研究目的
To address the limitation of organic polymerization in achieving high concentrations of inorganic components in hybrid materials by developing a high-pressure-ramp process for synthesizing pHEMA–TiO2 hybrids with enhanced structural and photochromic properties.
研究成果
The HPR process enables synthesis of pHEMA–TiO2 hybrids with unprecedented inorganic concentrations up to 12 mol l?1, exhibiting strong photochromic response and high electron storage capacity (up to 1021 cm?3). Nanoparticles transition from amorphous to anatase with increasing concentration, affecting properties. The method shows promise for micro-optical and optoelectronic applications due to enhanced refractive index and light-induced modifications.
研究不足
The HPR process currently produces small sample volumes (e.g., diameter ~150 μm, thickness ~20 μm), limiting scalability. The conversion yield decreases with higher inorganic concentrations, and the electron storage capacity reduces upon nanoparticle crystallization. Further studies are needed to clarify the impact of crystallization on electron trapping.
1：Experimental Design and Method Selection:
The study uses a high-pressure-ramp (HPR) process for polymerization, involving compression to high pressures to form biradicals and promote polymerization. It includes synthesis of titanium oxo-alkoxy nanoparticles via sol-gel method, solvent exchange, and polymerization under controlled pressure conditions.
2：Sample Selection and Data Sources:
Hybrid solutions with varying TiO2 concentrations (
3：146 to 84 mol l?1) were prepared by mixing TOA colloids with HEMA. Samples were characterized using Raman spectroscopy, HRTEM, and pump-probe absorption measurements. List of Experimental Equipment and Materials:
Diamond anvil cell (DAC) for high-pressure experiments, Raman spectrometer (Horiba Jobin Yvon HR800), transmission electron microscope (JEOL2011 HRTEM), energy filtered transmission electron microscopy (Gatan Imaging Filter 2000), pump-probe setup for optical absorption. Materials include titanium tetra-iso-propoxide (TTIP), 2-propanol, HEMA, and AIBN initiator for comparative thermal polymerization.
4：Experimental Procedures and Operational Workflow:
Steps include nanoparticle synthesis, solvent exchange, HPR polymerization (compression to 7 GPa, reduction to
5：5 GPa for 5 min, release to 1 bar), sample recovery, and characterization via Raman, TEM, and optical absorption kinetics. Data Analysis Methods:
Raman spectra analyzed for conversion yield using band intensity ratios; HRTEM images for morphology and crystallization; pump-probe data fitted with a model for electron trapping kinetics.
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