A comprehensive experimental study was carried out to replicate sub‐micron features using the injection molding technique. For the experiments, five different plastic materials were selected according to their flow properties. The materials were polycarbonate (PC), styrene‐butadiene block copolymer (SBS), impact modified poly(methyl methacrylate), methyl methacrylate‐acrylonitrile‐butadiene‐styrene polymer (MABS), and cyclic olefin copolymer (COC). Nanofeatures down to 200‐nm line width and with aspect ratios (aspect ratio = depth/width) of 1:1 could be replicated. In all selected materials, the greatest differences between the materials emerged when the aspect ratio increased to 2:1. The most favorable results were obtained with the use of high flow polycarbonate as the molding material. The best replication results were achieved when melt and mold temperatures were higher than normal values.

The aim of the present solid-state NMR study was to characterize the surface species of γ-aminopropyltriethoxysilane (APTS), γ-aminopropyltrimethoxysilane (APTMS), and γ-aminopropyldiethoxymethylsilane (APDMS) on porous silica when the deposition was performed via the gas phase. The reaction temperature used, that is, 150−300 °C, in an atomic layer deposition reactor at a pressure of 20−50 mbar, was observed to distinctly affect the surface species of aminopropylalkoxysilanes on silica. The gas−solid reactions of the precursors with the silica surface were observed to be surface-limiting at the deposition temperatures of ≤150 °C. On the basis of 29Si CP/MAS NMR, the amino ends of APTS and APTMS molecules were observed to react both with alkoxy groups of other precursor molecules and silanols of silica at deposition temperatures of ≥150 °C forming Si−N linkages. The amino groups of APDMS molecules were observed to react at 150 °C only on silica heat-treated at 200 °C in a similar way. The reaction of amino groups affected also the chemical shifts of the carbon atoms in the propyl chain causing splitting of the peaks in the 13C CP/MAS NMR spectra. At still higher reaction temperatures, especially at 300 °C, decomposition of the surface structures was observed to occur. The bonding modes of trifunctional APTS and bifunctional APDMS on silica heat-treated at 200−800 °C were systematically studied by 29Si and 13C NMR when the deposition was performed at 150 °C. Bi- and tridentate species of APTS were observed on silica pretreated at 200 °C, and mono- and bidentately bound surface structures were observed when silica was heat-treated at 450−800 °C. APTMS was also observed to attach onto silica pretreated at 600 °C in a similar way. APDMS was bound both mono- and bidentately on silica pretreated at 200 °C and at 600−800 °C but solely bidentately on silica pretreated at 450 °C.

A novel gas-phase procedure for the control of amino group density on porous silica through consecutive reactions of aminopropylalkoxysilanes and water vapor was developed. First heat-treated silica was saturated with trifunctional γ-aminopropyltrimethoxysilane (APTMS) or γ-aminopropyltriethoxysilane (APTS) in an atomic layer deposition reactor. During this step, precursor molecules were bound onto the surface both mono-and bidentately forming siloxane bridges with the silanol groups of silica. Then surface densities of 1.8 APTMS or 2.0 APTS molecules/nm 2 were achieved. Next the aminosilylated surface was treated with water vapor in order to hydroxylate the free alkoxy groups of chemisorbed aminosilane molecules. At the same time, the silanol groups on the silica surface, which had remained unreacted during the first step, were revealed below the hydrolyzed alkoxy groups. These silanol groups of silica and hydrolyzed alkoxy groups were able to react further with the next feed of aminosilane molecules. The above-mentioned aminosilane/water vapor cycles, that is, two consecutive steps, could be repeated several times, and the amino group content on silica could be controlled through the number of aminosilane/water cycles. After four cycles, the surface was observed to be saturated and maximum amino group density was achieved. Then, by performing four or five cycles, surface densities of up to 3.0 APTS or APTMS molecules/nm 2 were obtained. With this procedure, a high-density aminopropylsiloxane network is grown through horizontal polymerization of aminosilane molecules on the surface. With bifunctional γ-aminopropyldiethoxymethylsilane (APDMS), the repetition of aminosilane/water cycles did not increase the amino group content because of a lack of free and reactive ethoxy groups on the aminosilylated silica surface due to the bidentate bonding of APDMS molecules on silica.

Considerable attention is currently being devoted less to the question of whether it is possible to produce superhydrophobic polymer surfaces than to just how robust they can be made. The present study demonstrates a new route for improving the mechanical durability of water-repellent structured surfaces. The key idea is the protection of fragile fine-scale surface topographies against wear by larger scale sacrificial micropillars. A variety of surface patterns was manufactured on polypropylene using a microstructuring technique and injection molding. The surfaces subjected to mechanical pressure and abrasive wear were characterized by water contact and sliding angle measurements as well as by scanning electron microscopy and roughness analysis based on optical profilometry. The superhydrophobic polypropylene surfaces with protective structures were found to maintain their wetting properties in mechanical compression up to 20 MPa and in abrasive wear tests up to 120 kPa. For durable properties, the optimal surface density of the protective pillars was found to be about 15%. The present approach to the production of water-repellent polymer surfaces provides the advantages of mass production and mechanical robustness with practical applications of structurally functionalized surfaces.