Dynamic light scattering is a method that depends on the interaction of light with particles. This method can be used for measurements of narrow particle size distributions especially in the range of 2–500 nm. Sample polydispersity can distort the results, and we could not see the real populations of particles because big particles presented in the sample can screen smaller ones. Although the theory and mathematical basics of DLS technique are already well known, little has been done to determine its limits experimentally. The size and size distribution of artificially prepared polydisperse silver nanoparticles (NPs) colloids were studied using dynamic light scattering (DLS) and ultraviolet‐visible (UV‐Vis) spectroscopy. Polydisperse colloids were prepared based on the mixture of chemically synthesized monodisperse colloids well characterized by atomic force microscopy (AFM), transmission electron microscopy (TEM), DLS, and UV‐Vis spectroscopy. Analysis of the DLS results obtained for polydisperse colloids reveals that several percent of the volume content of bigger NPs could screen completely the presence of smaller ones. The presented results could be extremely important from nanoparticles metrology point of view and should help to understand experimental data especially for the one who works with DLS and/or UV‐Vis only.

Substrates of aluminum (Al) deposited by physical vapor deposition onto Si substrates and then chemically reacted with perfluorodecylphosphonic acid $(\mathrm{PFDP}∕\mathrm{Al}∕\mathrm{Si})$ , decylphosphonic acid ($\mathrm{DP}∕\mathrm{Al}∕\mathrm{Si})$ , and octadecylphosphonic acid $(\mathrm{ODP}∕\mathrm{Al}∕\mathrm{Si})$ were studied by x-ray photoelectron spectroscopy (XPS), contact angle measurements, atomic force microscopy (AFM), and friction force microscopy, a derivative of AFM, to characterize their surface chemical composition, roughness, and micro-/nanotribological properties. XPS analysis confirmed the presence of perfluorinated and nonperfluorinated alkylphosphonate molecules on the $\mathrm{PFDP}∕\mathrm{Al}∕\mathrm{Si}$ , $\mathrm{DP}∕\mathrm{Al}∕\mathrm{Si}$ , and $\mathrm{ODP}∕\mathrm{Al}∕\mathrm{Si}$ . The sessile drop static contact angle of pure water on $\mathrm{PFDP}∕\mathrm{Al}∕\mathrm{Si}$ was typically more than 130° and on $\mathrm{DP}∕\mathrm{Al}∕\mathrm{Si}$ and $\mathrm{ODP}∕\mathrm{Al}∕\mathrm{Si}$ typically more than 125° indicating that all phosphonic acid reacted $\mathrm{Al}∕\mathrm{Si}$ samples were very hydrophobic. The surface roughness for $\mathrm{PFDP}∕\mathrm{Al}∕\mathrm{Si}$ , $\mathrm{DP}∕\mathrm{Al}∕\mathrm{Si}$ , $\mathrm{ODP}∕\mathrm{Al}∕\mathrm{Si}$ , and bare $\mathrm{Al}∕\mathrm{Si}$ was approximately $35\mathrm{nm}$ as determined by AFM. The surface energy for $\mathrm{PFDP}∕\mathrm{Al}∕\mathrm{Si}$ was determined to be approximately $11\mathrm{mN}∕\mathrm{m}$ by the Zisman plot method compared to 21 and $20\mathrm{mN}∕\mathrm{m}$ for $\mathrm{DP}∕\mathrm{Al}∕\mathrm{Si}$ and $\mathrm{ODP}∕\mathrm{Al}∕\mathrm{Si}$ , respectively. Tribology involves the measure of lateral forces due to friction and adhesion between two surfaces. Friction, adhesion, and wear play important roles in the performance of micro-/nanoelectromechanical systems. $\mathrm{PFDP}∕\mathrm{Al}∕\mathrm{Si}$ gave the lowest adhesion and coefficient of friction values while bare $\mathrm{Al}∕\mathrm{Si}$ gave the highest. The adhesion and coefficient of friction values for $\mathrm{DP}∕\mathrm{Al}∕\mathrm{Si}$ and $\mathrm{ODP}∕\mathrm{Al}∕\mathrm{Si}$ were comparable.