This work demonstrates the feasibility of superhydrophilic polyelectrolyte brush coatings for anti-icing applications. Five different types of ionic and nonionic polymer brush coatings of 25-100 nm thickness were formed on glass substrates using silane chemistry for surface premodification followed by polymerization via the SI-ATRP route. The cationic [2-(methacryloyloxy)ethyl]trimethylammonium chloride] and the anionic [poly(3-sulfopropyl methacrylate), poly(sodium methacrylate)] polyelectrolyte brushes were further exchanged with H+, Li+, Na+, K+, Ag+, Ca2+, La3+, C16N+, F-, Cl-, BF4-, SO4(2-), and C12SO3- ions. By consecutive measurements of the strength of ice adhesion toward ion-incorporated polymer brushes on glass it was found that Li+ ions reduce ice adhesion by 40% at -18 °C and 70% at -10 °C. Ag+ ions reduce ice adhesion by 80% at -10 °C relative to unmodified glass. In general, superhydrophilic polyelectrolyte brushes exhibit better anti-icing property at -10 °C compared to partially hydrophobic brushes such as poly(methyl methacrylate) and surfactant exchanged polyelectrolyte brushes. The data are interpreted using the concept of a quasi liquid layer (QLL) that is enhanced in the presence of highly hydrated ions at the interface. It is suggested that the ability of ions to coordinate water is directly related to the efficiency of a given anti-icing coating based on the polyelectrolyte brush concept.

Hydrophobicity, and in particular superhydrophobicity, has been extensively considered to promote ice-phobicity. Dynamic contact angle measurements above 0 °C have been widely used to evaluate the water repellency. However, it is the wetting properties of supercooled water at subzero temperatures and the derived work of adhesion that are important for applications dealing with icing. In this work we address this issue by determining the temperature-dependent dynamic contact angle of microliter-sized water droplets on a smooth hydrophobic and a superhydrophobic surface with similar surface chemistry. The data highlight how the work of adhesion of water in the temperature interval from about 25 °C to below −10 °C is affected by surface topography. A marked decrease in contact angle on the superhydrophobic surface is observed with decreasing temperature, and we attribute this to condensation below the dew point. In contrast, no significant wetting transition is observed on the smooth hydrophobic surface. The freezing temperature and the freezing delay time were determined for water droplets resting on a range of surfaces with similar chemistry but different topography, including smooth and rough surfaces in either the Wenzel or the Cassie−Baxter state as characterized by water contact angle measurements at room temperature. We find that the water freezing delay time is not significantly affected by the surface topography and discuss this finding within the classical theory of heterogeneous nucleation.

The importance of different surface geometries and thereby the need for versatile surface identification by describing a number of different surface features is emphasized. A set of topographical parameters for the description of the amplitude and spatial and hybrid properties of surfaces was utilized for a versatile three-dimensional surface characterization of sol-gel samples with different topographies. The image data were measured by atomic force microscopy. The results demonstrate the power of the roughness parameters to identify surfaces according to their specific characteristics. An example is also given about how certain surface topographical properties may control the material reactivity.

The aim of this research was to explore the use of amine-containing polymeric and low-molar-mass organic protecting agents in the preparation of copper nanoparticles. Particles were synthesized using poly(ethylene imine) (PEI) or tetraethylenepentamine (TEPA) as protecting agents. The resulting particles were studied with UV-vis spectrometry, thermogravimetry, scanning electron microscopy, and transmission electron microscopy, wide-angle X-ray scattering with heating, X-ray photoelectron spectroscopy, and Auger electron spectroscopy. The average crystal sizes for the particles were at room temperature 8.5 and 19.4 nm for PEI and TEPA, respectively, and some surface oxidation was observed. The particles were sintered on paper, and the resistance and resistivity were measured. For Cu/PEI samples, the protecting agent was removed upon sintering at relatively low temperatures (between 150 and 200 degrees C). At this temperature range, particles exhibited a rapid increase in the crystal size. Sintered particles exhibited high conductivity, indicating that these kinds of materials might find use in paper-based printing.