Five key materials engineering components and how each component impacted the working performance of a polymer
actuator material are investigated. In our research we investigated the change of actuation performance that occurred
with each change we made to the material. We investigated polymer crosslink density, polymer chain length, polymer
gelation, type and density of reactive units, as well as the addition of binders to the polymer matrix. All five play a
significant role and need to be addressed at the molecular level to optimize a polymer gel for use as a practical actuator
material for biomedical and industrial use.
The concept is simple, within the pump a pH responsive polymer actuator swells in volume under electrically controlled
stimulus. As the actuator swells it presses against a drug reservoir, as the reservoir collapses the drug is metered out to
the patient. From concept to finished product, engineering this smart system entailed integration across multiple fields of
science and engineering. Materials science, nanotechnology, polymer chemistry, organic chemistry, electrochemistry,
molecular engineering, electrical engineering, and mechanical engineering all played a part in solutions to multiple
technical hurdles. Some of these hurdles where overcome by tried and true materials and component engineering, others
where resolved by some very creative out of the box thinking and tinkering. This paper, hopefully, will serve to
encourage others to venture into unfamiliar territory as we did, in order to overcome technical obstacles and successfully
develop a low cost smart medical device that can truly change a patient's life.
This paper discusses the development and system integration of the Pulse Activated Cell System (PACS) Digital
Pump technology using 2 types of electro-activated polymer (EAP) actuators. This is a platform specifically
developed for the integration of sensor feedback loops to create an autonomous fluidic monitoring, reaction and
delivery system. Initial, proof of concept, performance testing results are discussed as well as development for a
medical drug delivery device and higher volume infusion therapy device. Uses and applications of the technology in
other industries is considered as the PAC System provides a new ability to pump single or multiple fluid flows in a
single pump that is programmable with the ability to vary direction, pressure and flow rates. The result is digital
control of fluidic delivery, testing and mixing in application scaleable product packages. This technology will lead to
new low cost yet sophisticated fluidic processing products and devices for many industries.
For military applications, the availability of safe, disposable, and robust infusion pumps for intravenous fluid and drug
delivery would provide a significant improvement in combat healthcare. To meet these needs, we have developed a
miniature infusion prototype pump for safe and accurate fluid and drug delivery that is programmable, lightweight, and
disposable. In this paper we present techniques regarding inter-digitated IPMCs and a scaleable IPMC that exhibits
significantly improved force performance over the conventional IPMCs. The results of this project will be a low cost
accurate infusion device that can be scaled from a disposable small volume liquid drug delivery patch to disposable large
volume fluid resuscitation infusion pumps for trauma victims in both the government and private sectors of the health
Electroactuated polymer (EAP) hydrogels based on JEFFAMINE® T-403 and ethylene glycol glycidyl ether (EGDGE)
are used in an infusion pump based on the proprietary Pulse Actuated Cell System (PACS) architecture in development
at Medipacs LLC. We report here significant progress in optimizing the formulation of the EAP hydrogels to
dramatically increase hydrolytic stability and reproducibility of actuation response. By adjusting the mole fraction of
reactive components of the formulation and substituting higher molecular weight monomers, we eliminated a large
degree of the hydrolytic instability of the hydrogels, decreased the brittleness of the gel, and increased the equilibrium
swelling ratio. The combination of these two modifications to the formulation resulted in hydrogels that exhibited
reproducible swelling and deswelling in response to pH for a total period of 10-15 hours.
One drawback of Electro Active Polymer (EAP) materials for industrial actuation purposes is that the power needed to
scale up the technology is prohibitive both in the sheer magnitude and cost. The development of a reversible ionic
photo-activated polymer (IPAP) actuator material is a way to circumvent the prohibitive power needs and gain
industrial acceptance of polymer actuator materials. By doping electro active or ionic polymers with photo reversible
ionic sources it is possible to create similar response characteristics to that of ionic EAP actuators. The power needed
to drive a single light source would inherently be much less that needed to drive individual EAP actuators as size of
application increased, this reduction in power would also be multiplied by the number of actuators in a given system. It
is also theorized that the speed of actuation cycles would be increased by diffuse irradiation throughout the material.
Even more attractive is the possibility of the material being activated from natural daylight irradiation and the need for
electrical power eliminated.
A new array based Electro Activated Polymer (EAP) pump is explored with initial results and design considerations. By developing an array of EAP actuators that are digitally addressable and controlled it is possible to build a pump mechanism with programmable flow rates, pressure, flow direction and multiple flows. This design provides fluid flow by having a continuous pump chamber that consists of multiple voids or cells that are actuated to an open or closed position. When closed the fluid in the cell is displaced by the actuator and forced into the next sequential cell that is open. The unique Pulse Activated Cell System (PACS) array format provides the ability to pump in a programmable X & Y axis. We have targeted the first commercial application as a Programmable Disposable Drug Delivery Platform (PD<sup>3</sup>P).