title: Smart conducting polymer composites having zero temperature coefficient of resistance.
abstract: Zero temperature coefficient of resistance (TCR) is essential for the precise control of temperature in heating element and sensor applications. Many studies have focused on developing zero-TCR systems with inorganic compounds; however, very few have dealt with developing zero-TCR systems with polymeric materials. Composite systems with a polymer matrix and a conducting filler show either a negative (NTC) or a positive temperature coefficient (PTC) of resistance, depending on several factors, e.g., the polymer nature and the filler shape. In this study, we developed a hybrid conducting zero-TCR composite having self-heating properties for thermal stability and reliable temperature control. The bi-layer composites consisted of a carbon nanotube (CNT)-based layer having an NTC of resistance and a carbon black (CB)-based layer having a PTC of resistance which was in direct contact with electrodes to stabilize the electrical resistance change during electric Joule heating. The composite showed nearly constant resistance values with less than 2% deviation of the normalized resistance until 200 °C. The CB layer worked both as a buffer and as a distributor layer against the current flow from an applied voltage. This behavior, which was confirmed both experimentally and theoretically, has been rarely reported for polymer-based composite systems.
authors.affiliation: Samsung Advanced Institute of Technology, Suwon, 443-803, Korea. leo.park@samsung.com.
authors.forename: Kunmo
authors.initials: K
authors.lastname: Chu
authors.forename: Sung-Chul
authors.initials: SC
authors.lastname: Lee
authors.forename: Sangeui
authors.initials: S
authors.lastname: Lee
authors.forename: Dongearn
authors.initials: D
authors.lastname: Kim
authors.forename: Changyoul
authors.initials: C
authors.lastname: Moon
authors.forename: Sung-Hoon
authors.initials: SH
authors.lastname: Park