Light-triggered surface properties of a glycolized PolyEthylene Terephthalate film by surface-initiated ATRP of azobenzene monomer

The surface modification of glycolyzed polyethylene terephthalate (PETg) was performed by surface-initiated ATRP with a statistical copolymer composed of poly(butyl acrylate) (PBuA) and poly(styrenic azobenzene) (PSA). First, a bromo end-capped PETg was previously synthesized and then used to obtain thick films by melting under pressure. The top surface Bromo moieties of the PETg were activated as ATRP macro-intiator to polymerize Butyl Acrylate (BuA) and styrenic azobenzene (SA) monomer. In the meantime, a serial of statistical copolymers was synthetized based on SA and BuA units to finely tuned the glass transition temperature value of copolymer close to the room temperature. The introduction of the BuA unit decreased the initial Tg value of the PSA from 100 to -10 degrees C. A statistical copolymer P(BuA-stat-SA) with 40 wt% of BuA units with a Tg value around 20 degrees C was then initiated from the surface of the PETg film to be chemically anchored. Under illumination at 365 nm and 450 nm, a reversible Trans to Cis isomerization of the P(BuA-stat-SA) layer is observed which induces a strong shift of the transmittance of the PET film as a light-triggered UV-protection and wettability. Such materials can be used in the field of flexible substrates for electronic to create light-triggered surfaces properties to tune their adhesion and wettability.

Automated summary

The surface modification of glycolyzed polyethylene terephthalate (PETg) was achieved through surface-initiated ATRP method, resulting in the synthesis of copolymer P(BuA-stat-SA). By adjusting the glass transition temperature of the copolymer, light-triggered UV protection and wettability were successfully achieved. These materials can be used in the field of flexible electronic substrates to enhance adhesion and wetting properties through surface property tuning.