Room-temperature bonding method for polymer substrate of flexible electronics by surface activation using nano-adhesion layers

Abstract

A sealing method for polymer substrates to be used in flexible electronics is studied. For this application, a low-temperature sealing method that achieves flexible bonding of inorganic bonding material is required, but no conventional technique satisfies these requirements simultaneously. In this study, a new polymer bonding method using thin Si and Fe layers and the surface activated bonding (SAB) method are applied to bond poly(ethylene naphthalate) (PEN) films to each other. PEN films can be bonded via the proposed method without voids at room temperature, and the bonded samples are bendable. The adhesion strength of the bonded samples is so strong that fracture occurs in the polymer bulk rather than at the bond interface. Investigations of the bonded samples by transmission electron microscopy (TEM) and Fourier-transform infrared spectroscopy (FTIR) reveal that bonding is achieved by chemical interactions between the polymer surface and deposited atoms.

Integration of Heterogeneous Materials for Wearable Sensors

“…This technique mainly offers bonding of hard materials, resulting in covalent bonding [ 104 , 105 , 106 , 107 , 108 ]. In the second approach, the surfaces are simultaneously cleaned and nanoadhesion layers are deposited using a low energy Ar ion source and then brought into contact in UHV [ 109 , 110 , 111 , 112 ]. Different nanoadhesion layers such as Fe, Si, and Al have been investigated for different flexible polymers.…”

“…The adhesion can be further improved by heating the contacted surfaces at below glass transition temperatures [ 121 ]. In contrast, deposition of nanoadhesion layers causing chemical interactions between the activated surfaces can be used to increase the adhesion, as shown in Figure 5 [ 112 ]. In both cases, the influence of material type as well as plasma activation parameters on the bonding strength, is observed.…”

“…Bulk fracture in PEN near the bond interface was observed. From [ 112 ] (Copyright 2015 The Japan Society of Applied Physics).…”

Tailoring high mechanical performances of self‐healable poly(vinyl alcohol)‐based elastomers via judicious grafting of side chains

“…8,9 However, a polymer matrix may fail due to external force damage, corrosion or fatigue during operation. [10][11][12] Therefore, it is urgent to develop self-healing materials with high performances (mechanical properties and self-healing efficiency) as substrates to ensure the long-term stability of devices.…”

“…As the main materials of flexible electronic devices, 1–3 flexible polymer materials have been extensively studied due to their superior stretchability, 4, 5 light‐weight density 6, 7 and easy processability 8, 9 . However, a polymer matrix may fail due to external force damage, corrosion or fatigue during operation 10–12 . Therefore, it is urgent to develop self‐healing materials with high performances (mechanical properties and self‐healing efficiency) as substrates to ensure the long‐term stability of devices.…”