MEH‐PPV/SBS composite films: Localization and luminescence properties of conductive polymers with microphase separation

Abstract This study reports the synthesis of a flexible light‐emitting polymer film by casting the solution formed by blending poly[2‐methoxy‐5‐((2‐ethylhexyl)oxy)‐1,4‐phenylenevinylene] (MEH‐PPV) with poly(styrene‐co‐butadiene‐co‐styrene) (SBS). Scanning force microscopy (SFM) and differential scanning calorimetry (DSC) confirm that MEH‐PPV molecules are selectively positioned in the polystyrene (PS) domain of the fabricated film. As MEH‐PPV molecules are dissolved in the PS phase without aggregation, the photoluminescence (PL) spectrum of the MEH‐PPV/SBS film exhibits a nanometer‐scale bicontinuous luminescent domain with low aggregation quenching. Furthermore, the MEH‐PPV/SBS film exhibits typical elastomeric characteristics (with linear elasticity, a plateau, and densification regions in its stress–strain curves), and its tensile properties are comparable to those of neat SBS films. As MEH‐PPV molecules are almost absent in the polybutadiene (PB) phase (which influences the bulk‐film elastic properties), the concentration of MEH‐PPV shows very little effect on the elastic properties of the composite film.