Date of Graduation

5-2024

Document Type

Thesis

Degree Name

Bachelor of Science in Mechanical Engineering

Degree Level

Undergraduate

Department

Mechanical Engineering

Advisor/Mentor

Shou, Wan

Committee Member

Walters, Keith

Abstract

While perfluorosulfonic acid (PFSA) membranes have primarily been used in fuel cells due to their chemical, thermal, and mechanical stability, one PFSA, Nafion, boasts two unique characteristics: a broad glass transition (~55 °C to 130 °C) and a temperature-persistent electrostatic network. The combination of these two characteristics endows Nafion with exceptional shape memory properties – the ability of a material to morph and transform into pre-programmed shapes when exposed to an external stimulus – with enhanced permanent shape memorization, and a potentially near-infinite number of temporary shape memorization. This study focused on expanding the base of knowledge surrounding Nafion’s shape memory properties in different geometries and environments. Results have shown that as deformation/recovery temperature decreases below 100 °C, the time required to achieve an adequate recovery percentage (>95%) drastically increases, whereas at or above 100 °C, that time decreases below one minute. Surprisingly, varying the geometry of the material showed very little change in the recovery time and percentage. Furthermore, increasing the strain during testing also does not affect the shape memory behavior. Finally, processing samples with a blue laser at different power levels and in different directions did not affect the shape memory recovery percentage either. This study found that Nafion’s shape memory property is extremely robust, and its enhanced abilities vastly improve upon existing shape memory alloy and polymer functionality and expand the range of applications for Nafion, as many movements can be achieved in one cycle – lending applicability to uses such as deployables, actuators, sensors, and smart adhesives, particularly for in-space uses.

Keywords

Shape Memory Polymer; Deployables; Actuators; Nafion

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