Mechanical reinforcement of electrospun poly(vinyl alcohol) by α‐FeOOH nanowires

Abstract

We report the mechanical performance of a-FeOOH nanowire reinforced poly(vinyl alcohol) (PVA) composite nanofiber mat, fabricated using straightforward aqueous processing methods. Goethite (a-FeOOH) nanocrystals have a high elastic modulus and -OH rich surface, ensuring strong interactions with hydrophilic polymers and effective reinforcement. Needle-less electrospinning resulted in alignment of the nanowires along fibre axis, as confirmed by transmittance electron microscopy studies. Produced composite PVA nanofibers containing 10 wt% goethite nanoparticles exhibited an outstanding fivefold increase in Young's modulus and 2.5-fold improvement of tensile strength compared to mats of neat PVA. The addition of a-FeOOH had a significant influence on glass transition temperature indicating formation of interphase regions around nanowire inclusions. Observed properties are explained by nanowire grafting in the precursor solution, extensive interactions between the adsorbed PVA chains and the matrix and percolation of interphase regions at 10 wt% a-FeOOH. POLYM. COMPOS., 39:2461-2468

Enhancement of the mechanical properties and thermostability of poly(vinyl alcohol) nanofibers by the incorporation of sodium chloride

“…Kinds of nanoparticles were incorporated into the nanofibers in the electrospinning process, and particles distributed and dispersed along the as‐prepared nanofiber with diameters of few tens of nanometers . In this article, when the jet of the electrospun solution travelled to the receiver, the solvent (H 2 O) evaporated accomplishing with the crystallization of NaCl.…”

Bio‐Inspired Macromolecular Ordering of Elastomers for Enhanced Contact Electrification and Triboelectric Energy Harvesting

“…The increase in hardness is due to reinforcing properties of α-FeOOH nanowires, and indicates good load transfer between polymer and α-FeOOH. [26] Interestingly, the nanoindentation maps revealed a PEBA/α-FeOOH composite possessed heterogenous surface hardness (Figure 2). The addition of α-FeOOH increased the hardness of PEBA by up to 4.5 times (from 2.0 ± 0.3 to 8.9 ± 1.7 MPa).…”

“…This ordering can broadly occur in polymer–nanomaterial composites, and is thought to be induced by strong intermolecular interactions such as hydrogen bonding. [ 26 ] The surface of α‐FeOOH is densely covered by hydroxyl groups (‐OH), [ 27 ] thus ensuring plenty of available sites for hydrogen bonding. Here, we expect goethite to provide the hydrogen bonding between the abundant hydroxyl groups on the surface of goethite and carbonyl (CO) groups in polyamide (PA) blocks or polyether (PE) blocks of elastomeric PEBA matrix.…”

Silica-based fibers with axially aligned mesopores from chitin self-assembly and sol-gel chemistry

“…The long polymer chains often used to produce electrospun fibers have a strong tendency to align during processing with the flow direction due to strong shear forces, sometimes combined with additional external fields [14]. Nanoparticles can also be dispersed within the electrospun fibers [2,15] to improve their mechanical properties [5,16,17] or provide additional functionalities [12,[18][19][20][21][22][23]. Anisotropic nanoparticles such as rods or platelets are often aligned along the long axis of the fiber due to shearing and interactions with the spinning polymer [17,19,20,24].…”

“…Nanoparticles can also be dispersed within the electrospun fibers [2,15] to improve their mechanical properties [5,16,17] or provide additional functionalities [12,[18][19][20][21][22][23]. Anisotropic nanoparticles such as rods or platelets are often aligned along the long axis of the fiber due to shearing and interactions with the spinning polymer [17,19,20,24]. Additionally, applying an external magnetic field can allow fiber alignment [25], and particle alignment inside the fibers like for instance with Ag nanowires in association with PVP [22].…”