| Biological tissue provides many inspirations for the design and preparation of high-performance materials,especially the design and preparation of high-performance polymer materials.The design of biomimetic polymer was mainly based on the bio-inspired structure and performance of organism,to prepare functional polymers with similar biological structure and performance.In this paper,high strength nacre-like polymer films and self-healing polymer hydrogel were fabricated by organic metal ion coordination.The specific content is divided into four parts:Firstly,sodium alginate and carboxyl functional chitosan（N-chitosan）were chose to prepare high-performance nacre-like polymer films through metal ion（lanthanide ions）coordination crosslinking.A series of natural polymer-metal ions hydrogel were prepared by lanthanide ions coordination.Subsequently,the natural polymer-lanthanide ions films with hierarchical structure was obtained by evaporation drying.Through the study of structure and mechanical properties,it is proved that the prepared nacre-like polymer films not only possess the layered structure,but also exhibit high mechanical strength and stability.Furthermore,we analyzed the formation mechanism of layered structure,and develop a new method（Gel-Drying）for the preparation of high-performance nacre-like polymer films.Secondly,through the metal ions coordination crosslinking and Gel-Drying method,a series of graphene oxide enhanced nacre-like sodium alginate/graphene oxide nanocomposite film and xanthan gum/graphene oxide nanoconposite film were fabricated.On the one hand,the introduction of graphene oxide nanosheets improves the regularity of nano-layers.On the other hand,it greatly improves the mechanical properties of the nanocomposite films.Furthermore,due to the excellent thermal conductivity of graphene,the prepared sodium alginate/graphene oxide and xanthan gum/graphene nanocomposite film showed excellent thermal conductivity.Due to the specificity of natural polysaccharide chains,the as-prepared polymer nanocomposite films exhibited shape-memory property.Compared with the traditional method for the preparation of nacre-like films,the metal ion coordination endows the as-prepared nacre-like films with high stability.Thirdly,bio-inspired by the self-healing property of organism,self-healing polymer hydrogels with excellent mechanical properties and completely self-healing properties were prepared by metal ion coordination crosslinking.The fabrication and design of self-healing hydrogels were mainly based on the dynamic metal ions coordination and double network structure.One of the network was formed through ligand molecules extended polyethylene glycol（PEG）chains by metal ions coordination crosslinking,another network was formed through the carboxyl groups on the polyacrylic acid by metal ion coordination crosslinking.We used pyridine ligand to expand the PEG molecular chain,and successfully prepare an extended PEG chains with abundant ligand units.Then,high-performance double network self-healing hydrogel（PEG/PAA）was prepared through radical polymerization.The as-prepared double network self-healing hydrogel exhibited high mechanical properties（tensile strength,0.4 MPa and elongation,1560%）and completely self-healing property within 12 h at room temperature.In addition,the as-prepard PEG/PAA hydrogel also exhibited a certain conductivity(0.042 S cm-1)and tensile sensitivity.In the end,we designed the expanded PEG chains by the reaction of epoxy functionalized PEG chain with glycine molecule,and successfully prepared an expanded PEG chains with abundant carboxyl groups.And then,double network self-healing PEG/PAMAA was prepared through radical polymerization.The as-preaprd PEG/PAMAA hydrogel also exhibits excellent mechanical strength and self-healing properties,and also shows certain electrical conductivity and mechanical sensitivity.Therefore,the self-healing hydrogels have a widely potential applications,including biosensors,wearable electronic devices and intelligent robot. |
