Lanthanide ions-induced formation of hierarchical and transparent polysaccharide hybrid films

Nacre-like hybrid films based on N-succinyl chitosan (NSC), sodium alginate (SA) and lanthanide ions were fabricated via coordination interactions. In this work, the binary building blocks (NSC and SA) were self-assembled into aligned hydrogel films by coordination with lanthanide ions, and hierarchical NSC-SA hybrid films were obtained upon drying. Two species of lanthanide ions (Gd3+ and Yb3+) were used to fabricate the hierarchical NSC-SA hybrid films. The as-prepared NSC-SA hybrid films exhibit high tensile strength and stability. The tensile strength and toughness of as-prepared hybrid films reach 122.10 MPa and 3.89 MJ m−3, respectively. Meanwhile, the well-aligned lamellar microstructures also exhibit a good light transmittance. The highest light transmittance reaches 92% for NSC-SA hybrid films at 760 nm. This fabrication method for hierarchical NSC-SA hybrid films is innovative due to the utilization of rare earth coordination bonding, and can serve as the basic strategy for the construction of high-performance composites in the near future.