Three-dimensional ceramic nanostructured films were produced from silicon-containing triblock copolymer films exhibiting the double gyroid and inverse double gyroid morphologies (space group Ia3d). A one-step room-temperature oxidation process that used ozonolysis and ultraviolet irradiation effected both the selective removal of the hydrocarbon block and the conversion of the silicon-containing block to a silicon oxycarbide ceramic stable to 400 degrees C. Depending on the relative volume fraction of the hydrocarbon block to the silicon- containing block, either nanoporous or nanorelief structures were fabricated with calculated interfacial areas of approximately 40 square meters per gram and pore or strut sizes of approximately 20 nanometers.

In response to thermodynamic driving forces, the domains in microphase-separated block copolymers have distinct intermaterial dividing surfaces (IMDS). Of particular interest are bicontinuous and tricontinuous, triply periodic morphologies and their mathematical representations. Level surfaces are represented by functions F:where t is a constant. Level surfaces make attractive approximations of certain recently computed triply periodic constant mean curvature (cmc) surfaces and they are good starting surfaces to obtain cmc surfaces by mean curvature flow. The functions F(x, y, z) arise from the nonzero structure factors F(hkl) of a particular space group, such that the resulting surfaces are triply periodic and maintain the given symmetries. This approach applies to any space group and can, therefore, yield desired candidate morphologies for novel material structures defined by the IMDS. We present a technique for generating such level surfaces,give new examples, and discuss certain bicontinuous cubic IMDS in detail.

No abstract

Thousand cankers disease of black walnut is caused by aggressive feeding by the walnut twig beetle and subsequent canker development around beetle galleries caused the fungus Geosmithia morbida. The authors We confirmed the presence of G. morbida from symptomatic black walnut or hybrids in California, Colorado, Idaho, New Mexico, Oregon, Utah, and Washington. Thousand cankers disease continues to cause extensive mortality to black walnut over a wide geographic region and is intensifying in the western United States. Accepted for publication 2 June 2011. Published 30 June 2011.