Adhesive Materials Utilizing a Thymine-Adenine Interaction and Thymine Photodimerization

A cross-linking reagent having two adenine units was mixed with polymers bearing thymine units to form adhesive materials utilizing both intermolecular hydrogen bonding and in situ formation of covalent bonds. In the case of 58 mol % of adenine units relative to thymine units, formation of intermolecular hydrogen bonds because of a thymine-adenine interaction was observed at room temperature using FT-IR. The peel strength became weak with heating above 60 °C, indicating breakup of intermolecular bonds between thymine and adenine units. On the other hand, UV-vis spectral measurements showed that heating at 80 °C with 254 nm light irradiation facilitated the photodimerization reaction between thymine units even in the presence of adenine cross-linking reagents. This result was consistent with a large value for the peel strength (6.5 N/10 mm) after the dual treatment, heating at 80 °C with 400 mJ/cm² of UV irradiation.