Robust and Mechanically and Electrically Self-Healing Hydrogel for Efficient Electromagnetic Interference Shielding

Abstract

Autonomously self-healing hydrogels have received considerable attentions due to their capacity for repairing themselves spontaneously after suffering damage, which can provide a better stability and a longer life span. In this work, a robust and mechanically and electrically self-healing hydrogel with an efficient electromagnetic interference (EMI) shielding performance was successfully fabricated via the incorporation of multiwalled carbon nanotubes (MWCNTs) into the hydrophobically associated polyacrylamide (PAM) hydrogels by using cellulose nanofiber (CNF) as the dispersant. It was been found that CNF could not only assist the homogeneous dispersion of MWCNTs but also effectively enhance the mechanical property of the resultant hydrogels. As a result, the optimal tensile strength (≈0.24 MPa), electrical conductivity (≈0.85 S m), and EMI shielding effectiveness (≈28.5 dB) were achieved for the PAM/CNF/MWCNT composite hydrogels with 1 wt % MWCNTs and 0.3 wt % CNF, which showed 458, 844, and 90% increase over (≈0.043 MPa, ≈0.09 S m, and ≈15 dB, respectively) the PAM hydrogel. More encouragingly, these composite hydrogels could rapidly restore their electrical conductivity and EMI shielding effectiveness after mechanical damage at room temperature without any external stimulus. With outstanding mechanical and self-healing properties, the prepared composite hydrogels were similar to human skin, but beyond human skin owing to their additional satisfactory electrical and EMI shielding performances. They may offer promising and broad prospects in the field of simulate skin and protection of precision electronics.

Poly(vinyl alcohol)–Carbon Nanodots Fluorescent Hydrogel with Superior Mechanical Properties and Sensitive to Detection of Iron(III) Ions

“…The pure PVA hydrogels formed by entanglement of PVA chains, presenting disordered pores . Displaying hydrogels with various sizes of pore structures in SEM images implied that the network structure formed by the cross‐linking of PVA and CNDs was more uniform and smaller, so that the hydrogel had excellent mechanical properties . Besides, PVA‐CNDs hydrogels exhibited interconnected and relatively ordered porous network structures.…”

“…The tensile stress test was carried out using a cylindrical hydrogel sample (length 50 mm ( l ), width 4 mm ( r )), and the tensile rate was fixed at 50 mm min −1 . The cylindrical hydrogel samples (length 20 mm ( l ), width 14 mm ( r )) were subjected to compression test with speed of 2 mm −1 . In this experiment, the nominal tensile stress (σ) and the nominal tensile strain (ε) were determined from the fracture point of the stress–strain curve .…”

Nanoparticle–Polymer Synergies in Nanocomposite Hydrogels: From Design to Application

“…Because the chemical functionalization disrupts the electronic structure of pristine carbon nanomaterials, which reduces the conductivity of composite gels, physical approaches, such as polymer wrapping and cellulose‐assisted dispersion, have been developed. Polymer wrapping, a common technique that facilitates the transfer of carbon nanomaterials to the aqueous phase, involves the utilization of polymers containing aromatic groups, such as polystyrenesulfonate, which can wrap around carbon materials through π–π stacking and hydrophobic–hydrophilic interactions.…”

“…b) CNT dispersion with incorporated CNF: i) photographs of the CNF dispersion; ii) CNT dispersion without CNF, and iii) CNT/CNF (wt% = 10:3) dispersion; iv) photographs of PAAm/(CNT–CNF) NC gel showing excellent mechanical properties: knotting and stretching with a knot. Reproduced with permission . Copyright 2018, American Chemical Society.…”

“…Taking advantage of this behavior, Fu et al. fabricated a poly(acrylamide) (PAAm) NC gel using cellulose nanofiber (CNF) as a CNT dispersion agent, and the as‐prepared hydrogel exhibited excellent mechanical properties (Figure b) and electrical performance due to the ideal dispersion of CNTs …”