Water‐Induced Separation of Polymers from High Nanoparticle‐Content Nanocomposite Films
Baekmin Q. Kim, Máté Füredi, R. Venkatesh, Stefan Guldin, Daeyeon Lee
Abstract
Abstract Polymer nanocomposites with high loadings of nanoparticles (NPs) exhibit exceptional mechanical and transport properties. Separation of polymers and NPs from such nanocomposites is a critical step in enabling the recycling of these components and reducing the potential environmental hazards that can be caused by the accumulation of nanocomposite wastes in landfills. However, the separation typically requires the use of organic solvents or energy‐intensive processes. Using polydimethylsiloxane (PDMS)‐infiltrated SiO 2 NP films, we demonstrate that the polymers can be separated from the SiO 2 NP packings when these nanocomposites are exposed to high humidity and water. The findings indicate that the charge state of the NPs plays a significant role in the propensity of water to undergo capillary condensation within the PDMS‐filled interstitial pores. We also show that the size of NPs has a crucial impact on the kinetics and extent of PDMS expulsion, illustrating the importance of capillary forces in inducing PDMS expulsion. We demonstrate that the separated polymer can be collected and reused to produce a new nanocomposite film. The work provides insightful guidelines on how to design and fabricate end‐of‐life recyclable high‐performance nanocomposites.