Concept of an artificial muscle design on polypyrrole nanofiber scaffolds

Abstract

Here we present the synthesis and characterization of two new conducting materials having a high electro-chemo-mechanical activity for possible applications as artificial muscles or soft smart actuators in biomimetic structures. Glucose-gelatin nanofiber scaffolds (CFS) were coated with polypyrrole (PPy) first by chemical polymerization followed by electrochemical polymerization doped with dodecylbenzensulfonate (DBS-) forming CFS-PPy/ DBS films, or with trifluoromethanesulfonate (CF 3 SO 3-, TF) giving CFS-PPy/TF films. The composition, electronic and ionic conductivity of the materials were determined using different techniques. The electro-chemo-mechanical characterization of the films was carried out by cyclic voltammetry and square wave potential steps in bis(trifluoromethane)sulfonimide lithium solutions of propylene carbonate (LiTFSI-PC). Linear actuation of the CFS-PPy/DBS material exhibited 20% of strain variation with a stress of 0.14 MPa, rather similar to skeletal muscles. After 1000 cycles, the creeping effect was as low as 0,2% having a good long-term stability showing a strain variation per cycle of-1.8% (after 1000 cycles). Those material properties are excellent for future technological applications as artificial muscles, batteries, smart membranes, and so on.

Conductive Polymeric-Based Electroactive Scaffolds for Tissue Engineering Applications: Current Progress and Challenges from Biomaterials and Manufacturing Perspectives

“…To compensate for the drop in conductivity for 3D scaffolds, as well as the gradual loss of conductivity over time, the doping strategy could be used to further enhance the nanofiber’s conductivity. Doping of glucose-gelatin nanofiber scaffold (CFS)/PPy with dodecylbenzenesulfonate (DBS) or trifluoromethanesulfonate (TF) was shown to be able to enhance the nanofiber scaffold’s conductivity, with TF-doped CFS/PPy showing higher conductivity (11.4 S/cm) compared to DBS-doped CFS/PPy (2.4 S/cm) [ 180 ].…”

Artificial muscle like behavior of polypyrrole polyethylene oxide independent of applied potential ranges

“…In order to get polypyrrole (PPy) based "artificial muscles" with strain and stress comparable to natural muscles (strain up to 20% and stress in range of 0.1 MPa 12 ) different designs have been checked as coiled 13 or twisted fibers 14 using conducting polymers with carbon nanotubes or PPy coated nanofiber scaffolds. 15 The most studied materials are based on PPy doped with dodecylbenzenesulfonate (DBS À ). In most experimental conditions it gives cation-driven actuators: the large DBS À anion remains immobile in the PPy network during reactions originating the entrance of cations during electrochemical reduction for charge balance, and solvents for osmotic balance 16 (break by the entrance of cations).…”

Ion Mobility in Thick and Thin Poly-3,4 Ethylenedioxythiophene Films—From EQCM to Actuation

“…For the last decade, a significant amount of research has been dedicated to conductive polymer (CP)-based actuators with bending [ 1 , 2 ] or linear [ 3 , 4 ] actuation modes (including fiber-based materials [ 5 , 6 ]) for applications in micro-actuators [ 7 ], biomedical devices [ 8 ], smart textiles [ 6 , 9 ], and more. Polypyrrole (PPy) has been a popular choice due to its typically higher strain or displacement output, as well as the possibility for electropolymerization in aqueous solutions, which presents suitability in biomedical [ 10 ] and biosensor [ 11 ] applications, among others [ 12 ].…”