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A new method for prototype of a three dimensional (3 D) microfluidic device on piezoelectric substrate was presented. Wires were stick by colloidal starch, and dried in a thermotank for three dimensional channels mold. The mold was slightly placed in a groove with poly(dimethylsiloxane). After having been solidified, these wires were drawn off to form 3 D microchannels. Surface acoustic wave was used to driven sample droplet to the inlet of the microchannel in microfluidic device. Red fluid transportation in different microchannels was successfully demonstrated using the 3 D microfluidic device at 24.5 dBm signal power for verifying the function of the microfluidic device. [ABSTRACT FROM AUTHOR]

A method for spatial transportation of a droplet was presented. Spatial transporting characteristic was theoretically analyzed. The droplet on an YX-128° LiNbO3 piezoelectric substrate was exerted the acoustic streaming force and resistance from a steel ball with 2 mm diameter, which was fixed on the piezoelectric substrate by help of polydimethylsiloxane (PDMS). The droplet was then transported along the spherical surface. Experimental results show that spatial transportation height is relied on the size of the droplet and the power of an electric signal. 1.5 µl red ink droplet can be transported to the ball top at 30.8 dBm electric signal power. [ABSTRACT FROM AUTHOR]

A new method for heating microfluid in a polydimethylsiloxane (PDMS) array chip is presented. Interdigital transducers are fabricated on a 128° YX-LiNbO3substrate. A 4 × 4 polydimethylsiloxane array chip is placed on the piezoelectric substrate, where a heat transfer pillar with a heat transfer sheet is connected with every reaction zone in the PDMS array chip. An oil droplet is driven for selecting special heat transfer pillar to heat the microfluid in the special reaction zone. Theoretical calculation of heat transfer is finished. At equilibrium state, the emitted energy per second during heat transfer is 7.436 mJ at 30.0 dBm electric signal power. [ABSTRACT FROM AUTHOR]

A new method for splitting droplets in a channel was presented. Two interdigital transducers were fabricated on a 1280yx-LiNbO3substrate using microelectrical technology. A poly (dimethylsiloxane) (PDMS) channel with PVC sheet and a PDMS block was mounted on the piezoelectric substrate. Surface acoustic waves were used to change the volume ratio of the split daughter droplets. Splitting experiments were done using red aqueous droplets in paraffin oil. Results show that surface acoustic waves can affect the ratio of split daughter droplets. A PDMS block in one of the daughter microchannels can obviate the remerging of daughter droplets. The work is helpful for microfluidic analysis on piezoelectric microfluidic devices. [ABSTRACT FROM AUTHOR]