Combining Non-Self-Limiting Materials to Achieve Self-Limiting Electrospray Deposition

In the context of advanced materials, the increasing demand for high-performance materials that balance environmental sustainability and cost-effectiveness makes microscale coatings and thin films relatively desirable. One reliable method of creating these structures is electrospray deposition (ESD).

ESD is a manufacturing process in which a high voltage is applied to a flowing solution. If certain criteria are met, ESD can be transformed into a related process known as self-limiting electrospray deposition (SLED). For SLED to occur, solvent material must be insulating and below its glass transition temperature, and the substrate must be conductive. However, due to these conditions, not all materials innately exhibit the ability to be self-limiting. As a result, the aim of this work was to create blends of non-SLED materials such that the material characteristics could be manipulated to achieve SLED behavior.

Using ESD, we created coatings varying in composition of polyethylene glycol (PEG) and trehalose. In preliminary studies, it was found that solutions of pure PEG and pure trehalose do not result in self-limiting sprays; by blending the two materials together in a solvent system of 3:2 water:ethanol, it is hypothesized that the resulting material will be SLED. To test this, we tested different blends of PEG:trehalose, and measured the thickness of the coatings after smoothing with water vapor. Results were then compared to other known self-limiting materials to categorize the behavior of each blend.