Study on the Preparation of Ionic Liquid Doped Chitosan/Cellulose-Based Electroactive Composites

Abstract

Electro-actuated polymer (EAP) can change its shape or volume under the action of an external electric field and shows similar behavioral characteristics with those of biological muscles, and so it has good application prospects in aerospace, bionic robots, and other fields. The properties of cellulose-based electroactive materials are similar to ionic EAP materials, although they have higher Young’s modulus and lower energy consumption. However, cellulose-based electroactive materials have a more obvious deficiency—their actuation performance is often more significantly affected by ambient humidity due to the hygroscopicity caused by the strong hydrophilic structure of cellulose itself. Compared with cellulose, chitosan has good film-forming and water retention properties, and its compatibility with cellulose is very excellent. In this study, a chitosan/cellulose composite film doped with ionic liquid, 1-ethyl-3-methylimidazolium acetate ([EMIM]Ac), was prepared by co-dissolution and regeneration process using [EMIM]Ac as the solvent. After that, a conductive polymer, poly(3,4-ethylenedioxythiophene)/poly (styrene sulfonate) (PEDOT: PSS), was deposited on the surface of the resulted composite, and then a kind of cellulose-based electroactive composites were obtained. The results showed that the end bending deformation amplitude of the resulted material was increased by 2.3 times higher than that of the pure cellulose film under the same conditions, and the maximum deformation amplitude reached 7.3 mm. The tensile strength of the chitosan/cellulose composite film was 53.68% higher than that of the cellulose film, and the Young’s modulus was increased by 72.52%. Furthermore, in comparison with the pure cellulose film, the water retention of the composite film increased and the water absorption rate decreased obviously, which meant that the resistance of the material to changes in environmental humidity was greatly improved.

A fast-response electroactive actuator based on TEMPO-oxidized cellulose nanofibers

“…In addition, weight losses of the three stages are 12%, 46%, and 12% respectively. Residual masses of TOCNF films are about 30%, which is higher than that of the regenerated cellulose film with ionic liquid in our previous work (≈17%) [30]. The higher residual masses are due to remaining ions (e.g.…”

“…With the increase of TOCNF solid content, the maximum tip displacement of the actuator firstly increases and then decreases, and the TOCNF-d/Au reaches the maximum tip displacement (32.1 mm), which shows relatively high strength and low modulus with the thickness of about 10 µm. In addition, although the TOCNF-a/Au outputs the smallest tip displacement (12.8 mm) in this work, it is still higher than the maximum tip displacement (7.3 mm) of the regenerated cellulose-based actuator (40 mm × 10 mm) in our previous work [30] and most of the results in table 1. This should be related not only to the multilayer structure of TOCNF film with loose and dense parts but also to the high electrical conductivity and uniform atomic deposition of Au.…”

“…Crystallization and structure determination were performed by x-ray diffraction; thermogravimetric analysis (TGA) was performed by a synchronous thermal analyzer (TG 209 F1 Libra, NETZSCH, Selb, Bavaria, Germany); the surface morphology and cross-section of the film were determined by scanning electron microscope (SEM, Zeiss, Oberkochen, Germany); the tensile strength and Young's modulus of the film were tested with electronic universal material testing machine (INSTRON 5565, Boston, Massachusetts, MA, USA). The details of these experiments were shown in our previous study [30].…”

“…The size of the actuator was 40 mm × 10 mm, and the actuator was clamped about a 5 mm × 10 mm area at one end. To evaluate the actuation behavior, the testing device was built as in previous work [30]. The function signal generator and power amplifier were used as the source of the excitation electric field.…”