Reinforcement of Piezoelectric Polymers with Carbon Nanotubes: Pathway to Next-generation Sensors

Abstract

Piezoelectric polymers such as poly(vinylidene fluoride) (PVDF) are being currently utilized as low-cost sensors in many structural vibration control applications and measurements. Their low electromechanical coupling coefficient, however, has always been a concern when utilized in different applications. In order to remedy this, carbon nanotubes, known for their extraordinary properties, can be mixed with such piezoelectric polymers as they have the potential to improve the electromechanical response of these polymers. Along this line of reasoning, different types of nanotubes; namely, single-walled and multiwalled are blended with a copolymer of PVDF. Through extensive experimental vibration testing and theoretical verification, it is found that the nanotube-based polymers yield better response characteristics than those of the plain piezoelectric polymers. More specifically, it is demonstrated that the dominant mechanism responsible for improved sensing performance is the increased Young’s modulus of elasticity of the nanotube-based polymer for the samples considered here. The significant change in properties of these piezoelectric polymers with different fabrication conditions and nanotube addition, though provokes doubts about standardization, creates a pathway for the development of next-generation sensors with enhanced or entirely new properties.

Enhanced piezoelectric performance from carbon fluoropolymer nanocomposites

“…For many growing, high-value applications, compliant materials with lower mechanical impedance, cost, and driving voltages are required. 8 The discovery of piezoelectricity in semicrystalline polyvinylidene fluoride (PVDF) by Kawai in 1969 introduced a new highly flexible and processable material. 9 The alternating repeat unit (CH 2 -CF 2 ) allows for two dominant crystalline phases, referred to as a and b.…”

Technology Survey for Enhancement of Chemical Biological Radiological and Nuclear Respiratory Protection

“…They are most widely used due to their fast electromechanical response and high generative forces (Harrison and Ounaies, 2001). However, electric EAPs require higher voltages than ionic EAPs which can make them unsafe in many applications (Ramaratnam and Jalili, 2006). Thin films of dielectric material are used to reduce the required voltage.…”

“…Ionic EAPs are advantageous because of their low voltage; they have large displacements, but tend to respond slower than electric EAPs as they are diffusion rate limiting. In addition, the need to keep the polymer or gel wet has limited the commercial application of ionic EAPs (Ramaratnam and Jalili, 2006). Flexible coatings are being developed for ionic polymer metal composites to remove this limitation.…”

Buckling of boron nitride nanotube reinforced piezoelectric polymeric composites subject to combined electro-thermo-mechanical loadings

“…Numerous studies have shown that CNTs possess extraordinary mechanical properties such as high stiffness to weight and strength to weight ratios, and enormous electrical and thermal conductivities [1][2][3][4][5][6][7][8]. However, their applications are limited in high strength and uniform electronic structures.…”