In this paper, a new type of microfluidic pump that can be activated and controlled by a masked light source is presented. The actuation of this micropump is based on an optopiezoelectric composite. This composite is constructed by having one of the electrodes of a piezoelectric PVDF (polyvinylidene fluoride) polymer replaced by a layer of TiOPc (titanyl phthalocyanine) photoconductive coating and an ITO (indium-tin-oxide) transparent electrode. This layer of photoconductive electrode provides the capability to activate multiple locations of this optopiezoelectric composite independently using a masked light source and a single voltage source. To verify the feasibility of this concept, dual light-activated microfluidic pumps based on this optopiezoelectric composite are implemented and studied. Experimental results verify that two microfluidic pumps can be created by one optopiezoelectric composite and that each pump can be optically turned on and off independently or be turned on simultaneously. These results suggest that integrating an optopiezoelectric composite into a lab-on-a-chip system can reduce the size and the number of driving units significantly, since every operation can be done optically and only one driving source is needed. The equivalent circuit, design, and implementation of dual light-activated optopiezoelectric micropumps are discussed in this paper.

Aminopropyl-terminated polydimethylsiloxane (PDMS)-bisphenol-A polycarbonate block copolymers were synthesized by interfacial phosgenation reaction of 2,2-bis(4-hydroxyphenyl) propane (BPA) and aminopropyl-terminated PDMS. A new synthetic procedure shows better conversion yield of PDMS oligomer. IR, Si nuclear magnetic resonance spectra were used to identify the exact chemical structures of the PDMS-PC block copolymers. The conversions of PDMS of these copolymers were Ç 90% and independent of the PDMS content. The intrinsic viscosities, IV, [ h] studied were in the range between 0.23 and 2.25 dL/g in dichloromethane at 25ЊC with different reaction conditions. The intrinsic viscosity and the glass transition temperature decreased with increasing PDMS content at the same reaction temperature, while the melting flow indices increase with increasing PDMS content. Transparent and colorless films, which showed good oxygen-to-nitrogen permselectivity, could be cast from dichloromethane.

SYNOPSISPolycarbonate is prepared by the interfacial phosgenation and polycondensation of bisphenol A (BPA) in methylene chloride with caustic using triethylamine as a catalyst. In a typical batch reactor, where phosgenation and oligomerization proceed simultaneously, the critical process parameters are intermingled and are difficult to determine. Therefore, a semicontinuous process consisting of a series of static mixers for continuous phosgenation, followed by a batch reactor for oligomerization and polycondensation, was developed for better understanding of the reaction mechanisms. Phosgene hydrolysis was reduced greatly going from a batch to a continuous reactor (excess phosgene was reduced from 30 to 5% ) . Variables which influence the composition of intermediates are linear velocity, organic to aqueous volume ratio, P H (BPA to NaOH ratio), and phosgene to BPA ratio. These variables also affect BPA conversion, amount of phosgene hydrolysis, terminator capping efficiency, molecular weight, and molecular weight distribution of the resulted polycarbonate. Oligomerization takes place at the interface, and monochloroformates (HO-B,-OCOC1) which contain both hydrophilic and lipophilic end groups, stay at the interface and, hence, react preferentially. Oligomers are analyzed by a newly developed HPLC technique.

Polycarbonate-polydimethylsiloxane (PDMS) copolymers were synthesized by interfacial phosgenation of 2,2-bis(4-hydroxyphenyl)propane (bisphenol-A) with different types of PDMS oligomers including a,v-amino-organofunctional polydimethylsiloxane (AT-PDMS oligomer), a,v-hydroxy-organofunctional polydimethylsiloxane (HT-PDMS oligomer), and a,v-phenol-organofunctional polydimethylsiloxane (PT-PDMS oligomer).

In this paper, we report a new method to activate and control a piezoelectric linear motor using a switching light source through two transparent electrodes and a photoconductive coating. This coating is composed of titanium oxide phthalocyanine (TiOPc), electron transport materials, hole transport materials, and polyvinyl butyral binder. It is used to replace one of the surface electrodes of a piezoelectric serial bimorph to provide an optical interface and to construct an optopiezoelectric composite. The weight percentage of TiOPc nanoparticles, solvent compositions, and film thickness are studied to identify the optimal coating to match the electrical impedance of the piezoelectric serial bimorph in both on and off states. Experimental results show that the photoconductive coating has a good on–off ratio and low electrical impedance under conditions of high concentration of TiOPc, small film thickness, high light intensity, and low frequency. To design this motor based on a one-frequency-two-mode driving method, an analytical solution is derived and an optopiezoelectric linear motor (OP-LM) is developed. Our analytical analysis, finite element simulation, and experimental results demonstrate that traveling waves can be generated by driving this motor at a frequency between the first and the second bending modes with a 90° phase difference between two designed actuating areas. The optimal condition is to match the driving frequency and light switching frequency. The moving direction and velocity of objects in different weight can be optically controlled by illuminating different areas of an optopiezoelectric motor with two 10 W power LEDs and masks. Discussions on the developed theory, simulation, and experimental studies of the OP-LM are provided in this paper.