# Durable Metallized Liquid Crystal Polymer Fibers Enable Flexible and Tough Electrical Heaters

## TL;DR

Researchers created durable, flexible electrical heater fibers using copper-coated liquid crystal polymer, suitable for wearable electronics and medical applications.

## Contribution

A novel metallized fiber design with high strength, flexibility, and durability for efficient Joule heating in wearable systems.

## Key findings

- The fibers exhibit a high temperature threshold of up to 200 °C and immense strength of 2.94 GPa.
- They show low electrical resistance (5.51 Ω/cm) and ultrafast heating response (12.6 °C·s−1) at low voltages.
- The fibers maintain stable resistance after repeated bending, folding, and washing (50 cycles).

## Abstract

Fiber-shaped electrical heaters with high flexibility and excellent adaptability make an ideal candidate for the application of wearable electronics but still suffer from low strength and poor durability. Herein, an all-in-one Joule-heating fiber capable of outstanding mechanical properties, good heating efficiency, and long-term stability is reported by using polymer-assisted metal deposition to firmly coat Cu nanoparticles on high-performance liquid crystal polymer (LCP) fibers. Taking advantage of LCP, the resultant fibers exhibit a satisfying temperature threshold (up to 200 °C) and immense strength (2.94 GPa). By virtue of dense and continuous Cu film, these fibers show low electrical resistance (5.51 Ω/cm) and an ultrafast response rate (12.6 °C·s−1) at low supplied voltages (0.5–3.5 V). Benefiting from the levodopa/polyethyleneimine interface design, such fibers maintain nearly constant resistance after repeatable bending, folding, and even washing (50 cycles). Based on the above-mentioned merits, a wearable patch with a Joule-heating function is knitted by using as-made fibers to offer therapeutic benefits for human body joints. This work demonstrates prospective potential for enriching the challenging applications of fiber-shaped electrical heating systems.