The alignment kinetics of the orientation/reorientation behavior of the microphase of a lamellarPS-b-PI diblock copolymer under large-amplitude oscillatory shear conditions is studied. By online monitoring the degree of the mechanical nonlinearity during the orientation processsas determined via the higher harmonics in Fourier transform (FT) rheologysand investigation of the orientational distribution by 2-dimensional small-angle X-ray scattering, we followed the kinetics of the microphase alignment for two different experimental shear conditions. Improved parallel alignment after increasing the shear frequency as well as spatially heterogeneous alignment via bimodal: parallel and perpendicular alignment of the lamellae is detected by both methods. Thus, FT rheology offers a new and simple way for online monitoring complex reorientation kinetics.

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