nn7b03480_si_001.pdf (503.31 kB)
Ion Diffusion-Directed Assembly Approach to Ultrafast Coating of Graphene Oxide Thick Multilayers
journal contribution
posted on 2017-08-29, 00:00 authored by Xiaoli Zhao, Weiwei Gao, Weiquan Yao, Yanqiu Jiang, Zhen Xu, Chao GaoThe
layer-by-layer (LbL) assembly approach has been widely used
to fabricate multilayer coatings on substrates with multiple cycles,
whereas it is hard to access thick films efficiently. Here, we developed
an ion diffusion-directed assembly (IDDA) strategy to rapidly make
multilayer thick coatings in one step on arbitrary substrates. To
achieve multifunctional coatings, graphene oxide (GO) and metallic
ions were selected as the typical building blocks and diffusion director
in IDDA, respectively. With diffusion of metallic ions from substrate
to negatively charged GO dispersion spontaneously (i.e., from high-concentration region to low-concentration
region), GO was assembled onto the substrate sheet-by-sheet via sol–gel transformation. Because metallic ions
with size of subnanometers can diffuse directionally and freely in
the aqueous dispersion, GO was coated on the substrate efficiently,
giving rise to films with desired thickness up to 10 μm per
cycle. The IDDA approach shows three main merits: (1) high efficiency
with a μm-scale coating rate; (2) controllability over thickness
and evenness; and (3) generality for substrates of plastics, metals
and ceramics with any shapes and morphologies. With these merits,
IDDA strategy was utilized in the efficient fabrication of functional
graphene coatings that exhibit outstanding performance as supercapacitors,
electromagnetic interference shielding textiles, and anticorrosion
coatings. This IDDA approach can be extended to other building blocks
including polymers and colloidal nanoparticles, promising for the
scalable production and application of multifunctional coatings.