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Synthesis and radiation grafting modification of hydroxyl controlled AM/HEMA polymer microspheres
摘要： The, smooth-faced, highly cross-linked, hydroxyl controlled, micrometer-sized polymer micro-spheres of acrylamide (AM) and 2-hydroxyethyl methacrylate (HEMA) were prepared by reverse suspension polymerization. The polymerization parameters showed considerable influence on the morphologies and dispersion of the polymer particles, such as the stirring rate, polymerization temperature, monomer loading, initiator concentration, and crosslinking agent concentration, which makes it flexible to control the hydroxyl number of AM/HEMA microspheres by controlling polymerization conditions. Subsequently, the polymer particles was radiated with 60Co c-rays(dose rate: 4.0 kGy/h) in pure oxygen environment for 24 h, as a result, free radicals are generated on the surface of the polymer microspheres. Afterward, AM was allowed to be graft-polymerized on microspheres AM/HEMA in the manner of “grafting onto,” resulting in the grafted microspheres PAM–AM/HEMA. This work provides optimized parameters to fabricate micron-sized AM/HEMA microspheres, and further expands the functionalization of AM/HEMA microspheres and its application fields.
关键词： polymer microspheres,graft-modification,hydroxyl controlled,Synthesis
更新于2025-09-23 15:19:57
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Self-assembly of colloidal Poly(St-MMA-AA) core/shell photonic crystals with tunable structural colors of the full visible spectrum
摘要： This study used the copolymer emulsion method to synthesize colloidal monodisperse core/shell microspheres composed of the poly(styrene-co-methyl methacrylate-co-acrylic acid) [Poly(St-MMA-AA)]. Colloidal photonic crystal (CPhC) films have prepared by using polymer composite microspheres and successfully fabricated via natural sedimentation. The synthesized results of polymer composite microsphere exhibited uniform and good morphology. The resultant of CPhC color films demonstrated vividly structural colors due to 3D CPhC nanostructures. The structural colors over full visible spectra could be tuned by controlling the filling factor of crystals and diameter of microspheres according to the Bragg law. Additionally, the structural color of Poly(St-MMA-AA) CPhC films has measured under the standard colorimetric system. This study demonstrated a approach to fabricate tunable structural color for numerous applications.
关键词： Photonic crystals,Polymer microspheres,Structural colors,Colloidal crystals,Self-assembly
更新于2025-09-10 09:29:36
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Selective Recognition of Fe(III) in Aqueous Environment over Covalently-Bonded Tb-Complex-Containing Fluorescent Porous Copolymer Microspheres
摘要： An environment-friendly synthesis of a covalently bonded terbium(Tb)-complex-containing monodispersed fluorescent porous copolymer microspheres, and their highly selective detection of Fe3+ are described. The as-made copolymer microspheres exhibit intense green fluorescence originating from Tb ions and high photostability in water. Encouragingly, the fluorescence of the copolymer microspheres can be selectively quenched by trace Fe3+ due to the interaction between Fe3+ and the ligands, which disturbs the coordination structure of Tb-complexes and inhibits the energy transfer from ligands to Tb ions. The intense fluorescence intensity, high fluorescence stability, together with the nanoscale and porous nature of the copolymer microsphere endows them with wide detection range (0–1500 μm) and low detection limit (2.1 μm) for selective recognition of Fe3+ in aqueous environment. This study paves a new pathway for the function of porous copolymer microspheres being used as targeting for biological detection and environmental issues.
关键词： Tb-complex,fluorescence sensors,iron ions,luminescence,polymer microspheres
更新于2025-09-10 09:29:36
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High Optical Energy Storage and Two-Photon Luminescence from Solution-Processed Perovskite-Polystyrene Composite Microresonators
摘要： Optical green emitting microresonators with high values of nonlinearity are desired for high optical up-conversion energy storage and lasing applications. Here we report on the synthesis of benzylammonium lead iodide (BALI) perovskite microcrystals made via anti-solvent diffusion method. The use of polystyrene (PS) matrix helps the growth of environmentally stable BALI nanocrystals as a result of polymer capping. Optimization of the ratio of BALI-PS during the self-assembly process leads to the formation of defect-free composite microspheres. Further, these BALI crystals act as an active material within the microsphere resonators that display whispering gallery modes (WGM). These WGMs are responsible for high optical storage energy of resonators evidenced by their Q-factor as high as ~1180. Two-dimensional finite difference time-domain calculation shows the concentration of the electric field near the microspheres boundary within a small mode volume of 1.83 μm3. Remarkably, BALI-PS composite microresonators and their neat crystals exhibit brilliant two-photon luminescence upon excitation by the infrared fundamental radiation. This simplistic microresonators fabrication technique provides a route towards low-cost non-linear optical microlasers and other optical energy devices useful for various applications.
关键词： non-linear optical properties,perovskite,optical microresonators,polymer microspheres,two-photon emission
更新于2025-09-10 09:29:36