MWCNTs reinforced conductive, self‐healing polyvinyl alcohol/carboxymethyl chitosan/oxidized sodium alginate hydrogel as the strain sensor

Abstract

The preparation and application of hydrogel has been a hot research field in recent years. Here in, a composite hydrogel based on poly(vinyl alcohol) (PVA), carboxymethyl chitosan (CMCS), oxidized sodium alginate (OSA), and oxidized multiwall carbon nanotubes (OMWCNTs) was successfully prepared. Hydrogen and imine bonds of the hydrogel endowed the composite hydrogel with selfhealing property and pH sensitivity. The fracture strength of the hydrogel was enhanced to about 0.8 MPa with the help of OMWCNTs, which was about 2.5 times compared with the one without OMWCNTs. Meanwhile, a new conductive network inside the hydrogel was constructed by OMWCNTs, which improved the conductivity of the hydrogel from 1.75 × 10 −4 to 7.02 × 10 −4 S/cm. The sensing test of the hydrogel showed that it could produce profound feedback signals for the deformation caused by external force and response to human body movements, such as finger bending, swallowing, and speaking.

Electrically Conductive and 3D‐Printable Oxidized Alginate‐Gelatin Polypyrrole:PSS Hydrogels for Tissue Engineering

“…[ 92 ] By this particle‐composite approach, a higher MWCNT content resulted in increased hydrogel stiffness as well as strain‐dependent electrical conduction due to increased particle percolation upon deformation. [ 92 ] The combination of oxidized alginate with chitosan provided self‐healing properties to the hydrogels via Schiff base formation. [ 92 ] Closest to the material combination in the present study, PPy containing oxidized alginate‐gelatin hydrogels via in situ polymerization have been suggested for mechanical sensor applications.…”

“…[ 92 ] The combination of oxidized alginate with chitosan provided self‐healing properties to the hydrogels via Schiff base formation. [ 92 ] Closest to the material combination in the present study, PPy containing oxidized alginate‐gelatin hydrogels via in situ polymerization have been suggested for mechanical sensor applications. [ 57 ] Besides the difference in application, the authors combined ethylenediamine‐modified gelatin, oxidized alginate, Py, and oxidizer in one reaction step in situ .…”

“…Electroactive oxidized-alginate based hydrogels have been recently explored for sensor applications. [57,92] Oxidized-alginate carboxymethyl-chitosan hydrogels have been reinforced by multiwalled carbon nanotubes (MWCNT) to form electrically conductive and self-healing strain sensors. [92] By this particle-composite approach, a higher MWCNT content resulted in increased hydrogel stiffness as well as strain-dependent electrical conduction due to increased particle percolation upon deformation.…”

“…[57,92] Oxidized-alginate carboxymethyl-chitosan hydrogels have been reinforced by multiwalled carbon nanotubes (MWCNT) to form electrically conductive and self-healing strain sensors. [92] By this particle-composite approach, a higher MWCNT content resulted in increased hydrogel stiffness as well as strain-dependent electrical conduction due to increased particle percolation upon deformation. [92] The combination of oxidized alginate with chitosan provided self-healing properties to the hydrogels via Schiff base formation.…”

Highly Efficient Adsorption of Heavy Metals and Cationic Dyes by Smart Functionalized Sodium Alginate Hydrogels

“…SA (5 g) was dispersed in anhydrous ethanol (50 mL) for 2 h, and 40 mL aqueous solution (2.5 g, NaIO 4 ) was dropped into SA-ethanol dispersion in the dark for 12 h (318.15 K, pH = 4.0). Furthermore, ethylene glycol (5 mL) was used to terminate reaction, the product was washed 3 times with a mixture of ethanol and water (v/v = 5:4), and finally, DSA was vacuum-dried [ 47 ]. Using an automatic potentiometric titrator and the hydroxylamine hydrochloride method, the oxidation degree (OD) of DSA was determined by potentiometric titration for the detection of aldehyde groups [ 22 , 37 ], and the OD of DSA is 64.28%.…”