A solid hydraulically amplified piezoelectric microvalve

Abstract

We report a piezoelectrically driven and hydraulically amplified axial polymer microvalve. The microvalve is normally open and is assembled primarily with stereolithographically fabricated polymer components. An incompressible elastomer is used as a solid hydraulic medium to convert the small axial displacement of a piezoelectric actuator into a large valve head stroke while maintaining a large blocking force. Also, the axial design of the microvalve enables densely packed valve arrays. One application of this microvalve is in pneumatic tactile displays, which operates against gas pressure up to approximately 90 kPa and switching speed between 1 and 200 Hz. The current valve design has a maximum static hydraulic amplification ratio of 5 at 30 V driving voltage and a maximum valve head stroke of 37 μm at 150 V. Under a 94.4 kPa differential pressure, the flow rate of the valve and the closing voltage measure are 785 mL min −1 and 150 V, respectively. The function of the microvalve as an on-off switch for a pneumatic microbubble tactile actuator is demonstrated.

Adhesion and Mechanical Properties of PDMS-Based Materials Probed with AFM: A Review

“…Recent microfluidic and micro electro mechanical systems (MEMS) have demonstrated that the high elasticity (flexibility) of PDMS offers unique advantages over more traditional rigid substrate materials such as glass, silicon and harder polymers [11]. Examples include micropumps employing elastomeric displacement amplification [44], PDMS micro valves operated using solid hydraulics [45], flexible micropillar arrays for biological force measurements [46], mechanically adjustable PDMS devices for cell trapping [47] and flexible adaptable fluid lenses [48]. However, low hardness prevents many potential applications of PDMS, for instance in some chemical and high pressure fields [49].…”

A normally-closed piezoelectric micro-valve with flexible stopper

“…Chen et al AIP Advances 6, 045112 (2016) and his team 18 presented that a solid hydraulically amplified piezoelectric micro-valve with an incompressible gelatin elastomer as hydraulic medium, because it was using semisolid medium, the amplification and working frequency got constraints. More important, all of the hydraulically amplified piezoelectric micro-valves in Ref.…”

An Electromagnetic Microvalve for Pneumatic Control of Microfluidic Systems

“…In this article, a simple polymer-based solid-hydraulic amplification (SHA) theory 19,20 is used to minimize the displacement of the valve core. Figure 2 shows the principle of the SHA mechanism.…”

“…As Wu et al 19 demonstrated, there are two assumptions upon which the SHA concept is based: the negligible volume change of the gas chamber (volume of microchannel) and the zero-volume change of incompressible material under small deformations. In this article, there is no special SHA media or special volume for the designed microvalve; instead, the middle PDMS membrane and air microchannel act as these components separately.…”