title: Towards practical application of paper based printed circuits: capillarity effectively enhances conductivity of the thermoplastic electrically conductive adhesives.
abstract: Direct printing nanoparticle-based conductive inks onto paper substrates has encountered difficulties e.g. the nanoparticles are prone to penetrate into the pores of the paper and become partially segmented, and the necessary low-temperature-sintering process is harmful to the dimension-stability of paper. Here we prototyped the paper-based circuit substrate in combination with printed thermoplastic electrically conductive adhesives (ECA), which takes the advantage of the capillarity of paper and thus both the conductivity and mechanical robustness of the printed circuits were drastically improved without sintering process. For instance, the electrical resistivity of the ECA specimen on a pulp paper (6 × 10(-5)Ω · cm, with 50 wt% loading of Ag) was only 14% of that on PET film than that on PET film. This improvement has been found directly related to the sizing degree of paper, in agreement with the effective medium approximation simulation results in this work. The thermoplastic nature also enables excellent mechanical strength of the printed ECA to resist repeated folding. Considering the generality of the process and the wide acceptance of ECA technique in the modern electronic packages, this method may find vast applications in e.g. circuit boards, capacitive touch pads, and radio frequency identification antennas, which have been prototyped in the manuscript.
authors.affiliation: Division of Energy and Environments, Graduate School at Shenzhen, Tsinghua University, Xili University Town, Shenzhen City, China.
authors.forename: Haoyi
authors.initials: H
authors.lastname: Wu
authors.affiliation: Division of Energy and Environments, Graduate School at Shenzhen, Tsinghua University, Xili University Town, Shenzhen City, China.
authors.forename: Sum Wai
authors.initials: SW
authors.lastname: Chiang
authors.affiliation: 1] School of Materials Science and Engineering, Georgia Institute of Technology, 771 Ferst Drive, Atlanta, GA, 30332, USA [2].
authors.forename: Wei
authors.initials: W
authors.lastname: Lin
authors.affiliation: Division of Energy and Environments, Graduate School at Shenzhen, Tsinghua University, Xili University Town, Shenzhen City, China.
authors.forename: Cheng
authors.initials: C
authors.lastname: Yang
authors.affiliation: School of Materials Science and Engineering, Georgia Institute of Technology, 771 Ferst Drive, Atlanta, GA, 30332, USA.
authors.forename: Zhuo
authors.initials: Z
authors.lastname: Li
authors.affiliation: Division of Energy and Environments, Graduate School at Shenzhen, Tsinghua University, Xili University Town, Shenzhen City, China.
authors.forename: Jingping
authors.initials: J
authors.lastname: Liu
authors.affiliation: Division of Energy and Environments, Graduate School at Shenzhen, Tsinghua University, Xili University Town, Shenzhen City, China.
authors.forename: Xiaoya
authors.initials: X
authors.lastname: Cui
authors.affiliation: Division of Energy and Environments, Graduate School at Shenzhen, Tsinghua University, Xili University Town, Shenzhen City, China.
authors.forename: Feiyu
authors.initials: F
authors.lastname: Kang
authors.affiliation: 1] School of Materials Science and Engineering, Georgia Institute of Technology, 771 Ferst Drive, Atlanta, GA, 30332, USA [2] Department of Electronic Engineering, Chinese University of Hong Kong, Shatin, NT, Hong Kong SAR, China.
authors.forename: Ching Ping
authors.initials: CP
authors.lastname: Wong