MOE Key Laboratory of Macromolecular Synthesis and Functionalization, Department of Polymer Science and Engineering, Key Laboratory of Adsorption and Separation Materials and Technologies of Zhejiang Province, Zhejiang University , 38 Zheda Road, Hangzhou 310027, P. R. China.
ACS Nano. 2017 Oct 24;11(10):9663-9670. doi: 10.1021/acsnano.7b03480. Epub 2017 Sep 5.
The 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.
层层组装方法已被广泛用于在基底上通过多个循环来制备多层涂层，然而，高效地制备厚膜却很困难。在这里，我们开发了一种离子扩散导向组装（IDDA）策略，可在一步中快速在任意基底上制备多层厚涂层。为了实现多功能涂层，氧化石墨烯（GO）和金属离子分别被选为 IDDA 中的典型构建块和扩散导向剂。由于金属离子从基底自发扩散到带负电荷的 GO 分散体中（即从高浓度区域到低浓度区域），GO 通过溶胶-凝胶转化逐片组装到基底上。由于亚纳米尺寸的金属离子可以在水相中定向和自由扩散，GO 可以高效地涂覆在基底上，从而得到每循环厚度达到 10 μm 的所需厚度的薄膜。IDDA 方法具有三个主要优点：（1）高效率，涂层速率达到 μm 级；（2）厚度和均匀性可控；（3）通用性强，适用于任何形状和形态的塑料、金属和陶瓷基底。凭借这些优点，IDDA 策略被用于高效制备具有优异超级电容器性能、电磁干扰屏蔽纺织品和防腐涂层的功能化石墨烯涂层。这种 IDDA 方法可以扩展到其他构建块，包括聚合物和胶体纳米粒子，有望实现多功能涂层的规模化生产和应用。
