Morphology-controlled synthesis of porous polymer nanospheres for gas absorption and bioimaging applications

This paper reports the development of a simple and effective way to prepare novel soluble porous polymer nanospheres (PPSs) by A(3)B(2) catalytic emulsion polymerization using a Suzuki reaction as a one-step, surfactant-free process. The PPSs chemical structures are characterized by Fourier transform infrared spectroscopy, transmission electron microscopy, powder X ray diffraction, dynamical light scattering, and thermogravimetric analysis. The results show that tris(4-bromophenyl) amine (A(3)) and benzene-1,4-diboronic acid (B-2) monomers in a dilute Suzuki system (1 : 20 as the ratio of toluene to water) form a A(3) core/B-2 shell nano-size micelle in the oil/water template at the early stage. With the reaction processing, the similar to 10 nm nanoparticles precipitate in droplets and move into the water phase. The small individual nanoparticles further aggregate and connect into similar to 200 nm porous nanoparticles. The controlled second level of porosity is attributed to the uniform individual nanoparticles' self-assembly. Its porosity is confirmed by N-2 sorption isotherms at 77 K. Among the PPS series, PPS3 has a high surface area of 2180m(2) g(-1) and adsorbs up to 2.08 wt% hydrogen by mass at 1.13 bar/77 K. Photoluminescence investigations have shown that PPS copolymers with different concentrations of 4,7-dibromo-2,1,3-benzothiadiazole emit blue, green and yellow light, respectively. Preliminary investigations show that PPS displays a low cytotoxicity and can be used as a fluorescence marker in bioimaging.