Photoresponsive and Magnetoresponsive Graphene Oxide Microcapsules Fabricated by Droplet Microfluidics

Abstract

Fluid compartmentalization by microencapsulation is important in scenarios where protection or controlled release of encapsulated species, or isolation of chemical transformations is the central concern. Realizing responsive encapsulation systems by incorporating functional nanomaterials is of particular interest. We report here on the development of graphene oxide microcapsules enabled by a single-step microfluidic process. Interfacial reaction of epoxide-bearing graphene oxide sheets and an amine-functionalized macromolecular silicone fluid creates a chemically cross-linked film with micronscale thickness at the surface of water-in-oil droplets generated by microfluidic devices. The resulting microcapsules are monodisperse, mechanically resilient, and shape-tunable constructs. Ferrite nanoparticles are incorporated via the aqueous phase and enable microcapsule positioning by a magnetic field. We exploit the photothermal response of graphene oxide to realize microcapsules with photoresponsive release characteristics and show that the microcapsule permeability is significantly enhanced by near-IR illumination. The dual magnetic and photoresponsive characteristics, combined with the use of a single-step process employing biocompatible fluids, represent highly compelling aspects for practical applications.

Core@double‐shell structured multifunctional phase change microcapsules based on modified graphene oxide Pickering emulsion

“…In recent years, the Pickering emulsion method, which uses solid particles instead of traditional surfactants as emulsifiers and stabilizes the emulsion, has gradually become an effective and economical strategy for preparing microcapsules. [27][28][29] Graphene oxide (GO), as the precursor of graphene, [30][31][32] has a typical amphiphilic structure. 33 The study on the wettability of GO found that its contact angle is 62 to 68 , which makes GO particles more resident in water rather than oil, and tends to be stable in O/W emulsion.…”

A review on application of graphene‐based microfluidics

“…et al reported on the development of GO microcapsules enabled by a single‐step microfluidic process. The dual magnetic and photoresponsive characteristics, combined with the use of a single‐step process employing biocompatible fluids, represented highly compelling aspects for practical applications . Shang et al fabricated GO fibers with a spindle‐knotted structure and photothermally responsive phase‐transition behaviours by combining spinning and emulsification procedures in microfluidics.…”

Microfluidic fabrication of polysiloxane/dimethyl methylphosphonate flame‐retardant microcapsule and its application in silicone foams

“…Z. X. Luo et al reported that well‐designed microcapsules were fabricated using a droplet‐based microfluidic technique for controlled drug release. G. Kaufman et al fabricated photoresponsive and magnetoresponsive graphene oxide microcapsules by droplet microfluidics. D.V.…”

“…Kaufman et al 33 In this work, an ultraviolet-curable (UV-curable) polysiloxane was synthesized. Then flame-retardant microcapsules with a DMMP cores and a UV-curable polysiloxane shells were fabricated by the approach of microfluidic.…”