Session: 03-09-03: Design of Engineering Materials

Paper Number: 99997

99997 - Engineered Nanosurfactants for Additive Manufacturing 

2D and 3D printing of nanomaterials have emerged as a powerful tool for fast prototyping of functional electronics and devices with complex architectures. Surfactant, as an active ingredient of inks, plays a significant role in many printing processes due to its ability of reducing the interfacial tension between solvents and nanoparticles (and thus improve the colloidal stability of nanomaterial inks). However, the residual of organic surfactants in printed devices, owing to their insulating nature, limits the overall functionalities of the nanomaterials, requiring harsh post-printing treatments such as thermal annealing. Therefore, one practical barrier to the large-scale application of nanoparticle-based inks is the development of compatible ink additives such that they may not compromise or even improve the performance of printed devices. Here, we reported a graphene quantum dot nanosurfactant that is able to stabilize graphene in aqueous dispersion via π-π stacking interaction. Such nanosurfactant-stabilized graphene system is readily printable using a commercial aerosol jet printer. In addition, the suitable band gap of graphene quantum dots enables the printed composite with intriguing optoelectrical activity. Taking advantage of the aerosol jet printing, the formulated composite ink can be directly printed on various types of substrates with multiple dimensions, allowing for the fast prototyping of 3D conformal UV sensors. Thanks to the reduced interfacial tension of inks enabled by nanosurfactants, the aqueous dispersions of graphene, MoS₂, WS₂, and h-BN nanosheets are colloidally stable and can be readily used in printing processes. While pristine particles without nanosurfactant stabilization tend to aggregate and sediment in a few hours, these 2D flakes with nanosurfactant have shown to be highly colloidal stable in water (up to months). Moreover, the electrostatic stabilization of ink materials by nanosurfactant is quantified using zeta potential measurements which reveal high surface charge values. Similar to small-molecule surfactants, the nanosurfactant-based printing technique enables the rapid fabrication of complex device structures with high spatial resolution. More importantly, nanosurfactant not only eliminates the prerequisite of thermal treatment for the removal of organic surfactants, but also becomes an integrated part of the printed device and results in unique functionalities and superior performances in printed 2D-crystal-based devices, including bandgap engineering, enhanced photoconductance of ink materials, and improved film robustness. The research offers a facile, versatile, and highly scalable alternative for printing 2D nanomaterials into functional devices, which is expected to find broad applications in sensors, energy conversion/storage devices, and flexible and wearable electronics.

Presenting Author: Minxiang Zeng Texas Tech University

Presenting Author Biography: Dr. Minxiang Zeng is an assistant professor in the Department of Chemical Engineering at Texas Tech University. He received his PhD in Chemical Engineering from Texas A&M University in 2018, followed by a postdoc study at the University of Notre Dame. His research interests include self-assembly of anisotropic materials, additive manufacturing of functional devices, and the development of engineered materials for energy and sustainability.

Authors:

Minxiang Zeng Texas Tech University