Virginia Commonwealth University

Daren Chen

Hong Zhao

Qiaoling Liu

Systems, devices, and methods employ advantages of ultrasonic vibration in the field of electrospinning. Fibers are produced from an ultrasonic nozzle exposed to an electric field established between the nozzle and a target object. Exemplary embodiments include electrospinning techniques that produce fine and ultrafine fibers in a high throughput via multiple jetting of spun solutions and melts. Ultrasonic vibration, in some instances combined with heating, reduces the voltage required for spinning. Vibrating power delivered to the nozzle may be selected so gas bubbles are generated by solvent cavitation in the spun solution. The bubbles are generated at the nozzle exit or else in such positions of the solution path so as to reach the nozzle exit where they further enhance multiple jetting of spun solutions.

Ultrasonic electrospinning for the production of fine and ultrafine fibers

An electrohydrodynamic (EHD) jet printing apparatus or system may include circulation of printing fluid to minimize or eliminate clogging in a nozzle. An exemplary nozzle comprises at least two ink channels&#x2014;one allowing flow to a droplet emitting opening and one allowing flow away from the droplet emitting opening&#x2014;configured for circulating ink. The nozzle may transfer ink to a substrate with an EHD technique involving voltage or current modulation. For example, an electric field may be applied between the nozzle and printing substrate such that the ink meniscus changes shape and releases ink from the tip of the liquid cone. A multi-channel nozzle may take a variety of configurations, including two co-axially aligned capillaries, side-by-side parallel capillaries, or capillaries arranged at an angle with respect to one another but converging at a single point where the conical meniscus is formed.

Dual channel jetting apparatus for 2D/3D electrohydrodynamic (EHD) printing

A particle electrical mobility classifier is provided for the classification of particles (e.g., particles less than 1 &#x3bc;&#x3b9;&#x3b7; in size) based on their electrical mobility. The particle classification zone is curved. In an exemplary embodiment, two metal concentric cylinders, separated by an annular insulation spacer, establish a particle classification zone. A DC electrical field is supplied by the cylinders in the circular classification zone. An example classifier can be operated in different modes such as: (1) as a particle precipitator; (2) as a particle electrical mobility separator, and (3) as a differential mobility classifier. The curved classification zone results in a particle classifier having an extended particle sizing range as compared to their counterparts in classical configurations. The curve of the classification channel (in the flow direction) may be in any of several configurations (e.g., circular, wavy, spiral, or helical).

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Glen Allen, VA, United States of America

Daren Chen