Hydrophobic and Durable Adhesive Coatings Fabricated from Fluorinated Glycidyl Copolymers Grafted on SiO₂ Nanoparticles

To obtain durable adhesive, highly hydrophobic, and thermostable coatings, novel fluorinated glycidyl copolymers grafted on SiO₂ nanoparticles were prepared by SiO₂-Br initiating covalent adhesion of glycidyl methacrylate (GMA) and low surface free energy of dodecafluoroheptyl methacrylate (12FMA) via surface initiated atom transfer radical polymerization. In tetrahydrofuran solution, the obtained random-structured SiO₂-g-(PGMA-co-P12FMA) behaves with 120 ± 10 nm core-shell morphology as SiO₂-core (110 ± 10 nm) and (PGMA-co-P12FMA) shell (8 ± 2 nm). The films cast by these core-shell particles reveal stronger hydrophobic surfaces (SAC = 114-119°), higher resistance to water absorption (Δm = 2478 ng·Hz^-1·cm^-2), and harder viscoelasticity (ΔD/Δf = -0.379) compared to the SiO₂-g-PGMA film (SAC = 90°, Δm = 6153.7 ng·Hz^-1·cm^-2, and ΔD/Δf = -0.271) due to the accumulated fluorine-rich surface and increased surface roughness. The introduction of antiaging P12FMA obviously improves the durability of adhesive strength of SiO₂-g-(PGMA-co-P12FMA) (1.82 MPa) compared with that of SiO₂-g-PGMA (decreased from 1.92 to 1.56 MPa) during the humidity thermal aging cycles. Meanwhile, SiO₂-g-(PGMA-co-P12FMA) displays thermostability higher than that of both SiO₂-PGMA and PGMA-co-P12FMA, attributed to the contribution of SiO₂ and P12FMA. Therefore, it is believed that SiO₂-g-(PGMA-co-P12FMA) could be an excellent potential candidate for highly hydrophobic and durable adhesive coatings.