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  • 1
    Electronic Resource
    Electronic Resource
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 35 (1997), S. 77-89 
    ISSN: 0887-624X
    Keywords: poly(phthalaldehyde) ; degradation mechanism ; molecular orbital theory ; activation energy of degradation ; acid catalyzed degradation ; unzipping reaction ; resist ; chemical amplification ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The acid-catalyzed degradation mechanism of chemical amplification resists based on end-capped poly(phthalaldehyde) has been elucidated by semi-empirical molecular orbital calculations. It is concluded that: (i) two different starting points exist in the degradation of end-capped poly(phthalaldehyde), the central part of the polymer as well as the polymer end; (ii) in both cases, after the first protonation, cationic hydroxyl compounds generated decompose to the identical cation intermediate, which can unzip itself to phthalaldehyde monomers successively (unzipping reaction); (iii) the hemiacetal type intermediates hardly degrade to the same intermediate without acid catalyst; (iv) the overall activation energy for the degradation reaction is less than 14 kcal/mol in all the cases. Thus, the poly(phthalaldehyde) resist can easily self-develop below 100°C, as reported in the literature. © 1997 John Wiley & Sons, Inc.
    Additional Material: 16 Ill.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Chemistry Edition 17 (1979), S. 3759-3773 
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The Millar-Wall-Charlesby empirical rule of radiation effects on polymers was theoretically examined. The theoretically calculated adiabatic potential curves of the main chain scission and side chain cleavage revealed that the effects of radiation on polymers are clearly interpreted as chemical reactions in the excited states; namely, that degradation occurs when little or no activation energy is required in the main chain cleavage reaction in the excited states, or, in other words, stabilization of the excited polymer molecule leads to the main chain cleavage. Crosslinking occurs when moderate or large activation energy is required in the main chain cleavage reaction in any electronic state and little or no activation energy is needed in the C—H bond cleavage reaction in the excited states. Therefore stabilization of the excited polymer molecule leads to the formation of a polymer radical that crosslinks. It was concluded that Millar-Wall-Charlesby's rule is exact only when the shape of the adiabatic potential curve in the ground state reflects those in the excited states.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
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