Interfacial properties of a ZnO/PTFE composite from density functional tight-binding simulations

• Published in: RSC advances 2024-10, Vol.14 (47), p.3597-3513
• Main Authors: Ryu, Chol, Ri, Jun-Gi, Kim, Yun-Sim, Rim, Chung-Hyok, Kim, Chung-Il, Yu, Chol-Jun
• Format: Article
• Language: English
• Subjects: Bonding strength; Chemical bonds; Chemistry; Density; Interfacial properties; Metal oxides; Modulus of elasticity; Molecular dynamics; Nanocomposites; Polytetrafluoroethylene; Superlattices; Tensile stress; Thickness; Zinc oxide
• ISSN: 2046-2069; 2046-2069
• DOI: 10.1039/d4ra06790h

Metal-oxide-reinforced plastic nanocomposites are widely used in high-tech industries, but the reinforcement mechanism of the metal oxide is not fully understood. Here we investigate the interfacial properties of a zinc-oxide-reinforced amorphous polytetrafluoroethylene (a-PTFE) composite as a prototype for such composites using superlattice modeling and density functional tight-binding molecular dynamics simulations. To study the ZnO/a-PTFE composites, the superlattice supercells are built using a ZnO (112&cmb.macr;0) surface supercell and a-PTFE layer with an experimental density of 1.8 g cm −3 and various thicknesses. Our calculations demonstrate that the binding energy between ZnO and a-PTFE is negative, indicating their attractive binding, and electron accumulation occurs in the middle space between ZnO and a-PTFE, as well as around ZnO, evidencing that the newly formed interfacial chemical bonds are partially covalent. We further reveal that the tensile stress and elastic moduli of the ZnO/a-PTFE superlattice increases with increasing ZnO fraction, with values placed between those of ZnO and a-PTFE, which confirms the enhancement of the mechanical strength of the composites by incorporating ZnO into the a-PTFE matrix. This work provides a design guideline for developing high-performance metal-oxide-reinforced plastic composites. We performed density functional tight-binding simulations of a ZnO/amorphous PTFE superlattice to reveal the interlayer binding strength, charge redistribution and enhancement of mechanical strength of the ZnO-reinforced PTFE plastic composites.