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Simultaneous “Clean‐and‐Repair” of Surfaces Using Smart Droplets
Author(s) -
Sathyan Ashlin,
Yang Zhefei,
Bai Ying,
Kim Hyunki,
Crosby Alfred J.,
Emrick Todd
Publication year - 2019
Publication title -
advanced functional materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.069
H-Index - 322
eISSN - 1616-3028
pISSN - 1616-301X
DOI - 10.1002/adfm.201805219
Subject(s) - materials science , substrate (aquarium) , polymer , pulmonary surfactant , adsorption , chemical engineering , nanotechnology , nanoparticle , drop (telecommunication) , biofouling , microfluidics , fouling , rheology , emulsion , membrane , composite material , chemistry , organic chemistry , computer science , telecommunications , biochemistry , oceanography , engineering , geology
An autonomous self‐healing system, inspired by transportation processes inherent to biology, is described for materials transportation and repair. The selected model system combines inorganic nanoparticles (NPs) on damaged substrates with functional emulsion droplets that pick up the particles from pristine portions of the substrate and deposit them into damaged regions. The droplets are stabilized by polymer surfactants containing phosphorylcholine groups, a polymer composition selected to impart surfactant properties for droplet stabilization as well as fouling resistance to prevent irreversible droplet adsorption on the substrates. Both the NP pickup (cleaning) and drop off (repair) steps are conducted in a system driven by an imposed flow and characterized by fluorescence microscopy. To evaluate and optimize the efficiency of this NP transportation process, the effect of both the chemical composition of the polymer surfactant and the NP surface chemistry is investigated. Interfacial interactions proved enabling for these NP transportation processes, specifically those involving NP/droplet, NP/substrate, and droplet/substrate interactions. Ultimately, droplets capable of both picking up and dropping off NPs are realized by adjusting fluid/fluid and fluid/substrate interactions, with electrostatic interactions between NPs and droplets proving most effective.