Bicontinuous PMMA/SiO2 Nanonetworks with Reinforced Interfacial Strength as Mechanical Metamaterials from Block Copolymer-Templated Syntheses

Traditional inorganic materials usually possess high stiffness but suffer from low impact property, whereas polymeric materials exhibit excellent ductility but relatively low stiffness. This study aims to suggest a bottom-up approach that integrates the merits of inorganic (SiO₂) and organic (PMMA) components to fabricate nanohybrids with a bicontinuous nanonetwork structure via templated syntheses using self-assembled polystyrene-b-polydimethylsiloxane (PS-b-PDMS) as a template. The resultant nanonetwork SiO₂ exhibits excellent energy absorption due to its deliberate structuring as mechanical metamaterials. Subsequently, PMMA/SiO₂ can be fabricated through templated polymerization using the fabricated SiO₂ as a template, enabling a balance between stiffness and toughness through hybridization effect. The mechanical performance of the nanohybrids can be further enhanced by strengthened interfacial interaction between PMMA and SiO₂ via grafting. The superior mechanical properties arise from the combined effects of topology, nanosize, hybridization, and interfacial reinforcement. This study provides design insights for nanohybrids materials with inorganic networks embedded in polymer matrix to optimize the mechanical performace from the balance of stiffness and toughness.