Outstanding performance of parylene polymers as electrets for energy harvesting and high‐temperature applications

Abstract

Parylene C is used in many applications due to its high properties but it remains a material with moderate performance as long as it is intended for use as an electret. Hence, the generally accepted idea, rightly so, in the scientific and industrial community not to necessarily select parylene (i.e., parylene C) for applications where the endurance of the electret is a strong criterion. Our study provided a new perspective on the performance of parylenes as electret. In this case, we will talk about fluorinated Parylenes of the VT‐4 type and especially AF‐4 variant. Their thermal stability is outstanding and a charge stability is almost total up to 100 °C. A 50% reduction in the charge is recorded at a temperature as high as of 220 °C (9 μm thick Parylene AF‐4), making it one of the most efficient polymer electrets to date. Negatively and positively charged Parylene AF‐4 electrets presented similar performance over long durations, which is out of ordinary for the commonly employed polymeric electrets. Finally, these fluorinated polymers are therefore particularly promising new candidates for applications in electret‐based converters for energy harvesting. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020, 137, 48790.

Organic molecular and polymeric electrets toward soft electronics

“…Among the three common types of parylene (Table 1), the parylene C type has been the main focus because it is a polar material with piezoelectricity or ferroelectricity. Lagomarsini et al 31 studied the related electret properties ( e.g. effect of charge polarity, material thickness, initial charging voltage, and temperature on the surface potential decay (SPD)).…”

“…The charge density is 3.7 × 10 −3 C m −2 , which is the highest value among polymer electrets reported so far. 9,31,35,52,55…”

“…The details are described in sections 3.3 and 4.5. We compare inorganic and organic electret about represented materials, 28 surface density of the charge, 11,29 substrate, 30 charge life, 9,12,31 hardness, thickness, 29,32 processability, and applications 33 (Table 2). It is worth mentioning that inorganic electrets usually exhibit a higher σ than that of…”

Thermal Analysis of Parylene Thin Films for Barrier Layer Applications

“…The deposition process allows pinhole-free growth without inducing internal stress and possesses a high step coverage [ 2 ]. Due to the unique properties of the film, parylene is considered the material of choice for various domains, such as bio-MEMS [ 3 , 4 , 5 , 6 , 7 ], electronic insulation [ 8 , 9 ], energy harvesting [ 10 , 11 , 12 ], flow and temperature sensors [ 13 , 14 , 15 ] or medical device encapsulation [ 2 , 16 , 17 , 18 ]. Furthermore, a parylene film demonstrating excellent thermal stability is highly desirable for high-temperature environment applications, such as aerospace, automotive, battery, or high-power electronic fields.…”

Improvement in energy conversion of electrostrictive composite materials by new approach via piezoelectric effect: Modeling and experiments

“…In the past few years, the requirement of wearable electronics and wireless technologies is at the source of intensive study on electrical energy harvesting from the ambient environment. [1][2][3][4][5][6][7] This great advance in research has been brought on by new developments in low-power electronics and cordless detectors such as microelectromechanical systems (MEMS) devices. [8][9][10] There is no doubt that energy harvesting is an attractive approach for wide various self-powered microsystems.…”