Transparent and Flexible Nacre‐Like Hybrid Films of Aminoclays and Carboxylated Cellulose Nanofibrils

Abstract

Nacre and other biological composites are important inspirations for the design and fabrication of multifunctional composite materials. Transparent, strong, and flexible hybrid films of aminoclays (AC) and carboxylated cellulose nanofibrils (CNF) with a nacre-like microstructure at AC contents up to 60 wt% are prepared. The high transmittance of visible light is attributed to the high homogeneity of the hybrid films and to the relatively small refractive index contrast between the CNF-based matrix and synthetic AC. The strength and strain to failure of the hybrids are significantly higher than biogenic nacre and other nacre-mimicking nanocellulose-based materials, e.g., montmorillonite-CNF and graphene oxide-CNF composite films. The excellent mechanical properties are related to the ionic bonds between the negatively charged carboxylic groups on the CNF and the positively charged amine groups on the AC nanoparticles. This work illustrates the significance of tailoring the interactions between small clay particles and biopolymers in multifunctional materials with potential applications as printable barrier coatings and substrates for optoelectronics.

Inverse Nacre-like Epoxy-Graphene Layered Nanocomposites with Integration of High Toughness and Self-Monitoring

“…In contrast, a crack in the bioinspired E-GC-III nanocomposite grows in a tortuous way, as shown in Figure 4B and Video S2. During crack propagation, crack deflection and crack branching, which are the main contributors to the extrinsic toughening of E-GC-III nanocomposite, dissipate a large amount of energy, [49][50][51][52][53] as shown in Figures 4B-4D. In addition, frictional slide between the epoxy layers can also dissipate energy in the process of crack propagation because of the rough interfaces of the E-GC-III nanocomposite ( Figure 4D).…”

Surface Charges Control the Structure and Properties of Layered Nanocomposite of Cellulose Nanofibrils and Clay Platelets

“…The nacre-like hybrid films of the exfoliated aminoclays and carboxylated CNFs displayed a synergistic high tensile strength and large strain-to-failure owing to the ionic bonding between anionic CNFs and cationic clay. 25 Thus, both cationic and anionic surface charged CNFs have been previously used in the layered nanocomposites of CNFs/clay and demonstrated an improved mechanical performance. However, the effect of different surface charge interactions on the structure and properties of the CNFs/clay nanocomposite was not studied and systematically compared previously.…”

Bioinspired Environmentally Friendly Amorphous CaCO3-Based Transparent Composites Comprising Cellulose Nanofibers

“…51−56 The present CMC/CNF/ACC composite films exhibit around 90% of transparency at 600 nm, which is comparable to that of the state-of-the-art composite films based on CNFs with inorganic components. 57−59 In addition to the high transparency, 40/40/20 (CMC/CNF/ACC) showed 260 ± 20 MPa tensile strength and 15.8 ± 0.93 GPa Young’s modulus, which are comparable to other tailor-made composite films based on CNFs. 51−53,58,59…”

“…57−59 In addition to the high transparency, 40/40/20 (CMC/CNF/ACC) showed 260 ± 20 MPa tensile strength and 15.8 ± 0.93 GPa Young’s modulus, which are comparable to other tailor-made composite films based on CNFs. 51−53,58,59…”