Interfacial change on morphological transitions in styrene–isoprene diblock copolymer

The specific interfacial area (S/V) and interfacial thickness in each microstructure of styrene–isoprene diblock copolymer were estimated by analyzing the deviations from Porod’s law. The thermally induced phase transitions proceeded from lamellae (L) to hexagonally ordered cylinder (HEX), via hexagonally perforated layer (HPL) and gyroid (G). The S/V ratio increased stepwise at the order–order transition (OOT) from L to HEX, via HPL and G. The S/V data can be utilized for OOT determination.