title: Modifying Mechanical, Optical Properties and Thermal Processability of Iridescent Cellulose Nanocrystal Films Using Ionic Liquid.
abstract: Iridescent films formed from the self-assembly of cellulose nanocrystals (CNCs) are brittle and difficult to handle or integrate within an industrial process. Here we present a simple approach to prepare iridescent CNC films with tunable pliability and coloration through the addition of ionic liquids (ILs) of 1-allyl-3-methylimidazolium chloride (AmimCl) as plasticizers. By using the undried CNC film as a filter membrane and ILs solution as a leaching liquid, it was found that the filtration process made ILs uniformly interpenetrate into CNC film due to the strong ionic interaction between CNC and AmimCl. Unexpectedly, the filtration process also gave rise to partial desulfurization of CNC film, which is conducive to the improvement of thermal stability. Benefiting from the improved thermal stability and the dissolving capacity of AmimCl for cellulose at high temperature, the incorporated ILs enable the cholesteric CNC film to be further toughened via a hot-pressing treatment. This study demonstrates that ionic liquids have great potential to modify the mechanical, optical properties as well as the thermal stability of iridescent CNC films.
authors.affiliation: Key Laboratory of Rubber-Plastics, Ministry of Education/Shandong Provincial Key Laboratory of Rubber-Plastics, Qingdao University of Science & Technology , Qingdao 266042, China.
authors.forename: Ping
authors.initials: P
authors.lastname: Liu
authors.affiliation: Key Laboratory of Rubber-Plastics, Ministry of Education/Shandong Provincial Key Laboratory of Rubber-Plastics, Qingdao University of Science & Technology , Qingdao 266042, China.
authors.forename: Xin
authors.initials: X
authors.lastname: Guo
authors.affiliation: Key Laboratory of Rubber-Plastics, Ministry of Education/Shandong Provincial Key Laboratory of Rubber-Plastics, Qingdao University of Science & Technology , Qingdao 266042, China.
authors.forename: Fuchun
authors.initials: F
authors.lastname: Nan
authors.affiliation: Key Laboratory of Rubber-Plastics, Ministry of Education/Shandong Provincial Key Laboratory of Rubber-Plastics, Qingdao University of Science & Technology , Qingdao 266042, China.
authors.forename: Yongxin
authors.initials: Y
authors.lastname: Duan
authors.affiliation: Key Laboratory of Rubber-Plastics, Ministry of Education/Shandong Provincial Key Laboratory of Rubber-Plastics, Qingdao University of Science & Technology , Qingdao 266042, China.
authors.forename: Jianming
authors.identifier: http://orcid.org/0000-0002-0252-4516
authors.initials: J
authors.lastname: Zhang
keywords: cellulose nanocrystal; hot-pressing; ionic liquid; plasticization; structural color