Silk Fibroin Bending Actuators as an Approach Toward Natural Polymer Based Active Materials

Ander Reizabal; Daniela M Correia; Carlos M Costa; Leyre Perez-Alvarez; José L Vilas-Vilela; S Lanceros-Méndez

doi:10.1021/acsami.9b07533

Silk Fibroin Bending Actuators as an Approach Toward Natural Polymer Based Active Materials

ACS Appl Mater Interfaces. 2019 Aug 21;11(33):30197-30206. doi: 10.1021/acsami.9b07533. Epub 2019 Aug 6.

Authors

Ander Reizabal^{1

2}, Daniela M Correia^{3

4}, Carlos M Costa^{4

5}, Leyre Perez-Alvarez^{1

2}, José L Vilas-Vilela^{1

2}, S Lanceros-Méndez^{1

6}

Affiliations

¹ BCMaterials, Basque Center for Materials, Applications and Nanostructures , UPV/EHU Science Park , 48940 Leioa , Spain.
² Macromolecular Chemistry Research Group (LABQUIMAC), Department of Physical Chemistry, Faculty of Science and Technology , University of the Basque Country (UPV/EHU) , 48940 Leioa , Spain.
³ Department of Chemistry and CQ-VR , Universidade de Trás-os-Montes e Alto Douro , 5000-801 Vila Real , Portugal.
⁴ Center of Physics , University of Minho , 4710-058 Braga , Portugal.
⁵ Center of Chemist , University of Minho , 4710-058 Braga , Portugal.
⁶ Ikerbasque , Basque Foundation for Science , 48013 Bilbao , Spain.

PMID: 31330104
DOI: 10.1021/acsami.9b07533

Abstract

This work reports on the development of ionic liquid (IL)/silk fibroin (SF) composite films as electroactive polymers actuators. Different contents (20, 40, and 60% wt) of 1-butyl-3-methylimidazolium tricyanomethanide ([Bmim][C(CN₃)]) and choline dihydrogen phosphate ([Ch][DHP]) ILs were incorporated into the SF polymer matrix. Due to IL-SF interactions, morphological changes such as globule-like nanostructures are induced in the samples. High concentrations of IL promote SF β-sheet formation above 65%. Further, an increase in the thermal stability of the SF was observed through the incorporation of [Bmim][C(CN₃)]. IL type and content allow tuning of the electrical response as well as achieving bending actuation. [Bmim][C(CN3)]/SF samples allow bending responses up to 0.5 at an applied voltage of 3 V. In conclusion, this work demonstrates the ability of IL/SF composites to act as electroactive polymer actuators and opens new perspectives in the application of natural resources for smart materials.

Keywords: bending actuators; composites; ionic liquids; silk fibroin; β-sheet.