Imaging of Aliphatic Polycarbonates with Photogenerated Base
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- 作者：Jack D. Davies and ; William H. Daly ; Zhikai Wang ; and Charles Kutal
- 刊名：Chemistry of Materials
- 出版年：1996
- 出版时间：April 1996
- 年：1996
- 卷：8
- 期：4
- 页码：850 - 855
- 全文大小：236K
- 年卷期：v.8,no.4(April 1996)
- ISSN：1520-5002
文摘
A series of aliphatic polycarbonates based on the condensationcopolymerization of thebischloroformate of 2,2,4,4-tetramethyl-1,3-cyclobutanediol (TMCBD)with itself and the diolsof 3-cyclohexene-1,1-dimethanol, 1,4-cyclohexanediol (CHD), in variousmolar ratios, exo,exo-tricyclo[2.2.1.02,6]heptane-3,5-diol, and4,8-bis(hydroxymethyl)tricyclo[5.2.102,6]decane(BTD)were synthesized. Incorporation of cyclic and tricyclic repeatunits produced polycarbonateswith high glass transition temperatures (Tg's),high molecular weights, and low refractiveindexes. The crystallinity of the TMCBD homopolymer was minimizedin the CHD/TMCBDcopolymers with little effect on Tg but withdecreased thermal stability. Thermal analysisyields decomposition temperatures ranging from 354 
C for the TMCBDhomopolymer to292-298 C for the CHD/TMCBD copolymers; all polymers undergocomplete thermaldegradation. Refractive indexes range from 1.493 for the 1:1copolymer of BTD and TMCBDto 1.481 for the CHD/TMCBD copolymers. Thin films composed of analiphatic polycarbonateand a base-releasing cobalt(III) photoinitiator can be imaged withdeep-UV light. Thepolycarbonates selected for study were the 9:1 copolymer of CHD andTMCBD and the 1:1copolymer of BTD and TMCBD. The first step of image formation isthe efficient photoredoxdecomposition of the photoinitiator with the release ofmultiequivalents of Lewis base. Inthe case of[Co(en)3](BPh4)3 (en isethylenediamine, BPh4- is tetraphenylborate),photogenerated ethylenediamine cross-links the polymer chains via formation ofbis(dicarbamate)linkages. Development with solvent dissolves the unirradiatedareas to yield negative-toneimages. For[Co(NH3)6](BPh4)3,photoreleased ammonia causes chain scission in the exposedregions of the film, and wet or dry development results inpositive-tone images.
C for the TMCBDhomopolymer to292-298 C for the CHD/TMCBD copolymers; all polymers undergocomplete thermaldegradation. Refractive indexes range from 1.493 for the 1:1copolymer of BTD and TMCBDto 1.481 for the CHD/TMCBD copolymers. Thin films composed of analiphatic polycarbonateand a base-releasing cobalt(III) photoinitiator can be imaged withdeep-UV light. Thepolycarbonates selected for study were the 9:1 copolymer of CHD andTMCBD and the 1:1copolymer of BTD and TMCBD. The first step of image formation isthe efficient photoredoxdecomposition of the photoinitiator with the release ofmultiequivalents of Lewis base. Inthe case of[Co(en)3](BPh4)3 (en isethylenediamine, BPh4- is tetraphenylborate),photogenerated ethylenediamine cross-links the polymer chains via formation ofbis(dicarbamate)linkages. Development with solvent dissolves the unirradiatedareas to yield negative-toneimages. For[Co(NH3)6](BPh4)3,photoreleased ammonia causes chain scission in the exposedregions of the film, and wet or dry development results inpositive-tone images.