Poly(ε-caprolactone)-block-poly(ethyleneoxide) -block-poly(ε-caprolactone): Biodegradable triblock copolymer spread at the air–water interface

Synthesis, characterization and behavior at the air–water interface of A–B–A triblock copolymers are reported. The copolymers consist of a poly(ethylene oxide) central block and poly(ε-caprolactone) lateral blocks. The synthesis was controlled in order to obtain central and lateral blocks of variable length. Copolymer characterization was performed by FTIR and 1H NMR spectroscopy, size exclusion chromatography (SEC), and thermal analysis. Monolayers of the copolymers at the air–water interface were obtained by the Langmuir technique and the respective isotherms were obtained by monolayer compression. The limiting area per repeat unit (Ao) and the critical exponent of the excluded volume (ν) for spread monolayers were obtained. The static elasticity (ε0) of the monolayers was also determined. The obtained results allow proposing a schematic model of the orientation of the different blocks during the compression of the respective monolayers.