Polarized Polymer Rectangles Featuring Long-Range Ordered π-Conjugation for Anisotropic Responses to Light and Tensile Vectors.

Abstract

Micrometer-scale polarized polymeric rectangles with nanometer-scale thicknesses were fabricated through the simple reprecipitation of selected diacetylenic surfactants, exhibiting anisotropic responses to directional external fields. These 2D rectangular plates feature linearly conjugated poly(diacetylene) backbones aligned along their shorter side over large domains, enabling unique angle-dependent polarization of visible light and fluorescent emission. The conformity to Malus's law confirms the reliability of the linear polarization demonstrated by these plates. In addition to optical anisotropy, these polymer rectangles exhibit an orientation-dependent mechanical response. When tensile force is applied parallel to the shorter side or polymer backbone, the plates undergo a distinct visual color transition; however, little to no change occurs when the force is applied perpendicularly. Such an anisotropic response behavior of 2D rectangular plates is further validated by molecular dynamics simulations. This work provides a strategic framework for materials chemistry design that enables optical reflection of orientation-dependent external fields.