Stretch to scatter: mechanically tunable haze in silica nanofibers - polymer composite films

High-haze materials have been widely used in optical and photonic applications, yet most exhibit fixed internal structures with static haze levels, limiting their adaptability across different usage scenarios. Here, we report a facile strategy to fabricate strain-dependent tunable high-haze films by blending silica nanofibers (NFs) into a polystyrene-block-poly(ethylene-ran-butylene)-block-polystyrene (SEBS) matrix. The composite SEBS/NF films exhibit increasing light scattering and haze with the NF content, reaching up to 94 %. Upon mechanical stretching, the absence of chemical bonding between the rigid NFs and flexible SEBS allows interfacial sliding, generating nanoscale cavities. These cavities significantly amplify the internal refractive index mismatch, leading to a reversible and strain-dependent enhancement of haze. In addition, the inherent hydrophobicity of SEBS promises environmental stability and anti-fouling properties, enabling robust performance in underwater conditions. Together, these features position the SEBS/NF films as promising candidates for multi-functional optical systems, including underwater light diffusers and adaptive light management devices.