Skin Collagen Fiber-Biotemplated Synthesis of Size-Tunable Silver Nanoparticle-Embedded Hierarchical Intertextures with Lightweight and Highly Efficient Microwave Absorption Properties

The bioinspired approach to the construction of well-ordered microstructures is a crucial intersection of the branches of materials science and biotechnology. In this study, size-tunable silver nanoparticles (Ag NPs) have been successfully prepared on a skin collagen fiber (SCF) biotemplate, which shows a hierarchical interwoven structure in nature having novel, special, and highly compact interlaced, biosupported Ag NPs chains. Conductivity measurements indicate that these novel Ag NPs/SCF@BT composites are semiconductive and have a typical percolation threshold of 0.85% (w/w) silver fraction. The enhancement of dielectric loss properties of Ag NPs/SCF@BT can be expressed by the Debye dipolar polarization model with three kinds of coexistent dielectric polarizations, in which the unique multiple reflection and scattering absorption characteristics are due to the special natural mesostructure of the SCF biosupport. Subsequently, it was found that the reflection loss (RL) values of the Ag NPs/SCF@BT0.35 composite can be achieved in the whole X-band (exceeding -10 dB), the C-band, and some part of the S-band (exceeding 5 dB) with thicknesses from 2.0 to 5.0 mm. An important feature of the present work is that the specific gravity of our Ag NPs/SCF@BT composite is only 1/10 that of inorganic absorbing materials because of the special construction of this novel composite from biological tissue. Based on the promising properties of these biohybirds, the present work will hopefully lead to the development of new, lightweight, low-cost, flexible, and highly efficient microwave absorption materials based on biologic SCF-derived composites.