Chulsung Bae

A new homogeneous polymer support based on syndiotactic polystyrene and its application in palladium-catalyzed Suzuki–Miyaura cross-coupling reactions

Soluble syndiotactic polystyrene-supported triphenylphosphine (sPS–TPP) was synthesized by reacting borylated syndiotactic polystyrene with (4-bromophenyl)diphenylphosphine. A palladium catalyst, supported on sPS–TPP, effectively catalyzed Suzuki–Miyaura coupling reactions of aryl halides under homogeneous conditions. The polymer-supported palladium complex was recovered quantitatively by adding an equal volume of poor solvent to the polymer, and coupling products could be easily isolated by evaporating the solvents. The recovered polymer complex was reused several times without significant loss of activity.

Wireless actuation and control of ionic polymer–metal composite actuator using a microwave link

The ionic polymer–metal composite (IPMC), a type of electroactive polymer (EAP) actuator, has created a unique opportunity to design robots that mimic the motion of biological systems due to its soft structure and operation at a low voltage. Although this polymer actuator has strong potential for a next-generation artificial muscle actuator, it has been observed by many researchers that supplying actuation voltages in multiple locations is challenging. In robotic applications, a tethered operation is prohibited and the battery weight can be critical for actual implementation. In this research, the remote unit can provide necessary power and control signals to the target mobile robot units actuated by IPMCs. This research addresses a novel approach of using a wireless power link between the IPMC and a remote unit using microstrip patch antennas designed on the electrode surface of the IPMC for transmitting the power. Frequency modulation of the microwave is proposed to selectively actuate a particular portion of the IPMC where the matching patch antenna pattern is located. This approach can be especially useful for long-term operation of small-scale locomotion units and avoids problems caused by complex internal wiring often observed in various types of biologically inspired robots.

Sulfonated Polyamide Based IPMCs

In this study, we introduce a newly developed Ionic Polymer-Metal Composite (IPMC) family that is manufactured using a novel ionic exchange membrane-a randomly sulfonated fluoropoly(ether amide) (TFIPA-90)-as the base material. The thermal behavior and mechanical properties of the ionic polymer were probed by differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA). Electrochemical properties and the actuation performance of the TFIPA-90 based IPMCs were also investigated in this study. The stiffness of the TFIPA polymer was significantly higher than that of Nafion® and much noted at high temperatures (>100 oC). The thermal behavior of the TFIPA polymer also showed better stability than Nafion(R) at high temperatures due to the more rigid chemical structure of the ionomer. As an actuator, a new IPMC prepared from TFIPA-90 showed improved performance with rapid response time to the electric field and a large bending displacement. The TFIPA-based IPMC may be useful for microwave-driven robotic applications.