The self-assembly of liquid crystals and block copolymers into ordered structures often defines the functional properties of these materials. In discrete end-functionalized oligomers, phase-segregation is combined with the directional interactions well-known in liquid crystalline materials. An end-functionalized discrete siloxane oligomer induces phase-segregation and the peripheral block can have a supramolecular hydrogen bonding character or exhibits crystalline interactions. In this study, discrete siloxane oligomers are decorated with dinitrohydrazone end blocks that show both supramolecular and crystalline interactions. An extensive morphological study elucidates the formation of highly ordered and aligned cylinders, irrespective of the volume fractions of the blocks. The ordered structure can be switched to an isotropic structure within 1 degree Celsius, in less than 15 seconds. The isotropic to ordered transition occurs within the same time span and at nearly the same temperature resulting in a material that is very sensitive for temperature and possesses a fast thermal switch. Finally, a disperse reference compound confirms that the discreteness of the siloxane linker is crucial to obtain these unexpected, highly ordered morphologies and macroscopic properties.

Unexpected morphologies in discrete end-functionalized oligomers

2019 Spring National Meeting

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