ABSTRACT
This entry aims to reveal the importance of the effects of electrets as biomaterials in the field of biophysical phenomena and hence biomedical applications. The methods of electret formation are reported, which include different methods of charging such as contact electrification; thermal method; corona charging; liquid contact; and irradiation by gamma rays, beta rays, X-rays, and light. The method of investigating charge storage and charge decay by thermally stimulated depolarization current (TSDC) is also discussed in detail. Literature survey of studies by different authors is summarized to examine the choice of materials as bioelectrets and their biomedical applications. The work by different authors on collagen of bones and blood vessels is mentioned, so that a conclusion may be drawn for the choice of compatible biomaterials used in artificial heart vessels and artificial bone devices. This entry also covers the topic of plasma processing on polymers as well as the study on fibrous polystyrene (PS), polyhydroxyethylmethacrylate (PHEMA), polyetheretherketone (PEEK), polyethyleneterephthalate (PET), and polyethylenenaphthalate (PEN). Keratin and bile acid are used for preparation of biomaterials. The dielectric measurements and piezoelectricity of anionic and native collagens are reported and the results are utilized for cardiovascular prostheses, cellular growth, and systems to control drug delivery. Moreover, studies aimed at understanding the microscopic structure of life along with awareness of macroscopic effects through programming are reported. The most recent advancement reported in this entry is the utilization of nanotechnology in the field of bioelectrets. It has been concluded that when carbon nanotubes are introduced into a polymer matrix, there is an increase in electrical conductivity, optical character, and mechanical strength.
