A very convenient one-step synthesis to cross-linked polymeric nanoparticles by conventional radical copolymerization without the addition of stabilizers or surfactants was explored. Moreover, these nanoparticles exhibited excellent stability, activity and selectivity in the cycloaddition reaction of CO₂ to epoxides and could be separated from the products easily and reused.

A solar actuator is fabricated by incorporating sunlight-responsive azobenzene into agarose and the sunlight-induced motion is utilized for electricity generation.

Highly cross-linked polymeric nanoparticles (CLPNs) were prepared via a facile one-step synthesis, and these nanoparticles are effective catalysts for CO₂ cycloaddition with epoxides. In this study, CLPNs were synthesized by radical copolymerization of 4-vinylbenzyl-tributylphosphorous chloride (PIL) and ethylene glycol dimethacrylate (EGDMA) in selective solvent, such as C1∼C5 alcohols. The results revealed that spherical nanoparticles with the mean diameter range of 10–100 nm could be prepared in these alcohols, and the size of the CLPNs could be facilely tuned by the feed ratio of EGDMA to PIL. The CLPNs were characterized using dynamic light scattering, scanning electron microscopy, transmission electron microscopy, atomic force microscopy, thermogravimetric analysis, atom absorbance spectrometry, and Fourier transform infrared spectroscopy techniques. In addition, CLPNs can be exploited as highly active and selective catalyst for the cycloaddition of CO₂ to epoxides. The effects of parameters, such as reaction temperature, pressure, reaction time, and catalyst amount, on the cycloaddition reaction were investigated. As a result, excellent yield (100%) and selectivity (100%) of cyclic carbonates could be achieved under mild conditions (0.1 g CLPNs, 3.0 MPa CO₂, 140 °C and 3 h) without the addition of any solvents or co-catalysts. Unexpectedly, the CLPNs could be dispersed in the products homogeneously, which resulted in the extremely high activity and selectivity. At the same time, the CLPNs could be easily separated by filtration after pouring the reaction mixture into toluene. CLPNs could be recycled six times with less than 1.5% loss of catalytic activity.