Chemical reactions of linear trimethylsilyl-terminated poly(dimethylsiloxane)s with the surfaces of oxidized silicon, titanium, aluminum, and nickel are reported. These reactions lead to covalently attached poly(dimethylsiloxane) polymer chains and to hydrophobized inorganic surfaces. Linear silicones of this type (silicone oils) are generally not considered to be reactive with inorganic oxide surfaces, and an enormous research effort over the last 50 years to develop other silicon-containing reagents with reactive functional groups did not consider the simple alternative that we report. In retrospect, with the acknowledgment of the facile equilibration of siloxane chains with either acid or base catalysis (that was well-known in the 1940s and 1950s), the synthetic approach to functionalized inorganic surfaces by use of linear silicones is obvious. We also report the reactions of poly[3,3,3-trifluoropropyl)methylsiloxane], poly[(3-aminopropyl)methylsiloxane-co-dimethylsiloxane], poly(phenylmethylsiloxane-co-dimethylsiloxane), and poly(dimethylsiloxane-block-ethylene oxide) with oxidized silicon surfaces, which suggest that this reaction is general for silicones.

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Research concerning polyolefin synthesis is often focused on the particular catalyst being used, and the importance of the support material is generally not fully appreciated. Only a few common inorganic carriers, such as SiO2 or MgCl2, are typically described in literature, with new developments in support materials rarely found. Acknowledging this lack in fundamental research on support materials, numerous cases in which the catalyst support, particularly organic nanoparticles, plays a critical role in the formation of polyolefins are described. Here, new organic supports for both Ziegler–Natta and metallocene catalysts are described under the same conditions used for inorganic supports. In these cases, similarly high activities can be achieved, while also offering additional features based on designed polymer architectures which inorganic supports cannot provide. These features produce polyolefin fibers and core–shell structures directly from the reactor. Due to the broad synthetic variety, nanoparticles can be optimized for morphology control of the polyolefin products, such as shape and bulk density. The introduction of nucleophilic groups can further improve the binding strength between the catalyst and the support. For the design of new support systems, many of the central concepts found in nanotechnology (e.g., size control, surface properties, or nanoparticle interactions) are extremely important, and it is surprising how much modern nanotechnology has to offer such a mature field as polyolefin synthesis.

Silicon/silicon dioxide surfaces containing 3 μm (width) × 6 μm (length) × 40 μm (height) staggered rhombus posts were prepared using photolithography and hydrophobized using a perfluoroalkyl-containing monofunctional silane. These surfaces exhibit water contact angles of θ(A)/θ(R) = 169°/156°. Water drops come to rest on a carefully aligned horizontal sample but roll when the surface is tilted slightly. No visible trail or evidence of water "left behind" at the receding edge of the drop is apparent on surfaces that water drops have rolled on or on samples removed from water through the air-water interface. When dimethylbis(β-hydroxyethyl)ammonium methanesulfonate (N(+)S(-), a nonvolatile ionic liquid) is used as the liquid probe fluid (instead of water), contact angles of θ(A)/θ(R) = 164°/152° are observed and ∼3-μm-diameter sessile drops are visible (by scanning electron microscopy - SEM) on the top of every post of a sample drawn out of this liquid. We interpret the formation of these sessile microdrops as arising from microcapillary bridge failure that occurs during receding events and emphasize that the capillary bridges rupture in primarily a tensile failure mode. Smaller sessile drops could be prepared using mixtures of water and N(+)S(-). Microdroplets of N(+)S(-) were also observed to form selectively at particular features on surfaces containing square holes separated by ridges. This suggests that pinning sites can be identified using microscopy and this ionic liquid probe fluid.

Silicon wafers (silicon dioxide surfaces) were patterned by photolithograpy to contain 3 μm (width) × 6 μm (length) × 40 μm (height) staggered rhombus posts in a square array (20 μm center-to-center spacing). These surfaces were hydrophobized using a vapor phase reaction with tridecafluorooctyldimethylchlorosilane and exhibit "superhydrophobicity" (water contact angles of θ(A)/θ(R) = 169°/156°). When a section of a wafer is submerged in and withdrawn from water, the superhydrophobic surface emerges, apparently completely dry. If the same procedure is performed using aqueous sodium chloride as the liquid bath, individual crystals of the salt can be observed on the top of each of the posts. "Dip-coating crystallization" using an aqueous sodium chloride solution of 4.3 M produces crystals with ∼1 μm dimensions. A less concentrated solution, 1 M NaCl, renders crystals with ∼500 nm dimensions. These experiments suggest that superhydrophobic surfaces that emerge from water and are "apparently completely dry" are, in fact, decorated with micrometer-size (several femtoliters) sessile water drops that rapidly evaporate. This simple technique is useful for preparation of very small liquid drops or puddles (of controlled composition) and for preparation of arrays of controlled size, crystalline substances (dip-coating crystallization).