Porous Polymer Nanocomposites from Ethyleneamine–Poly(ethylene glycol) Diacrylate and Metal Oxide Nanoparticles: Morphology and Property Control

Porous polymer nanocomposites incorporating metal oxide nanoparticles (SiO2, ZrO2, and TiO2) were synthesized via the aza–Michael addition reaction of ethyleneamines with poly(ethylene glycol) diacrylate (PEGDA) under polymerization-induced phase-separation conditions. The resulting nanocomposites exhibited interconnected particulate morphologies with particle diameters ranging from less than 0.5 to 5.0 μm. Increasing the nanoparticle content led to a significant reduction in particle size, indicating that the nanoparticles influenced the phase-separation process and the development of the porous structure. Energy-dispersive X-ray spectroscopy confirmed the homogeneous distribution of nanoparticles throughout the polymer matrix. The refinement of the porous morphology increased the bulk density and consequently enhanced the Young’s modulus of the nanocomposites. In addition, porous nanocomposites containing SiO2 nanoparticles exhibited distinct coloration when immersed in toluene owing to the Christiansen filter effect. The transmission wavelength shifted toward longer wavelengths with increasing SiO2 content, which was attributed to a decrease in the effective refractive index of the porous nanocomposites. These results demonstrate that the incorporation of metal oxide nanoparticles provides an effective strategy for controlling the morphology, mechanical properties, and optical functionality of porous polymer nanocomposites.