Theoretical and Experimental Study of Thymine Based Photoresists Polymers

F. GARCÍA; C. LUCIANI; D. MARTINO; D. REYNA; D. ESTENOZ; G. MEIRA; J. WARNER

Foz do Iguazu, Brazil

Congreso; CBECIMAT, 17° Congresso Brasileiro de Engenharia e Ciência dos Materiais; 2006

Styrene-based biopolymers containing ionic and thymine groupschemically attached to the polystyrene structure were experimental- and theoreticallyinvestigated. The ionic groups make the polymer water-soluble, eliminating theenvironmental and health concerns associated with the use of volatile organic solventsas in conventional photoresist processes. The material is called a photoresist, given thatafter illumination with UV light a photocyclization reaction between adjacent thyminestakes place, rendering it water-insoluble. The experimental work involved a series ofcopolymerizations of vinylbenzyl thymine and vinylbenzyl triethylammonium chloride orvinylphenylsulfonic acid sodium salt. Samples were taken along the reactions todetermine monomer conversion, solubility, and molecular weight distribution. Theobtained copolymers were cured by UV irradiation at room temperature. The curedmaterial was characterized by AFM, FTIR, and UV-Vis Spectroscopy. A mathematicalmodel that simulates the synthesis of the biocompatible prepolymer was developed.Theoretical predictions are in good agreement with measurements. Also, an incipientmodel for the curing process was presented.