Polymer-Infiltrated Nanoparticle Films Using Capillarity-Based Techniques: Toward Multifunctional Coatings and Membranes

Abstract

Polymer-infiltrated nanoparticle films (PINFs) are a new class of nanocomposites that offer synergistic properties and functionality derived from unusually high fractions of nanomaterials. Recently, two versatile techniques,capillary rise infiltration (CaRI) and solvent-driven infiltration of polymer (SIP), have been introduced that exploit capillary forces in films of densely packed nanoparticles. In CaRI, a highly loaded PINF is produced by thermally induced wicking of polymer melt into the nanoparticle packing pores. In SIP, exposure of a polymer–nanoparticle bilayer to solvent vapor atmosphere induces capillary condensation of solvent in the pores of nanoparticle packing, leading to infiltration of polymer into the solvent-filled pores. CaRI/SIP PINFs show superior properties compared with polymer nanocomposite films made using traditional methods, including superb mechanical properties, thermal stability, heat transfer, and optical properties. This review discusses fundamental aspects of the infiltration process and highlights potential applications in separations, structural coatings, and polymer upcycling—a process to convert polymer wastes into useful chemicals.

Modulating Interactions between Molten Polystyrene and Porous Solids Using Atomic Layer Deposition

“…To infer the contact angle of PS on ALD-treated pore surfaces, we use the reported value of 20°for the contact angle of PS on untreated SiO 2 NP (θ SiO2 in eq 3). 2,15,35 The change in the pore size (R pore,ALD ) induced by ALD is less than 1 nm, which is less than 10% of the average pore radius in the NP packing. Contact angle (θ ALD ) of PS on the ALD-modified pore surface of NP films is inferred by measuring the time of infiltration (t ALD ) while taking into account the change in the size of the pore due to ALD.…”

“…1 A particularly important example involves nanoparticle (NP)−polymer composite films and membranes with extremely high filler fractions of NPs prepared via capillary rise infiltration of polymers into packings of NPs. 2,3 These polymer-infiltrated NP films possess superb mechanical, 4,5 anti-corrosion, 6 and thermal transport properties. 7−9 Diffusion of polymer chains into porous solids can also play an important role in the catalytic reactions involved in polymer upcycling.…”

“…Our prior publications have provided SEM images of such bilayers after infiltration. 2,3,27 2.5. Contact Angle Determination on ALD-Treated Samples.…”

“…The bilayer is heated to 423 K to induce capillary rise infiltration of PS into the interstices of ALD-modified SiO 2 NP films. The infiltration time is measured by monitoring the changes in the amplitude ratio (Ψ) and phase difference (Δ) of the polarization between the incident and reflected light as a The contact angle of PS on the ALD-modified pores of SiO 2 NP films is inferred using the Lucas−Washburn equation, 2,31,32 which describes the dependence of the height of capillary rise of a liquid in a porous medium (h) on the surface tension (γ PS-G ), pore size (R pore ), contact angle (θ), liquid viscosity (μ), tortuosity (τ), and time (t) (see the Supporting Information for the value used for each parameter)…”

“…Infiltration and motion of molten polymers in nanoporous solids have important implications in several important phenomena and processes . A particularly important example involves nanoparticle (NP)–polymer composite films and membranes with extremely high filler fractions of NPs prepared via capillary rise infiltration of polymers into packings of NPs. , These polymer-infiltrated NP films possess superb mechanical, , anti-corrosion, and thermal transport properties. − Diffusion of polymer chains into porous solids can also play an important role in the catalytic reactions involved in polymer upcycling. − The infiltration and transport of polymer chains in nanoscale pores depend strongly on the wetting characteristics of the polymer on the pore surface and on the polymer–pore surface interactions. ,− Molecular dynamics simulations, for example, , have shown that the dynamics of polymer infiltration into nanopores, as well as the final structure and mechanical properties of the composite prepared using such a process, depend strongly on the polymer–surface interactions. It is, however, difficult to change the surface composition of the solid without also changing the size and shape of the pores.…”