experimentally evidenced in this study for the case of C:H:N:O pp‐NPs, pp‐NPs are unlike metal/metal oxide nanoparticles prone to reflection from the substrate if they hit it with too high a speed. This may result in little or no deposition rate even though the nanoparticle beam is very intense. As is shown, the deposition of pp‐NPs can be promoted either by the adjustment of their speed before they reach the substrate or by a proper selection of a substrate. Concerning the latter, enhanced capturing of pp‐NPs was observed on structured or liquid substrates.

A mechanical time-of-flight filter intended for measurement of velocities of nanoparticles exiting a gas aggregation source has been developed. Several configurations maximizing simplicity, throughput or resolution are suggested and investigated both theoretically and experimentally. It is shown that the data measured using such filters may be easily converted to the real velocity distribution with high precision. Furthermore, it is shown that properly designed filters allow for the monitoring of the velocity of nanoparticles even at the conditions with extremely low intensity of the nanoparticle beam.

Metal‐polymer nanocomposites have gained increasing attention due to the wide potential applications field. Synthesis of nanoparticles from the gas phase is an intensively studied alternative to the chemical preparation methods. We present a one‐step procedure that combines magnetron‐based gas aggregation cluster source of silver nanoparticles and simultaneous plasma‐enhanced chemical vapour deposition of hexamethyldisiloxane (HMDSO). The key parameter of the process, significantly influencing the morphology and microstructure of studied nanoparticles, was found to be the amount of HMDSO added to the deposition chamber as witnessed by small angle X‐ray scattering and X‐ray diffraction methods combined with transmission electron microscopy and UV–Vis spectrophotometry. The presence of HMDSO in the chamber leads to changes in the size distribution and also in the architecture of prepared nanoparticles. The increasing amount of HMDSO induces the formation of individual core‐shell nanoparticles, chains of core‐shell nanoparticles, and for the highest concentration of HMDSO, the synthesis of multi‐core‐shell nanoparticles. The size of crystallites in the silver cores of nanoparticles decreases with addition of HMDSO, which prevents further aggregation.

A modified version of Haberland type gas aggregation source with an arrow-shaped aggregation chamber set with two magnetrons was used for the production of core@shell Ni@Ti nanoparticles. This configuration that had two separate magnetrons in one aggregation chamber gave the possibility to independently control the power to each magnetron and thus to control the structure of created nanoparticles. Furthermore, the chosen geometry resulted, under optimized conditions, in the suppression of the formation of single-material nanoparticles that is a common problem in the case of conventionally used planar arrangement of magnetrons in the aggregation chamber.

Kinetic aspects of the synthesis of Ag nanoparticles (NPs) by magnetron sputtering are studied by in situ and time‐resolved small angle X‐ray scattering (SAXS). Part of the NPs are found to become confined within a capture zone at 1–10 mm from the surface of the target and circumscribed by the plasma ring. Three regimes of the NP growth are identified: 1) early growth at which the average NP diameter rapidly increases to 90 nm; 2) cycling instabilities at which the SAXS signal periodically fluctuates either due to expelling of large NPs from the capture zone or due to the axial rotation of the NP cloud; and 3) steady‐state synthesis at which stable synthesis of the NPs is achieved. The NP confinement within the capture zone is driven by the balance of forces, the electrostatic force being dominant. On reaching the critical size, large NPs acquire an excessive charge and become expelled from the capture zone via the electrostatic interactions. As a result, significant NP deposits are formed on the inner walls of the aggregation chamber as well as in the central area of the target.