Synthesis And Self-assembly Of Coil-rod-Coil Molecules With Lateral Groups In The Center Of The Rod Segment

Self-assembly of rod-coil molecules are widely studied due to their remarkable potentials as a advanced functional materials. Rod-coil molecules, consisting of a flexible and a rigid block, have a strong capacity to self-assemble into a variety of ordered nanostructures in the bulk state. In this paper, synthesis and characterization of the self-assembly behavior of coil-rod-coil oligomers. These new materials consist of five biphenyls linked together with ether bonds as a rod segment and poly(ethylene oxide) (PEO) with a degree of polymerization (DP) of 7,12 and 17 coil segments and incorporate lateral methyl or ethyl groups in the center of the rod building block. Consider the lateral chain length of rod center impact of the self-assembly.Structural investigation of these molecules by means of differential scanning calorimetry (DSC) and X-ray scattering (XRD) in the bulk state reveals that lateral chains, In the solid state, all of the molecules self-assemble into layered structure; In the liquid-crystalline phase, Molecules containing a lateral methyl group based on PEO coil chain (DP 7) self-organize into a layer (L) structure, and degree of polymerization of 12 and 17 molecular self-assembly into a hexagonally perforated layer (HPL) structure, while the molecule with a lateral ethyl group based on PEO coil chain (DP of 7) self-assembles into a 2-D rectangular columnar, and degree of polymerization of 12 and 17 molecular have no liquid crystal phase. Therefore, with the end of the flexible chain length increases, the liquid crystal phase of coil-rod-coil oligomers is reduce, and self-assembly tends to disorder. When the flexible chain length the same, with the center of rod lateral groups length increases, the coil-rod-coil oligomers easy to self-assemble into a larger surface area of the phase structure. Results, with the center of rod lateral groups length and the end of the flexible chain length increases, both the molecular self-assembly tends to disorder.In addition, synthesis the coil-rod-coil molecules, consist of five benzenes linked together with triple bonds as a rod segment and poly(ethylene oxide) (PEO) with a degree of polymerization (DP) of 7 and 12 coil segments. and incorporating lateral ethyoxyl groups in the center of the rod building block. Results, the molecules based on PEO coil chain (DP of 7) self-organize into a lamellar structure in the crystal, while the molecule based on PEO coil chain (DP of 12) is liquid phase in the room temperat, All of the molecules in water self-assemble into spherical aggregates.