Date of Completion

8-10-2020

Embargo Period

8-10-2021

Advisors

Jeffrey R. McCutcheon, Kelly A. Burke, Baikun Li

Field of Study

Chemical Engineering

Degree

Master of Science

Open Access

Open Access

Abstract

This thesis deals with the scope and prospects of the novel technology for electrospray printing to process polymers for liquid filtration membrane applications. First, the ability to explore novel reaction media to tune polyamide properties was demonstrated. Aromatic polyamides for reverse osmosis membranes are made by interfacial polymerization. Conventionally, interfacial polymerization is an in situ polycondensation of a diamine and an acid chloride conducted on a porous support at the interface of two immiscible solvents. Using electrospray printing, different solvent media were used to print polyamides on to ultrafiltration support membranes. It was observed that polar protic solvents formed membranes with moderate to high rejections and polar aprotic solvents formed membranes with high permeance and low rejections. Membranes made with 50% v/v methanol aqueous mixture performed well with water permeance and salt rejection comparable to some reported interfacially synthesized polyamides. These results can be used to tailor polyamide properties for membranes for different liquid filtration applications. Second, this technique was used to process zwitterionic copolymer into ultra-thin membrane selective layers. Membranes made by electrospray printing had exceptionally high permeances of 205 LMH/bar whereas membranes made by the conventional process of solvent casting had permeances of 5.9 LMH/bar. These membranes exhibited rejections similar to the membranes made by the conventional methods. Third, the ability of additive electrospray printing was demonstrated to form composite membranes. An ultra-thin zwitterionic copolymer film with high permeability was printed as an anti-fouling coating on commercial membranes to increase their lifetime. However, the organic solvent-polyamide interaction reduced the permeance of these composite membranes. This was mitigated by a simple post-treatment washing step. This work describes the advantages of moving to electrospray printing for polymer processing for membrane applications.

Major Advisor

Jeffrey R. McCutcheon

Available for download on Tuesday, August 10, 2021

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