Electroactive polymers (EAPs) present prospective use in actuation and manipulation devices due to their low electrical activation requirements, biocompatibility, and mechanical performance. One of the main drawbacks with EAP actuators is a decrease in performance over extended periods of operation caused by over-oxidation of the polymer and general polymer degradation. Synthesis of the EAP material, polypyrrole with an embedded metal helix allows for sequential growth of the polymer during operation. The helical metal electrode acts as a scaffolding to support the polymer, and direct the 3-dimensional change in volume of the polymer along the axis of the helix during oxidative and reductive cycling. The metal helix also provides a working metal electrode through the entire length of the polymer actuator to distribute charge for actuation, as well as for sequential growth steps during the lifetime of operation of the polymer. This work demonstrates the method of sequential growth can be utilized after extended periods of use to partially restore electrical and mechanical performance of polypyrrole actuators. Since the actuation must be temporarily stopped to allow for a sequential growth cycle to be performed and reverse some of the polymer degradation, these actuator systems more closely mimic natural muscle in their analogous maintenance and repair.
Electroactive polymers (EAPs) have emerged as viable materials in sensing and actuating applications, but the capability
to mimic the structure and function of natural muscle is increased due to their ability to permit additional, sequential
synthesis steps between stages of actuation. Current work is improving upon the mechanical performance in terms of
achievable stresses, strains, and strain rates, but issues still remain with actuator lifetime and adaptability. This work
seeks to create a bioinspired polymer actuation system that can be monitored using state estimation and adjusted in vivo
during operation. The novel, time-saving process of sequential growth was applied to polymer actuator systems for the
initial growth, as well as additional growth steps after actuation cycles. Synthesis of conducting polymers on a helical
metal electrode directs polymer shape change during actuation, assists in charge distribution along the polymer for
actuation, and as is described in this work, constructs a constant working electrode/polymer connection during operation
which allows sequential polymer growth based on a performance need. The polymer system is monitored by means of a
reduced-order, state estimation model that works between growth and actuation cycles. In this case, actuator stress is
improved between growth cycles. The ability for additional synthesis of the polymer actuator not only creates an
actuator system that can be optimized based on demand, but creates a dynamic actuator system that more closely mimics
natural muscle capability.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.