Self-assembly of nanoparticles into superlattices can be used to create hierarchically structured materials with tailored functions. We have used the surface sensitive quartz crystal microbalance with dissipation monitoring (QCM-D) technique in combination with video microscopy (VM) to obtain time-resolved information on the mass increase and rheological properties of evaporation-induced self-assembly of nanocubes. We have recorded the frequency and dissipation shifts during growth and densification of superlattices formed by self-assembly of oleic acid capped, truncated iron oxide nanocubes and analyzed the time-resolved QCM-D data using a Kelvin-Voigt viscoelastic model. We show that the nanoparticles first assemble into solvent-containing arrays dominated by a viscous response followed by a solvent-releasing step that results in the formation of rigid and well-ordered superlattices. Our findings demonstrate that QCM-D can be successfully used to follow self-assembly and assist in the design of optimized routes to produce well-ordered superlattices.

纳米粒子自组装成超晶格可用于创建具有定制功能的分层结构材料。我们已经将表面敏感性石英晶体微天平与耗散监测（QCM-D）技术与视频显微镜（VM）结合使用，以获取时间分辨的信息，以了解蒸发引起的纳米立方体自组装的质量增加和流变特性。我们已经记录了由油酸封端的，截短的氧化铁纳米立方体的自组装形成的超晶格的生长和致密化过程中的频率和耗散位移，并使用开尔文-沃格特粘弹性模型分析了时间分辨的QCM-D数据。我们显示，纳米颗粒首先组装成含溶剂的阵列，该阵列以粘性响应为主，随后是溶剂释放步骤，该步骤导致形成刚性且有序的超晶格。我们的发现表明，QCM-D可以成功地用于自组装，并协助设计优化路线以产生有序的超晶格。