Papers by Author: Zhi Jiang Cai

Abstract: Poly(3-hydroxybutyrate-co-4-hydroxybutyrate) (P3HB-co-4HB) nanofiber membranes were papered via electrospinning from polymer solution. The electrospinning parameters such as solution concentration, feed rate, applied voltage, collection distance were optimize in order to reduce fiber diameter and distribution. The nanofiber membrane was characterized by SEM, FTIR, DSC, XRD and tensile test. According to SEM results, the averaged diameter and distribution of nanofibers could be reduced down to 454nm and 0.191, respectively. The DSC and XRD results indicated that the crystallization regularity was improved and the range of melting temperature decreased due to the orientation of molecular chains along the fiber axis. The electrospun P3HB-co-4HB nanofiber membranes was flexible but easy broken.

Abstract: This paper describes a new electro-active actuator based on cellulose and poly(3-hydroxybutyrate) (PHB) blend film that can produce high bending displacement in room humidity condition. Cellulose based actuator has been reported as a smart material that has merits in terms of lightweight, dry condition, biodegradability, sustainability, large displacement output and low actuation voltage. However, its actuator performance is very sensitive to humidity, which requires high humidity condition for the maximum actuator performance. To overcome this drawback, we introduce cellulose-PHB blend film based actuator. To fabricate this new actuator, cellulose and PHB were dissolved in trifluoroacetic acid. The solution was cast to form a film followed by depositing thin gold electrode on both sides of the film. The morphology of the blend was characterized by scanning electron microscopy. The actuator can be actuated under AC voltage. The bending performance was evaluated in terms of free bending displacement, electrical power consumption output with respect to voltage and frequency and lifetime test at ambient condition. Primary results show that this cellulose- PHB blend actuator is less sensitive to humidity and it shows much high bending displacement and long lifetime (more than 10 hours) at room humidity condition. These results indicate that this new cellulose-PHB blend actuator is promising for many biomimetic applications in foreseeable future.

Abstract: In this paper, electro-active actuator made with cellulose and polyurethane blend film is prepared, which can show high bending displacement in the air with room humidity condition. To fabricate this actuator, cotton cellulose was dissolved into a N,N-dimethylacetamide (DMAc) and lithium chloride (LiCl) solvent system. Polyurethane prepared by poly[di(ethylene glycol) adipate] and hexamethylene diisocyanate (HDI) was mixed with DMAc cellulose solution by stirring. The mixed solution was cast to form a film followed by depositing thin gold electrode on both sides of the film. The actuator was actuated under AC voltage at an ambient condition by changing the actuation voltage, frequency and time. The actuator revealed a large bending displacement under low activation voltage, low electrical power consumption and good durability at room condition. This cellulose- polyurethane blend actuator is suitable for dry and durable actuator and promising for many biomimetic applications in foreseeable future.