Geometric structures are commonly encountered in natural and designed systems. However, the bottom-up fabrication of regular geometric assemblies with precise dimensional control, especially from soft materials, poses an outstanding challenge in contemporary materials science and chemistry. Herein, we present a general method for the preparation of colloidally stable, hexagonal platelets via the formation of crystalline inclusion complexes of tris-o-phenylenedioxycyclotriphosphazene and block copolymers bearing interactive blocks. Dictated by the screw dislocation growth of inclusion complexes, uniform hexagonal platelets with precisely controllable dimensions can be prepared. This supramolecular assembly approach is further utilized to produce concentric hexagonal platelets via stepwise seeded growth from various inclusion complexes.
A series of star azide copolymers (b-POBs) with hyperbranched polyether cores (HBPO-c) and short linear poly(3,3′-bis-azidomethyl oxetane) arms (PBAMO-a) have been prepared. The polymers were characterized with FT-IR, 1 H NMR, quantitative 13 C NMR, gel permeation chromatography, MALDI-TOF, and X-ray diffractometry. Due to hyperbranched structures, the crystallinity (W c ) of b-POBs was significantly decreased, and the processability was greatly improved. The enthalpy of formation, obtained by oxygen bomb calorimetric measurements, high azide content, and heats of decomposition of b-POBs demonstrated their remarkable energy level. Furthermore, b-POBs had good resistance to pyrolysis up to 230 °C (T 5% ), and their mechanical sensitivities were also obviously lower than that of the PBAMO homopolymer, showing their good safety properties. Moreover, the mechanism for sensitivity reduction of b-POBs was established by analyzing the relationship between the activation course in mechanical stimulus and its crystalline structure.
Aggregation-induced emission (AIE) was triggered via the spatial confinement in the coronal chains in block copolymers upon micellization, even with very low content of AIE groups attached, and this could be used to monitor the self-assembly process.
The craving for controllable assembly of geometrical nanostructures from artificial building motifs, which is routinely achieved in naturally occurring systems, has been a perpetual and outstanding challenge in the field of chemistry and materials science. In particular, the assembly of nanostructures with different geometries and controllable dimensions is crucial for their functionalities and is usually achieved with distinct assembling subunits via convoluted assembly strategies. Herein, we report that with the same building subunits of α-cyclodextrin (α-CD)/block copolymer inclusion complex (IC), geometrical nanoplatelets with hexagonal, square, and circular shapes could be produced by simply controlling the solvent conditions via one-step assembly procedure, driven by the crystallization of IC. Interestingly, these nanoplatelets with different shapes shared the same crystalline lattice and could therefore be interconverted to each other by merely tuning the solvent compositions. Moreover, the dimensions of these platelets could be decently controlled by tuning the overall concentrations.
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