5 years ago

Understanding the Paraelectric Double Hysteresis Loop Behavior in Mesomorphic Even-Numbered Nylons at High Temperatures

Understanding the Paraelectric Double Hysteresis Loop Behavior in Mesomorphic Even-Numbered Nylons at High Temperatures
Morton H. Litt, Zhongbo Zhang, Lei Zhu
Novel ferroelectric properties, such as slim double and single hysteresis loop (DHL and SHL) behaviors, are attractive for high energy density and low loss dielectric applications. In this study, temperature-dependent ferroelectric behavior was studied for mesomorphic even-numbered nylons (i.e., nylon-12 and nylon-6) using electric displacement–electric field (DE) loop measurements. Upon raising the temperature from room temperature to 100 °C, the DE loops became increasingly narrower, finally leading to slim DHLs with significantly enhanced apparent dielectric constants (i.e., ∼30 and ∼60) and small remanent polarizations (i.e., 3.5 and 8.2 mC/m2) for quenched and stretched nylon-12 and nylon-6, respectively. Combining wide-angle X-ray diffraction and infrared studies, changes in the mesophases and orientation of hydrogen-bonded amide groups after electric poling were used to unravel the structure–ferroelectric property relationship for the even-numbered nylons. At 100 °C, the quenched and stretched nylon-12 and nylon-6 films exhibited a paraelectric mesophase with twisted chain conformation and disordered hydrogen bonds. Upon high field poling (>100 MV/m), transient nanodomains could be generated with additional twists in the main chain. The observed DHL behavior was attributed to the electric-field-induced reversible transitions between the paraelectric (less twisted chains) and ferroelectric (more twisted chains) states in the mesomorphic crystals of even-numbered nylons. The knowledge gained from this study can inspire potential applications of n-nylons for electric energy storage, e.g., high temperature and high energy density multilayer polymer film capacitors.

Publisher URL: http://dx.doi.org/10.1021/acs.macromol.7b01137

DOI: 10.1021/acs.macromol.7b01137

You might also like
Discover & Discuss Important Research

Keeping up-to-date with research can feel impossible, with papers being published faster than you'll ever be able to read them. That's where Researcher comes in: we're simplifying discovery and making important discussions happen. With over 19,000 sources, including peer-reviewed journals, preprints, blogs, universities, podcasts and Live events across 10 research areas, you'll never miss what's important to you. It's like social media, but better. Oh, and we should mention - it's free.

  • Download from Google Play
  • Download from App Store
  • Download from AppInChina

Researcher displays publicly available abstracts and doesn’t host any full article content. If the content is open access, we will direct clicks from the abstracts to the publisher website and display the PDF copy on our platform. Clicks to view the full text will be directed to the publisher website, where only users with subscriptions or access through their institution are able to view the full article.