STRUCTURE AND SELF-ASSEMBLING EFFECTS OVER PHOTOINDUCED ANISOTROPY IN DO13-MODIFIED BLOCK COPOLYMERS

LUCIANA SAIZ; I. A. ZUCCHI; PATRICIA A. OYANGUREN; GALANTE, M.J.

Praga

Congreso; ECNP- Prague (European Centre for Nanostructured Polymers); 2012

Azopolymers have more stable thermal and mechanical properties than their respective monomers. They have been used among other applications to produce optical, artificial taste, and ph sensors. However their main characteristic is the capacity of displaying reversible cis-trans isomerization with very useful applications in optical information storage, light switching devices, surface relief gratings, holograms, and induction of liquid-crystals alignment1. To overcome the problems of the initially used guest-host systems, the active molecules have been covalently linked to the polymer backbone as either pendant group or a comonomer. Such covalently functionalized polymers can contain a large response to optical fields. Moreover, the induced anisotropy in such systems can be highly stable. Also, studies on photo-orientation processes in amorphous polymers have addressed the role of glass transition temperature (Tg) and polymer structural effects over the photo-induced anisotropy2. Recently, the development of block copolymers (BC) covalently functionalized with azobenzene units has gained importance since the confinement of photo-responsive units in nanosized block copolymer domains gives these materials unique properties. BC nanostructuration eliminated the scattering of visible light, and at the same time reduced azo aggregation3. We proposed an alternative method to obtain azo-containing diblock copolymer (DBC) that combines the advantages of a guest-host system (like easy processability) with the unique properties of block copolymers. To selectively encapsulate the chromophore within a DBC domain we utilized noncovalent interactions, such as hydrogen bonding (H-bond). The main goal of this work was to study the influence of interactions between the BC and the azo-chromophore over the optical response of the resulting materials.