Competition between polycrystalline morphology and microphase separation in blends based on cellulose triacetate

Abstract

Polymer blends based on cellulose triacetate (CTA) modified with poly(ethylene oxide-b-propylene oxide-b-ethylene oxide) triblock copolymer (PEO-PPO-PEO or EPE) and 1,1′‑diethyl-4,4′-bipyridinium dibromide (viologen or VG) were employed to obtain nanostructured micrometric films. 3VG/CTA binary blend showed worm-like structure, which was disrupted by the addition of 5 wt% of VG as a consequence of higher partial miscibility between blend components of 3VG/CTA blend. The competition between the self-assembly ability of EPE triblock copolymer and the formation of CTA crystalline lamellae was responsible for the morphology of EPE/CTA binary blends. In the ternary blends, CTA matrix was partially miscible with both VG and PEO block of EPE triblock copolymer. AFM proved that the addition of the 3 and 5 wt% of VG into had a similar effect on the final morphology of ternary systems contained 5 and 10 wt% of EPE triblock copolymer. The obtained results confirm not only self-organization ability of EPE block copolymer but also of VG. In ternary blends, VG acted as nanostructuration agent leading to similar morphology using less content of EPE block copolymer. The results provided from this investigation work allowed to build the morphologies diagram to design CTA based blends with tuneable morphologies obtained playing with VG and EPE content.