Uniformly assembly of filamentous phage/SiO2 composite films with tunable chiral nematic structures in capillary confinement

Abstract

The design and development of biomimetic advanced materials can generate exquisite microstructures and excellent performance. Using the liquid crystal assembly of biomacromolecules can effectively realize architectures control at micro-/nanoscale. Filamentous M13 phage has attracted extensive attention due to its good monodispersity and high aspect ratio, which makes it the ideal building block to assembly liquid crystal-like structures. Millimeter-sized M13 film with the thickness of 300 μm (ChM13) is assembled in a capillary. Anisotropic evaporation and the drying process in the capillary confinement promote the formation of uniform chiral nematic structures. The formation process and microstructure of the resulting film are characterized in detail. Furthermore, the microstructures and mechanical properties of the film are tunable by incorporating inorganic silica component with various contents to form similar composite structures found in structurally colored leaves. As the silica content increases, the half helical pitch of the chiral nematic structure decreases from 14.5 to 5.5 μm and recovers to 8 μm. The Young' s modulus increases from 492 to 920 MPa, and the hardness increases from 6.2 to 20.6 MPa. This preparation strategy is expected to provide new insight and ideas into formation of elaborate biological structures under mild conditions.