Table 3.

Selected examples of applications and relevant features for several polymer–inorganic oxide nanocomposites.

Application	Nanocomposite System	Features	Reference
Electrical insulation	Epoxy–SiO2 Epoxy–TiO2	Increased dielectric breakdown strength Decreased complex permittivity Increased Tg Increased strength, toughness, ductility	[16,18,108,116,117,118,119,120]
	PE 1–MgO PE–Al2O3	Decreased DC conductivity Increased dielectric breakdown strength Decreased space charge accumulation Decreased complex permittivity	[121,122,123,124,125]
	PI 2–SiO2	Decreased electrical conductivity Increased scratch hardness Increased strength	[126]
Fuel cells	Nafion–TiO2 Nafion–SiO2	Increased water uptake Decreased resistivity Increased Tg Increased degradation temperature	[105,127,128]
	PVA 3–SiO2	Increased liquid retention Increased proton conductivity Higher ion-exchange capacity	[129,130]
	PVDF 4–Al2O3	High proton conductivity High thermal stability Low methanol permeability Increased water uptake	[131]
Coatings	Epoxy–SiO2	Increased flame retardance High Tg Good thermal stability	[132]
	PDMS–TiO2–SiO2	Transparent and hydrophobic Increased hardness	[68]
	Epoxy–SiO2 Epoxy–Fe2O3	Improved corrosion resistance Increased Young’s modulus	[133]
	PDMS–PVA–ZnO	Decreased hydrophobicity Reduced contamination by fluorescent biomarkers in biosensors	[134]
	Epoxy–PANI 5–ZnO	Antifouling and antibacterial properties	[135]
Bioactive materials	PDMS–CaO–SiO2–TiO2	Increased Young’s modulus High apatite-forming ability High extensibility High strength	[33,111]
	PDMS–CaO–SiO2	High apatite-forming ability Decreased release of silicon in body fluids Mechanical properties analogous to those of human cancellous bones	[110]
Solid electrolytes	PEO 6–SiO2	Increased Li+ transference number Increased Tg	[88]
	PEG–PU/PAN 7 with TiO2	Good thermal stability Increased ionic conductivity	[114]
Ultrafiltration	PS8–TiO2	Increased hydrophilicity Increased permeability Increased Tg	[101]
Electromagnetic interference shielding (EMI)	PANI–SiO2	Increased EMI shielding effectiveness Increased thermal stability	[93]

¹ Polyethylene; ² Polyimide; ³ Poly(vinyl acetate); ⁴ Poly(vinylidene fluoride); ⁵ Polyaniline; ⁶ Poly(ethylene oxide); ⁷ Poly(ethylene glycol) –polyurethane/poly(acrylonitrile); ⁸ Polystyrene.