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Solid films of C6o and C7o fullerenes are evaluated in propylene carbonate/lithium perchlorate, an electrolyte commonly used in lithium batteries. Cyclic voltammetry, chronopotentiometry, and an effusion test, show that reduced C6o and C70 are soluble in the electrolyte tested, which, coupled with poor stability of the highly reduced material and poor electrochemical reversibility, would compromise the performance of secondary batteries based on these fullerenes.

Alicyclic polymers, such as substituted polynorbornene (PNB), are expected to be one potential material solution for providing transparent photoresist polymer resins for photolithography at 193 and 157 nm wavelengths. In this work, the dissolution behavior of bis(trifluoromethyl)carbinolsubstituted polynorbornene (HFAPNB) in aqueous alkaline solutions as a function of polymer molecular weight is explored. Surprisingly, it was found that the dissolution rate of bis(trifluoromethyl)carbinolsubstituted polynorbornene increased with increasing molecular weight over the range from approximately 10,000 to 100,000 Mw. Experimental results show that this polymer displays strong hydrogen bonding in the solid film form and that such hydrogen bonding is disrupted as the polymer molecular weight is increased. On the basis of this evidence, an explanation for this unusual dissolution behavior based upon disruption of hydrogen bonding is presented.

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Summary: Homopolymers of a bis‐trifluorocarbinol substituted norbornene (1) (α,α‐bis(trifluoromethyl)bicyclo[2.2.1]hept‐5‐ene‐2‐ethanol or HFANB) and copolymers of 1 with t‐butyl ester of 5‐carboxylic acid (2, t‐BuEsNB) were produced using palladium catalysts and olefinic chain transfer agents such as 1‐hexene and ethylene to control molecular weight. However, these low‐molecular‐weight polymers exhibited relatively low optical transparencies at 193 nm. In fact, the opacity (measured as optical densities in absorbance units per micron) of thin films of these homo‐ and co‐polymers was inversely proportional to their molecular weight. This relationship is consistent with an end group contribution to the film opacity. Spectroscopic analysis of these polymers by 1H NMR and MALDI‐TOF MS confirmed that 1‐hexene and ethylene chain transfer agents generated olefin‐terminated vinyl addition polymers. The olefinic end group contribution to optical density can be eliminated by appropriate chemical modification. Both epoxidation and hydrogenation of the polymer olefinic end groups generated very low optical density materials, independent of molecular weight, that are suitable as 193‐nm photoresist binder resins.End group modification of vinyl and hexenyl‐terminated homopolymers of 1 by epoxidation or hydrogenation.magnified imageEnd group modification of vinyl and hexenyl‐terminated homopolymers of 1 by epoxidation or hydrogenation.