Antibacterial
air filtration membranes are essential for personal
protection during the pandemic of coronavirus disease 2019 (COVID-19).
However, high-efficiency filtration with low pressure drop and effective
antibiosis is difficult to achieve. To solve this problem, an innovative
electrospinning system with low binding energy and high conductivity
was built to enhance the jet splitting, and a fluffy nanofibrous membrane
containing numerous ultrafine nanofibers and large quantities of antibacterial
agents was achieved, which was fabricated by electrospinning polyamide
6 (PA6), poly(vinyl pyrrolidone) (PVP), chitosan (CS), and curcumin
(Cur). The filtration efficiency for 0.3 μm NaCl particles was
99.83%, the pressure drop was 54 Pa, and the quality factor (QF) was
up to 0.118 Pa–1. CS and Cur synergistically enhanced
the antibacterial performance; the bacteriostatic rates against Escherichia coli and Staphylococcus
aureus were 99.5 and 98.9%, respectively. This work
will largely promote the application of natural antibacterial agents
in the development of high-efficiency, low-resistance air filters
for personal protection by manufacturing ultrafine nanofibers with
enhanced antibiosis.
Highly efficient air filtration with low pressure drop is the key to air purification. In this work, a self-powered electrospun nanofiber membrane with an electrostatic adsorption effect was prepared to improve the filtration efficiency of micro/nano particles. The composite membrane was comprised of polyvinyl chloride (PVC) nanofibers and polyamide-6 (PA6) nanofibers. The triboelectric effect between the two adjacent nanofiber membranes generated electrostatic charges under the action of air vibration, by which the electrostatic adsorption with the same pressure drop was enhanced. The electrostatic voltage on the self-powered nanofiber membrane was 257.1 mV when the flow velocity was 0.1 m/s. For sodium chloride (NaCl) aerosol particles with a diameter of 0.3 μm, the removal efficiency of the self-powered composite nanofiber membrane was 98.75% and the pressure drop was 67.5 Pa, which showed a higher quality factor than the membrane without electrostatic charges. This work provides an effective way to improve the filtration performance of air filter membranes.
The
Janus membrane has a huge prospect for personal comfortable
protection. However, there still is a huge imbalance between the comfort
and protection of the existing Janus membrane. There is an urgent
need to further improve the comprehensive performance of the protective
membrane to realize both protection and comfort. Herein, we report
the Janus membrane with directional water transport capacity and dust
rejection performance by compounding the polyvinyl chloride hydrophobic
nanofiber membrane and polyamide-6 blended polyvinyl pyrrolidone hydrophilic
nanofiber membrane. This Janus composite nanofiber membrane exhibited
an excellent dust rejection efficiency of 99.99%, air permeability
of 42.15 mm/s, which was 76 times that of the commercial waterproof
and breathable PTFE membrane, water vapor transmission rate of 4.89
kg/(m2 × 24 h), and accumulative one-way transport
capacity of 888.7%. In addition, the breakthrough pressure of the
Janus membrane in the reverse direction (i.e., hydrophilic layer to
hydrophobic layer) was four times that in the positive direction (i.e.,
hydrophobic layer to hydrophilic layer), suggesting it to be a potential
substrate for comfortable bioprotection with a comprehensive protection
capability.
Self-pumping
wound dressings with directional water transport ability
have been widely studied for their function of directional extraction
of excessive biofluid from wounds while keeping the wound in a moderately
humid environment to realize rapid wound healing. However, the existing
solutions have not paid close attention to the fabrication of a nonirritating
hydrophobic layer facing the wounds, which may cause irritation to
wounds and thereby further worsen inflammation. Herein, a flexible
and elastic thermoplastic polyurethane (TPU) hydrophobic microfiber
mesh (TPU-HMM) produced by melt electrospinning (MES) is reported.
The TPU-HMM was compounded to a hydrophilic nanofiber membrane, which
was fabricated by blending with polyamide 6 and poly(ethylene glycol)
(PA6-PEG) to form a composite self-pumping dressing, for which the
breakthrough pressure in a reverse direction was 12.8 times than that
in a positive direction and the forward water transmission rate was
increased by 700%. It shows good directional water transport ability
and is expected to absorb excessive biofluid of the wounds. This solvent-free
and easy-process TPU-HMM provides a new strategy for the development
of functional self-pumping textiles, and the solvent-free fabrication
method for fibers, which eliminates the potential toxicity brought
by solvent residues, offers more possibilities for its applications
in biomedicine.
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