We evaporate aqueous suspensions in a microchamber to explore the connection between the morphology of the nanoparticle deposits at nanometer resolutions and at micrometer and hundreds of micrometers resolutions. Repulsive or weakly attractive electrical double-layer and van der Waals surface forces render the deposition of detached particles and small aggregates at nanometer resolutions. However, strongly attractive surface forces render the dense deposition of large aggregates. At greater length resolutions, the deposit morphology is further governed by evaporation-mediated transport of particles in the volatile suspension. We use experiment and theory to show that the contributions of the different mechanisms to the deposit morphology are mediated by particle coagulation and by particle adsorption to the substrate. The nanometer deposit morphology and particle transport render the morphology of the deposits at greater length resolutions, where it may take the shape of crude or smooth particulate micropatterns or continuous particulate coating layers.

The fabrication and implementation of artifi cially intelligent sensor arrays has faced serious technical and/or cost-effectiveness challenges. Here, a new printing method is presented to produce a fully functional array of sensors based on monolayer-capped gold nanoparticles. The proposed printing technique is based on the so-called self-propelled antipinning ink droplet, from which evaporative deposition takes place along the path of motion. By applying actuating forces, different deposition line patterns with different thicknesses and morphology from a single droplet are generated. The functionality of the produced sensors is demonstrated by their ability to detect different representative volatile organic compounds (VOCs) belonging to different chemical families, including alcohols, alkanes, ethers, and aromatics, and under extremely different humidity levels resembling those encountered in real-world conditions. The results show that the sensors exhibit ultrasensitive sensing features, with an ability to detect and differentiate between different VOCs at low ppb levels. Additionally, the results show that the sensors are able to accurately predict VOC concentrations, viz. enable quantifi cation capabilities, while nevertheless being inexpensive, do not need complicated and expensive printing equipment and prepatterning processes, allow low voltage operation, and provide a platform for multifunctional applications.

The capacity of nanoparticles to self‐arrange to various structures and their unique physical properties has made these building blocks essential in a broad range of applications and scientific disciplines. In this work, the manipulation of particulate structures that appear from binary dispersions is demonstrated, comprising same size particles of two different chemistries, following the evaporation of an electrolyte solution carrier. By varying the ionic strength and pH in the solutions, the balance between attractive and repulsive surface forces is tuned, that is, electrical double layer, Van der Waals, hydrophobic, and hydrophilic forces, in the binary particle mixtures. Hence, the corresponding potential energy barriers are tuned to particle attachments to each other and to the underlying substrate and alter the nanoscopic arrangement of the different types of particles in the microscopic particulate structures, which appear by convective pattern formation. Hence, by realizing the physical mechanisms which govern the potential energy contributions to the pattern formation of particulate structures at the nanometer scale, the 3D morphology of binary mixtures of same size particles is rendered homogeneous, layered, or phases separated. This is a useful approach toward the top‐down fabrication of nonhomogeneous colloidal structures.

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