Preparation And Bionic Functional Research Of Cellulose Based Nanocomposite

As a kind of natural renewable resource,agricultural waste tobacco has been widely concerned.It is of great significance to utilize the tobacco straw with high important value.Recently,flexible actuators,which can respond to various environmental stimulus,have attracted great attention.In this work,a bio-inspired Janus film consisting of two layers was well designed and fabricated via a simple method.Briefly,the lignin-containing cellulose nanofibrils(CNF)were prepared through a one-step formic acid hydrolysis and the followed homogenization,directly from tobacco stalk.The CNF/ graphene oxide(GO)bilayer film was fabricated by a simple two-step filtration.The sticky lignin on CNP strongly adhered to GO layer to make the obtained bilayer film very stable,particularly in water.Then,the CNF/GO bilayer film was reduced in an ascorbic acid solution.After reduction and drying,the final Janus(CNP/rGO)film was obtained.The obtained Janus film can be used as a flexible actuator,which can be operated based on water absorption and dehydration of CNP and conductivity and light-to-heat conversion characteristics of rGO.Different from the traditional bilayer designs,lignin was acted as a biological adhesive between CNP layer and rGO layer,which was inspired by the internal structure of natural lignocellulose(just like lignin existing among cellulosic fibers).Results showed the Janus film has good water resistance and its tensile strength is 141.2 MPa.Due to the different water absorption rate of CNP layer and rGO layer,the composite has high humidity,near-infrared radiation and electrical stimulation response.Under the light stimulation of NIR with low energy density,the maximum bending angle of CNP / rGO actuator is 70 °.At 10 V,the maximum bending angle of CNP / rGO film is 270 °,the response speed is 15 ° / s,and it has good cycle stability(500 times).The electromagnetic shielding effectiveness of the obtain Janus film containing 50% rGO was about 45 dB,which was higher than the commercial standard of 20 d B.Therefore,this CNP-based Janus film can be potentially used in many fields such as humidity sensor,bionic artificial arm/driving motor.This work is helpful to develop facile and environmentally friendly strategies for the construction of multi-responsive Janus actuator/intelligent devices.