| Abstract
| - Hybrid copolymers with dendritic−linear blocks are shown to exhibit many of the classicmicrophase-separated structures of linear−linear block copolymers. Transmission electron microscopy(TEM), small-angle X-ray scattering (SAXS), and small-angle neutron scattering (SANS) were used toevaluate the morphology of a sixth generation (G6) poly(benzyl ether) dendron covalently bonded to linearpolystyrene (PS) at the dendron focal point. Increasing the fraction of the linear block, φPS, through anincrease in the molecular weight of the PS block revealed morphologies evolving from disordered to orderedlamellar to hexagonally close-packed dendron cylinders. Significantly, the observed morphologies aredistinct from those expected for analogous linear−linear blocks at equivalent volume fraction, althoughthe direction of progression follows expectation. Quantitative analysis suggests substantial moleculardeformation or shape change in the dendritic phase. The possible role of conformational entropy indetermining the overall free energy is suggested to be important for this class of block copolymer.
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