We report the self-assembly of organic-inorganic block copolymers (BCP) in thin-films by simple solvent annealing on unmodified substrates. The resulting vertically oriented lamellae and cylinders are converted to a hard silica mask by a single step highly selective oxygen plasma etching. The size of the resulting nanostructures in the case of cylinders is less than 10 nm.

Selectively plasma-etched polystyrene-block-poly(methyl methacrylate) (PS-b-PMMA) diblock copolymer masks present a promising alternative for subsequent nanoscale patterning of underlying films. Because mask roughness can be detrimental to pattern transfer, this study examines roughness formation, with a focus on the role of cross-linking, during plasma etching of PS and PMMA. Variables include ion bombardment energy, polymer molecular weight and etch gas mixture. Roughness data support a proposed model in which surface roughness is attributed to polymer aggregation associated with cross-linking induced by energetic ion bombardment. In this model, RMS roughness peaks when cross-linking rates are comparable to chain scissioning rates, and drop to negligible levels for either very low or very high rates of cross-linking. Aggregation is minimal for very low rates of cross-linking, while very high rates produce a continuous cross-linked surface layer with low roughness. Molecular weight shows a negligible effect on roughness, while the introduction of H and F atoms suppresses roughness, apparently by terminating dangling bonds. For PS etched in Ar/O 2 plasmas, roughness decreases with increasing ion energy are tentatively attributed to the formation OPEN ACCESSPolymers 2010, 2 650 of a continuous cross-linked layer, while roughness increases with ion energy for PMMA are attributed to increases in cross-linking from negligible to moderate levels.

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This article examines whether the capitalization–amortization or the direct-expensing method for insurance acquisition costs and commissions better reflects the economic substance. We find that both the currently capitalized–amortized acquisition costs and the as-if asset balance of expensed commissions are positively associated with the market value of equity, and are closely related to the level and volatility of subsequent insurance premiums. Results also show that when explaining the market value of equity, the insurance commission is significantly negative if capitalized and amortized, but is insignificant if directly expensed. The authors are the first to examine how the insurance acquisition costs and commissions are related to subsequent economic benefits, and our results are consistent with IFRS 17 under which the acquisition costs shall not be immediately expensed.