Photosensitization of thymine based photoresist polymers

D.M MARTINO; S. TRAKHTENBERG; J. WARNER

Andover, USA April 30 – Mayo 2

Conferencia; Green Chemistry in Practice: Applications in coatings resins & plastics conference; 2003

st1:*{behavior:url(#ieooui) } &amp;lt;!-- /* Font Definitions */ @font-face {font-family:Garamond; panose-1:2 2 4 4 3 3 1 1 8 3; mso-font-charset:0; mso-generic-font-family:roman; mso-font-pitch:variable; mso-font-signature:647 0 0 0 159 0;} /* Style Definitions */ p.MsoNormal, li.MsoNormal, div.MsoNormal {mso-style-parent:""; margin:0cm; margin-bottom:.0001pt; text-align:justify; text-indent:36.0pt; line-height:150%; mso-pagination:widow-orphan; tab-stops:36.0pt 57.6pt 108.0pt 144.0pt 208.8pt 252.0pt; font-size:11.0pt; mso-bidi-font-size:10.0pt; font-family:"Times New Roman"; mso-fareast-font-family:"Times New Roman"; mso-ansi-language:EN-US; mso-fareast-language:EN-US;} p.texto, li.texto, div.texto {mso-style-name:texto; margin:0cm; margin-bottom:.0001pt; text-align:justify; text-indent:28.8pt; line-height:17.0pt; mso-pagination:widow-orphan; font-size:12.0pt; mso-bidi-font-size:10.0pt; font-family:Garamond; mso-fareast-font-family:"Times New Roman"; mso-bidi-font-family:"Times New Roman"; mso-ansi-language:ES-TRAD; mso-fareast-language:EN-US;} @page Section1 {size:612.0pt 792.0pt; margin:70.85pt 3.0cm 70.85pt 3.0cm; mso-header-margin:36.0pt; mso-footer-margin:36.0pt; mso-paper-source:0;} div.Section1 {page:Section1;} /* List Definitions */ @list l0 {mso-list-id:2134907769; mso-list-type:simple; mso-list-template-ids:984907656;} @list l0:level1 {mso-level-text:"%1)"; mso-level-tab-stop:none; mso-level-number-position:left; mso-level-legacy:yes; mso-level-legacy-indent:-14.2pt; mso-level-legacy-space:0cm; margin-left:0cm; text-indent:0cm;} ol {margin-bottom:0cm;} ul {margin-bottom:0cm;} --&amp;gt; <!--[if !supportLists]--> <!-- /* Style Definitions */ p.MsoNormal, li.MsoNormal, div.MsoNormal {mso-style-parent:""; margin:0cm; margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:12.0pt; font-family:"Times New Roman"; mso-fareast-font-family:"Times New Roman"; mso-ansi-language:EN-US; mso-fareast-language:FR;} p.MacroAbstractText, li.MacroAbstractText, div.MacroAbstractText {mso-style-name:"Macro Abstract Text"; mso-style-next:Normal; margin-top:0cm; margin-right:0cm; margin-bottom:6.0pt; margin-left:0cm; text-align:justify; mso-pagination:widow-orphan; font-size:10.0pt; font-family:"Times New Roman"; mso-fareast-font-family:"Times New Roman"; mso-ansi-language:EN-US; mso-fareast-language:PT-BR;} @page Section1 {size:612.0pt 792.0pt; margin:70.85pt 3.0cm 70.85pt 3.0cm; mso-header-margin:36.0pt; mso-footer-margin:36.0pt; mso-paper-source:0;} div.Section1 {page:Section1;} --> In this work, the syntheses of water-soluble copolymers based on vinylbenzylthymine (VBT) and ionically charged monomers (vinylbenzyl triethylammonium chloride and vinylphenylsulfonic acid sodium salt) are investigated. The ionic groups make the polymer water-soluble, thereby eliminating the environmental and health concerns associated with the use and clean up of volatile organic solvents. The material is called a photoresist, given that after illumination with UV light a photocyclization reaction between adjacent thymines takes place, rendering it water-insoluble. The synthesis conditions determine the molecular weights distribution and chemical composition of the copolymers, influencing the solubility and the photoreactive behavior. The study focused on the effects of the monomer type, comonomer molar ratio, monomer-to-solvent ratio, reaction temperature, and reaction time, on the molecular structure, solubility, and photoreactivity properties. Samples were taken along the reactions to determine: a) monomer conversion and solubility by gravimetric analysis, and b) molecular weight distribution (MWD) by size exclusion chromatography (SEC). The curing process determines the final thermal and mechanical properties of the photoresist. The relationships between the synthesis conditions, the original molecular structure before crosslinking, the curing conditions, and the final mechanical and thermal properties are a challenging issue that is at present only beginning to be understood. The obtained VBT-based copolymers were cast onto a compatible substrate (polyethylene terephthalate), and cured by UV irradiation at room temperature. The cured material was characterized by Atomic Force Microscopy (AFM), Fourier Transform Infrared (FTIR), and UV-Vis Spectroscopy.