Observation of fine structure in bicontinuous phase-separated domains of apolymer blend by laser scanning confocal microscopy

Laser scanning confocal micrographs for blends of poly(styrene-ran-butadien e) (SBR) and polybutadiene (PB) demonstrated the existence of fine structur es inside one of the well-characterized macroscopically phase-separated bic ontinuous domains, in the depth range of the blends belonging to the bulk. The average size of the fine structures was on the submicrometer length sca le, while the characteristic spacing of the macroscopically phase-separated domains was on the order of 10 mum. Fluorescence laser scanning confocal m icrographs revealed that the fine structures exist only in the SBR-rich pha se. Although the driving force for the formation of the fine structures nee ds to be investigated further, a small amount of PB molecules in the SBR-ri ch domains seems to play an important role. Illumination and highlights wer e shed on the advantage of using laser scanning confocal microscopy for inv estigation of fine structures in the polymer blends.