Biomimetic Mechanically Enhanced Carbon Nanotube Fibers by Silk Fibroin Infiltration

Abstract

Natural materials, such as silk, nacre, and bone, possess superior mechanical properties which are derived from their unique hierarchical structures. Individual carbon nanotubes (CNTs) are considered as one of the strongest materials. However, macroscopic CNT fibers usually have breaking strength far below that of individual CNTs. In this work, by mimicking the structure of natural silk fibers, strong and stiff CNT fibers are prepared by infiltrating silk fibroin (SF) into CNT fibers. There are abundant hydrogen bonds in SF, contributing to the enhanced interactions between neighboring CNTs. Glycerol is selected to promote the formation of β‐sheet conformation in SF, leading to further enhanced strength and modulus. Remarkably, the SF infiltrated CNT fibers show breaking strength of 1023 MPa, toughness of 10.3 MJ m−3, and Young's modulus of 81.3 GPa, which are 250%, 132%, and 442% of the pristine CNT fibers. The structure of the SF and the interactions between CNTs and SF are studied via Fourier transformed infrared spectroscopy and molecular dynamics simulation. Mimicking the hierarchical structures of natural silk fibers and enhance the interfacial load transfer by infiltrating SF are effective for reinforcing CNT fibers, which may be useful in the design and preparation of other structural materials.

Fast Large‐Stroke Sheath‐Driven Electrothermal Artificial Muscles with High Power Densities

“…[17][18][19][20][21] CNT yarns are especially promising candidates due to their high strokes, electrical conductivity, thermal conductivity, and mechanical strength. [22,23] When This angle decreases to zero in going from yarn surface to yarn center, which means that the material near yarn center consumes energy without making much contribution to muscle stroke. [24,26] The weight of needed CNTs can be reduced by fabricating sheath-run muscles (SRAMs), [30] which deploy a twisted CNT yarn as the core and a polymer guest as the sheath.…”

Bioinspired carbon nanotube-based materials

“…4b), showing increased breaking strength up to 1023 MPa (+ 250%), improved toughness from 7.8 to 10.3 MJ m -3 (+ 132%), and Young's modulus of 81.3 GPa (+ 442%). 94 MD simulation indicated that the glycerol-accessional -sheet of SF along with abundant hydrogen bonds between SF and CNTs contributed to enhancing the mechanical property of the CNTs fibers. To construct the assembled CNTs yarns with higher mechanical property, inspired by the mechanical exercising-induced hierarchical structure of human muscle, through cyclic stretching training (cyclic stretching or cyclic loading), Xu et al firstly created a novel microstructure-reorganized strategy to fabricate a hierarchical CNTs bundle and CNTs thread mechanical organizing structure (Fig.…”

“…Reproduced with permission. 94 Copyright 2021, Wiley-VCH. (c) Bioinspired microstructurereorganized behavior of CNT yarn.…”

Immune Response to Silk Sericin–Fibroin Composites: Potential Immunogenic Elements and Alternatives for Immunomodulation

“…[16,42] The structure of the protein determines its physical and biological properties, in that the 𝛽-sheet crystalline regions of SF give it good mechanical properties (Figure 1) while the hydrophilic regions makes it elastic. [9,12,39,43] The biopolymer SS, acting as a glue-like protein in the cocoon, is composed of 18 amino acids [20] and has a molecular weight that can vary between 10 and 350 kDa. [28] Serine, a hydrophilic amino acid, represents one third of the total composition of SS.…”