MATERIALS Synthesis of vinylbenzyl thymine (VBT) and vinylbenzyl trielthylammonium (VBA) monomers For the synthesis of VBT monomer the method of Yang et al. was used . Thymine and sodium hydroxide in a 1:1 molar ratio were dissolved in a minimum volume of distilled water and the solution was stirred at room temperature for 2 hours. Dropping the aqueous solution into ethanol the thymine sodium salt crushed out, and in order to eliminate any traces of water the thymine sodium salt was lyophilized for 24 hours. VBC (45 g – 0.296 mol), lyophilized thymine sodium salt (56.56 g – 0.325 mol), inhibitor BHT (60 mg – 0.25 mmol) and 800 mL of distilled DMF were added to a three-neck round bottom flask equipped with a condenser, a nitrogen inlet and a magnetic stirrer. The reaction was carried out at 70 °C for 24 hours under nitrogen atmosphere. The solvent was removed almost completely by rotoevaporation at 35 °C and the unreacted thymine was filtrated with boiling toluene. Filtrated solution was cooled at -5 °C, and after 24 hours the crystallized VBT was collected by filtration and dried under vacuum (yield = 47%). For the VBA synthesis, the method developed by Zarras et al. was followed . 50 mL of VBC and 200 mL of acetone were added into a round bottom flask. While the solution was stirring, 50 mL of triethylamine were added, and the reaction was run at 60 °C with reflux for 1 hour. Then, the heat was turned off and the solution was allowed to stir overnight at room temperature. The precipitated product was filtered and washed with cold acetone (yield = 99 %). Based on 1H NMR spectra (Bruker 300 MHz NMR spectrometer) and melting point results, the monomeric products were deemed pure enough for the synthesis of the polymers.