Abstract:Advanced medical dressings need to meet these requirements of breathability, moisture absorption balance, antibacterial activity, and mechanical strength. Both breathability and moisture absorption balance strongly depend on the porous structure that inversely sacrifice their mechanical properties and bulk antibacterial activity. Herein, multifunctional porous structure is designed that can synchronously realize excellent antibacterial activity, breathability, superhydrophilicity, and enhanced mechanical prope… Show more
“…Some small materials were observed on the surface of the bacteria, which originated from the attached CDFs. This indicates the CDFs can disinfect the bacterial cells by damaging the membranes [ 32 ]. Fig.…”
Carbon dots (CDs) have been widely used as antimicrobials due to their active surface, but some CDs suffer instability. Therefore, the relative applications such as the antibacterial activity may not be reliable for long-term use. Herein, we synthesize CDs with blue fluorescence by a hydrothermal process. Thereafter, polyethylenimine was applied for the assembly of CDs into CDs-based frameworks (CDFs). The CDFs exhibited quenched fluorescence but showed more stable properties based on the scanning electron microscope and zeta potential investigations. Both CDs and CDFs show antibacterial activity toward Gram-negative Escherichia coli (E. coli) and Gram-positive Staphylococcus aureus (S. aureus), but CDFs exhibited better antibacterial performance, and S. aureus could be completely inhibited with the minimum inhibitory concentration of 30 μg/mL. This reveals CDFs magnify both the stability and antibacterial activity, which would be more promising for practical applications.
Graphic abstract
“…Some small materials were observed on the surface of the bacteria, which originated from the attached CDFs. This indicates the CDFs can disinfect the bacterial cells by damaging the membranes [ 32 ]. Fig.…”
Carbon dots (CDs) have been widely used as antimicrobials due to their active surface, but some CDs suffer instability. Therefore, the relative applications such as the antibacterial activity may not be reliable for long-term use. Herein, we synthesize CDs with blue fluorescence by a hydrothermal process. Thereafter, polyethylenimine was applied for the assembly of CDs into CDs-based frameworks (CDFs). The CDFs exhibited quenched fluorescence but showed more stable properties based on the scanning electron microscope and zeta potential investigations. Both CDs and CDFs show antibacterial activity toward Gram-negative Escherichia coli (E. coli) and Gram-positive Staphylococcus aureus (S. aureus), but CDFs exhibited better antibacterial performance, and S. aureus could be completely inhibited with the minimum inhibitory concentration of 30 μg/mL. This reveals CDFs magnify both the stability and antibacterial activity, which would be more promising for practical applications.
Graphic abstract
“…For breathable membranes, the structural characteristics of the upper and lower surfaces have an important influence on performance 32–34 . Therefore, the scanned photos of the surface and the three‐dimensional topography were observed in Figure 2 and Figure 3, respectively.…”
Multifunctional membranes with outstanding heat dissipation, wave‐transparent, and self‐cleaning performance, as well as strength and ventilation, are urgently needed to meet the rapid development of portable electronics. Herein, we reported an improved phase separation process to prepare thermoplastic polyurethane (TPU)/multi‐wall carbon nanotube (MWCNT) composite membranes with open‐cell porous structure. Their morphology can be manipulated by regulating the content of MWCNT and varying processing parameters. These TPU/MWCNT composite membranes exhibit outstanding mechanical properties. For example, they can possess elastic deformation behavior in a wide temperature range from −50 to 100°C, and bear a load of more than 40,000 times their own weight. Moreover, there is not any obvious crease on the surface of membranes after a forced folding process, indicating their outstanding shape‐recovery ability and elasticity. Furthermore, these membranes have low dielectric constant and loss factor, and they are almost transparent to X‐band electromagnetic waves. What's more, these membranes also show outstanding water‐vapor breathable performance. In addition, MWCNT and open‐cell porous structure endow TPU/MWCNT membranes efficient heat dissipation capacity and good self‐cleaning performance.
“…Recently, various 2D materials, including zeolites, − metal–organic frameworks (MOFs), − graphene, − MXenes, − h-BN, − TMDs, − and other nanosheet materials, − are widely used for high separation performance membranes due to their 2D layered structure, which makes them easy to prepare and modify to separate different molecules. − However, conventional polymer films cannot exist stably in complex environments, such as high temperatures, strong acids/bases, organic solvents, or corrosive environments . While the porous ceramic membrane overcomes the above shortcomings, the preparation process is complicated, the price is very expensive, and the brittleness is large, as it is easily broken during the pressure driving process .…”
Advanced
membrane separation technology plays an important role
in achieving excellent water treatment, which can help solve the freshwater
crisis. However, there remains a trade-off between membrane permeability
and selectivity. An emerging candidate to address this issue is graphene
oxide (GO), a two-dimensional (2D) laminated graphene derivative with
abundant oxygen functional groups. Furthermore, the transport channels
of GO-based membranes can be artificially modified and manipulated,
exhibiting great promise for GO in the field of water purification
and molecular separation. This review comprehensively summarizes the
research advances on 2D GO-based membranes for high-performance nanofiltration
(NF). It begins with an elaboration on the preparation methods of
GO-based membranes, followed by a detailed summary of the chemical
modification and physical manipulation of transport channels. Then
we reviewed the current research progress of theoretical calculation
and molecular dynamics simulation. Also, the high NF performance of
GO-based membranes is presented. Finally, the remaining challenges
and future prospects in order to develop advances in membrane technology
are provided.
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