Femtosecond laser micromachining of polyvinylidene fluoride (PVDF) based piezo films

Abstract

Piezoelectric polymers have been known to exist for more than 40 years, but in recent years they have been recognized as smart materials for the fabrication of microsensors, microactuators and other micro-electro-mechanical systems (MEMS). In this work, femtosecond laser micromachining of a polyvinylidene fluoride (PVDF) film, coated with NiCu on both sides, has been studied to understand selective patterning mechanisms of NiCu layers and ablation characteristics of PVDF films. A detailed characterization of morphological changes of the laser-irradiated areas has been investigated using scanning electron microscopy. Through morphological analysis, the multiple shot damage thresholds of a 28 µm thick PVDF film and 40 nm thick NiCu layer have been determined. Surface morphology examination indicates that NiCu layers are removed from the PVDF film through a sequence of cracking-peeling off-curling. In addition, the NiCu layer on the rear side was also removed by the partially transmitted laser energy. The PVDF film was removed in forms of bundles of filaments and solid fragments by a combination of pure ablation and explosive removal of material by bursting of bubbles; the role of the explosive removal becomes more dominant with the increase of laser fluence. Optimal process conditions for cutting of the PVDF film and patterning of the NiCu coating without damaging the PVDF polymer have been established and applied to fabricate a vibration microsensor prototype that shows significant potential in using PVDF-based functional microdevices for telecommunications, transportation and biomedical applications.

Reactive ion etching of poly(vinylidene fluoride-trifluoroethylene) copolymer for flexible piezoelectric devices

“…Cantilever shaped P(VDF-TrFE) actuators were also fabricated for mini-robots application, in which a multilayered P(VDF-TrFE) structure was proposed to achieve a large displacement with a low driving voltage [8]. Most of the PVDF based devices were fabricated using commercial PVDF films and traditional fabrication techniques such as scissoring, laser machining, and lamination [9,10]. With the aim of integrating piezoelectric polymers into microdevices, ionized evaporation, electrospray, electrospun, Langmuir-Blodgett deposition, and heat controlled spin coating methods were developed.…”

“…Most of the PVDF based devices were fabricated using commercial PVDF films and traditional fabrication techniques such as scissoring, laser machining, and lamination [9,10]. With the aim of integrating piezoelectric polymers into microdevices, ionized evaporation, electrospray, electrospun, Langmuir-Blodgett deposition, and heat controlled spin coating methods were developed.…”

Laser Pulses Characterization with Pyroelectric Sensors

“…The variation of the holes diameter is due to different settings during the laser process. Similar processing methods have been also explored more recently from other authors (Rabindra et al, 2008) (Lee et al, 2008). …”

An Ultrasound-Based Biomedical System for Continuous Cardiopulmonary Monitoring: A Single Sensor for Multiple Information

“…Although piezoelectric polymers offer wide range of advantages, their d 33 is low compared to ceramics. For example, polyvinylidene fluoride (PVDF) which is one of the most widely studied and used piezoelectric polymer has a d 33 of 20 to 34 pC/N [7]- [11].…”