Journal of Photochemistry and Photobiology A: Chemistry 138 (2001) 23–27 Corona inhibition by photochemical dissolution of Al films by polymeric composition Vladislav A. Kolesnikov ∗ , Marine G. Tedoradze, Alexander A. Nekrasov, Antonina D. Grishina, Anatoly V. Vannikov A.N. Frumkin Institute of Electrochemistry, Russian Academy of Sciences, Leninskii Prospect 31, Moscow 117071, Russia Received 27 June 2000; accepted 12 September 2000 Abstract Conductivity dependence on time for the ’exposed to ultra-violet light’ polymeric composition of poly(N-epoxypropylcarbazole) (PEPC) with CBr 4 on Al film substrate was measured. Photochemical reaction takes place under ultra-violet irradiation, which leads to dissolving of vacuum deposited Al film and organometallic complexes formation in polymer bulk. Inhibition of Al dissolving by positive corona charge of outer polymer surface was found. © 2001 Elsevier Science B.V. All rights reserved. Keywords: Dark discharge; Photochemical reactions; Metal etching; Organometallic complex; Conducting polymers 1. Introduction In our previous papers, we considered dry etching of metallic (Bi, Al, Cu and Ni) films [1–3] by intermedi- ate and final photolysis products formed in polymeric layers deposited onto these films. It was established that photochemical etching of metallic films is due to its dis- solving in exposed polymeric layers [4]. In the practical aspect, photochemical doping of polymers with organometal- lic compounds can be used to prepare the layers containing conducting latent image that can be visualized by toner and multiply reproduced by electrographic master. In the present work it is established that corona charging during dark conductivity measurements by electrographic technique can lead to inhibition of metal film dissolution in polymeric layers. A weak charge transfer complex (PEPC·CBr 4 ) between the carbazolyl group of PEPC as the donors and CBr 4 as the acceptor is formed at introduction of the elec- trophilic additive CBr 4 to poly(N-epoxypropylcarbazole) ∗ Corresponding author. Fax: +7-095-9520846. E-mail address: vanlab@online.ru (V.A. Kolesnikov). (PEPC). The complex has a maximum in absorption spec- trum in UV-region at λ = 405 nm [5,6]. Photoexcita- tion of the complex results in the formation of a radical PEPC • , acid HBr, bromoform CHBr 3 , etc. [5] by reactions, which, following analogy with the reaction of CBr 4 with poly(N-vinylcarbazole) described in the paper by Smets et al. [6], may be written as PEPC · CBr 4 + hν → PEPC •+ + CBr 3 • ··· Br − (1) PEPC •+ + CBr 3 • ··· Br − → 3-CBr 2 ==PEPC + Br − + HBr (2) 3-CBr 2 ==PEPC + Br − + PEPC → CP + HBr (3) PEPC •+ + CBr 3 • ··· Br − → α-CBr 3 –PEPC + HBr (4) PEPC •+ + CBr 4 → 3-Br–PEPC + H + + CBr 3 • (5) CBr 3 • + PEPC → PEPC • + CHBr 3 (6) (–CH 2 –C(Cz)H–O–CH 2 –) + HBr → (–CH 2 –C(Cz)H–OH + CH 2 Br − ) (7) 1010-6030/01/$ – see front matter © 2001 Elsevier Science B.V. All rights reserved. PII:S1010-6030(00)00379-8