Hybrid Sponge Research Articles

ZIF-8/MS Hybrid Sponge via Secondary Growth for Efficient Removal of Pb(II) and Cu(II)

ZIF-8/MS Hybrid Sponge via Secondary Growth for Efficient Removal of Pb(II) and Cu(II)

Highly Salt-Resistant interfacial solar evaporators based on Melamine@Silicone nanoparticles for stable Long-Term desalination and water harvesting

Interfacial solar-driven evaporation (ISE) is one of the most promising solutions for collecting fresh water, however, poor salt-resistance severely limits the long-term stability of solar evaporators. Here, highly salt-resistant solar evaporators for stable long-term desalination and water harvesting were fabricated by depositing silicone nanoparticles onto melamine sponge, and then modifying the hybrid sponge sequentially with polypyrrole and Au nanoparticles. The solar evaporators have a superhydrophilic hull for water transport and solar desalination, and a superhydrophobic nucleus for reducing heat loss. Spontaneous rapid salt exchange and reduction in salt concentration gradient were achieved due to ultrafast water transport and replenishment in the superhydrophilic hull with a hierachical micro-/nanostructure, which effectively prevents salt deposition during ISE. Consequently, the solar evaporators have long-term stable evaporation performance of 1.65 kg m-2h−1 for 3.5 wt% NaCl solution under 1 sun illumination. Moreover, 12.87 kg m−2 fresh water was collected during consecutive 10 h ISE of 20 wt% brine under 1 sun without any salt precipitation. We believe that this strategy will shed a new light on the design of long-term stable solar evaporators for fresh water harvesting.

Multi-functional carboxymethyl chitosan/sericin protein/halloysite composite sponge with efficient antibacterial and hemostatic properties for accelerating wound healing

The development of wound dressings with hemostatic and antibacterial properties has attracted great attention. In this study, we prepared a multi-functional natural substance sponge (CMC/Ser-Ag/HNT) composed of carboxymethyl chitosan (CMC), sericin-silver nanoparticle (Ser-Ag), and halloysite (HNT). CMC/Ser-Ag/HNT sponge was demonstrated to bear desired hygroscopicity, porosity, compressive strength and compressive stability, cytocompatibility, and hemocompatibility. The mechanical properties (compressive strength of 100 kPa) and hemostatic capacity (hemostasis time of 15 ± 3 s in the liver injury model and 12 ± 3 s in the caudal injury model) were enhanced by introducing HNT into the CMC sponge. Ser-Ag was synthesized in situ via the redox nature of tyrosine residues in sericin in a “one-step, green” way to enhance the antibacterial activity of the hybrid sponge against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). In addition, the rat full-thickness skin defect model experiments demonstrated that the CMC/Ser-Ag/HNT4 sponge significantly promoted epithelialization and collagen formation. Immunofluorescence staining assays revealed that the composite sponge reduced inflammation by downregulating the expression of IL-6 and enhanced angiogenesis by upregulating VEGF expression. All the findings demonstrated the great potential of CMC/Ser-Ag/HNT sponge as versatile clinical wound dressing, especially for hemorrhagic and infected wounds.

Biomimetic multifunctional hybrid sponge via enzymatic cross-linking to accelerate infected burn wound healing

Preparing sponge dressings with stable wet adhesion remains difficult in wound repair, especially in burn wounds with bleeding and large amounts of exudate. In this work, a multifunctional hybrid sponge dressing (DHGT+PHMB+TiO2NPs) with good wet adhesion was developed by combining biomimetic and enzymatic cross-linking reactions. The sponge dressing matrix (DHGT) was prepared by tyrosinase-catalyzed cross-linking of dopamine-modified hyaluronic acid (DOPA-HA) and gelatin. The multifunctional hybrid sponge dressing was obtained by loading polyhexamethylene biguanide (PHMB) and titanium dioxide nanoparticles (TiO2NPs) onto the DHGT matrix. The newly developed sponge dressing exhibited high mechanical properties, good wet adhesion, antibacterial activity, reactive oxygen species (ROS) scavenging, biocompatibility, and excellent hemostasis ability. In vivo studies showed that the multifunctional hybrid sponge dressing could significantly accelerate the healing of infected full-thickness burn wounds by inhibiting bacterial growth, accelerating skin tissue reepithelialization, collagen deposition, and angiogenesis, as well as regulating the expression of inflammatory factors and cytokines.

Biocompatible and breathable healthcare electronics with sensing performances and photothermal antibacterial effect for motion-detecting

With the booming development of smart wearable devices, flexible multifunctional composites with high sensitivity and well health therapy have evoked great interest for next-generation healthcare electronics. However, the weak biocompatibility, low breathability, and narrow sensing range greatly hinder the development of healthcare sensors. Herein, a porous, flexible and conductive MXene/Polydimethylsiloxane/Polydopamine/Polyurethane Sponge (MXene/PDMS/PDA/PU) nanocomposite is developed as a promising motion-detecting device with good flexibility, breathability, sensing performance, photothermal therapy and antibacterial activity. Benefiting from the porous structure and biocompatible surface, this multifunctional sensor is further fabricated into a diagnostic and therapeutic system for monitoring human body motion and performing hot therapy/antibacterial treatment in the application of sports injury site. Moreover, both the wireless smart insole and cushion are constructed to gait monitoring and sit position detecting. This multifunctional hybrid sponge not only demonstrates great potential for motion monitoring sensors but also exhibits wide potential in wearable medical assistive and therapeutic systems.

Conducting polypyrrole silicotungstate deposited on macroporous melamine sponge for electromagnetic interference shielding

Macroporous melamine/formaldehyde sponge was coated in situ during the oxidation of pyrrole with iron(III) chloride hexahydrate in aqueous medium. The reaction mixture contained a heteropolyacid, silicotungstic acid, which protonated polypyrrole. Polypyrrole/silicotungstate deposits were prepared either in globular form or as nanotubes. The resulting hybrid composites thus combine an organic conducting polymer with inorganic component known, e.g., for its proton conductivity and electrocatalytic activity. The specific surface area of all materials was of the order of tens m2g−1. The molecular structure is discussed on the basis of FTIR and Raman spectra. The resistivity of the sponges was recorded as a function of compression to 10 MPa and it decreased from the order of 10 Ω cm to 0.1 Ω cm. The sponges were tested in electromagnetic interference shielding and absorbed over 80% of 9 GHz radiation frequency. The shielding is based mainly on the radiation absorption efficiency, −8.2 dB for globular polypyrrole and −13.1 dB for nanotubes, afforded by silicotungstic component. Hybrid composite sponges were subsequently carbonized at 650 °C in inert atmosphere when they converted to a sponge-like macroporous carbons enriched with nitrogen atoms. Their resistivity increased by two orders of magnitude after this process. The absorption of electromagnetic radiation, however, fell below 10%. Original and carbonized hybrid sponges may be of interest in the construction of macroporous electrodes.

Carbon nanotube-vertical edge rich graphene hybrid sponge as multifunctional reinforcements for high performance epoxy composites

Thermal management materials with excellent electromagnetic interference (EMI) shielding performance have attracted research interest in the field of modern electronic devices. Herein, vertical edge rich graphene (VG) was in-situ grafted on the carbon nanotube (CNT) sponge to create connective 3D hybridized carbon skeleton with covalent bonding, then CNT-VG/epoxy composites were constructed to meet the needs of multifunctional application. Impressively, mainly owing to the connectivity of 3D CNT sponge, the conduction ability of interfaces and the defect-rich structure of VG, the obtained CNT-VG/epoxy composites possessed an enhanced EMI shielding effectiveness of 46.9 dB with a thickness of 1 mm and an improved thermal conductivity of 2.23 W m−1 K−1 which contributes to superior thermal management capability. In addition, the excellent structural design also increases the flexural strength by 349.39% compared to pure epoxy resin, achieving a flexural strength of 275.32 MPa and a work of fracture of 9956.98 kJ m−3. The novel multifunctional CNT-VG/epoxy composites with enhanced mechanical property show a bright application prospect in next-generation electronic devices.

Anchoring Oxidized MXene Nanosheets on Porous Carbon Nanotube Sponge for Enhancing Ion Transport and Pseudocapacitive Performance.

Two-dimensional (2D) MXene nanosheets are attractive for electrochemical energy storage applications due to their superior surface-controlled charge storage capacity. However, the slow ion transport in the closely packed electrode limits their electrochemical performances. Meanwhile, the restricted surface-controlled pseudocapacitance of MXene nanosheets requires to be enhanced. Herein, a well-controlled electrophoretic deposition strategy is developed to disperse Ti3C2Tx nanosheets into a freestanding, porous carbon nanotube (CNT) sponge. The constructed Ti3C2Tx@CNT hybrid sponge can provide high-speed ion-transport pathways for the charge-discharge process. Furthermore, by tuning the deposition potential, the inserted MXene nanosheets can be partially oxidized, boosting the pseudocapacitance performance. A large gravimetric capacitance of 468 F g-1 at 10 mV s-1 and a retention of 79.8% at 100 mV s-1 can be achieved in the Ti3C2Tx@CNT electrode. Meanwhile, the highest areal capacitance of 661 mF cm-2 at 1 mA cm-2 was obtained in the sample with high-loading Ti3C2Tx. For the assembled symmetric supercapacitor, 92.8% of the capacitance is retained after 10 000 cycles of the charge-discharge process at 10 mA cm-2. Thus, this study develops a promising electrophoretic deposition strategy for dispersing 2D MXene nanosheets and boosting their pseudocapacitive performance, resulting in a high-capacitive electrochemical energy storage electrode.

Portable and durable sensor based on porous MOFs hybrid sponge for fluorescent-visual detection of organophosphorus pesticide

Pesticide residues have raised serious public concern towards agriculture, environment and food safety. Recently, metal-organic frameworks (MOFs) have been employed as promising recognition and signal generation elements in sensors for pesticide detection. However, the general format of tiny particles with poor dispersity brings obstacles to detection operation and the improvement of sensing performance. Here, we report a sensor based on porous MOFs hybrid sponge for fluorescent-visible detection of methyl parathion. Benefiting from the intermediate of adhesive and porous fibrin film, MOFs are loaded with good dispersion and accessibility, thereby endowing the sensor with a rapid response time of 10-min, a wide linear detection range of 50–2500 μg L-1, and a low limit of detection of 4.95 μg L-1. Moreover, the hybrid sensor presented superior durability and anti-interference ability to the detection in complex conditions, including organic solvents, acidic solution, high temperature, and even chemical interferences. This hybrid not only provides a new construction strategy for a nanomaterial-based sensor, but also permits a portable and durable route for the detection.

Monolithic robust hybrid sponge with enhanced light adsorption and ultrafast photothermal heating rate for rapid oil cleaning

It remains a significant challenge to develop a photothermal adsorbent with a heating response as fast as a joule-heating adsorbent and simultaneously possessing excellent mechanical stability and reusability for rapid oil cleaning. Here, we report a novel monolithic design to fabricate a photothermal hybrid sponge for rapid oil cleaning by integrating graphite interlayer compounds as photothermal units into the three-dimensional photothermal network of carbon nanotubes. This unique monolithic design enabled the hybrid sponge to present excellent photothermal performance: firstly, the superhydrophobic hybrid sponge has low thermal resistance resulting from the defectless surface; secondly, the photothermal units were weaved in the photothermal network, preventing detachment in the cycling and providing ultrafast photothermal heating rate. The hybrid sponge rises to 81 °C in merely 25 s under irradiation (1 Sun), superior to most photothermal oil adsorbents reported so far. This study provides a new structural design for constructing photothermal adsorbents with a fast-heating response for rapid crude oil cleaning.

Highly Elastic Melamine Graphene/MWNT Hybrid Sponge for Sensor Applications

The rapidly increased interest in multifunctional nanoelectronic devices, such as wearable monitors, smart robots, and electronic skin, motivated many researchers toward the development of several kinds of sensors in recent years. Flexibility, stability, sensitivity, and low cost are the most important demands for exploiting stretchable or compressible strain sensors. This article describes the formation and characteristics of a flexible, low-cost strain sensor by combining a commercial melamine sponge and a graphene/carbon nanotubes hybrid. The composite that emerged by doping the highly elastic melamine sponge with a highly conductive graphene/carbon nanotubes hybrid showed excellent piezoresistive behavior, with low resistivity of 22 kΩ m. Its function as a piezoresistive material exhibited a high sensitivity of 0.050 kPa−1 that combined with a wide detection area ranging between 0 to 50 kPa.

Collective, bifunctional 1D CNT/2D TMOH hybrid sponge as high-capacity and long-cycle Li-O2 cathode

Owing to their bifunctional catalytic advantages such as oxygen evolution reaction (OER) and oxygen reduction reaction (ORR), two-dimensional (2D) transitional metal hydroxide (TMOH) nanosheets exhibit promising catalytic activity as metal-air batteries electrodes, however currently it remains challenging to achieve both high capacity and long cyclic life. Here, we combine 2D TMOHs with 1D carbon nanotubes (CNTs) to construct a mutually interpenetrated hybrid structure, in which the CNT network acts as a porous conductive skeleton and the TMOH sheets behave as a bifunctional catalytic substrate to deposit discharge product effectively. Such a collective function results in superior properties when serving as a lithium-oxygen cathode, exhibiting long cycle life of 300 cycles under areal capacity limit of 0.5 mAh cm−2, and 178 cycles (∼1400 hours) even at 2 mAh cm−2. Our mixed-dimensional hybrid electrodes offer a promising route in developing high performance electrochemical catalysis and energy storage systems.

Catalytic Performance of Pd Nanoparticles Obtained by Direct Reduction in Cellulose–Poly(ferrocenylsilane) Hybrid Sponges

AbstractCellulose–poly(ferrocenylsilane) (PFS) polyionic liquid (PIL) composite sponges are fabricated by codissolution of cellulose and PFS‐PIL, followed by solvent exchange and freeze‐drying. The hybrid sponges are used to in situ produce and immobilize palladium nanoparticles (Pd NPs), leading to Pd NP‐decorated porous supports. The formation of Pd NPs is confirmed by TEM and XPS measurements. The as‐prepared cellulose/PFS‐PIL@Pd sponges exhibit a high catalytic activity in the reduction of 4‐nitrophenol (4‐NiP) to 4‐aminophenol (4‐AmP). As a variety of metal NPs may be immobilized using this method, these sponges constitute a promising new class of catalytic porous supports.

Multifunctional Phase Change Composites Based on Elastic MXene/Silver Nanowire Sponges for Excellent Thermal/Solar/Electric Energy Storage, Shape Memory, and Adjustable Electromagnetic Interference Shielding Functions.

Multifunctional phase change materials (PCMs) are highly desirable for the thermal management of miniaturized and integrated electronic devices. However, the development of flexible PCMs possessing heat energy storage, shape memory, and adjustable electromagnetic interference (EMI) shielding properties under complex conditions remains a challenge. Herein, the multifunctional PCM composites were prepared by encapsulating poly(ethylene glycol) (PEG) into porous MXene/silver nanowire (AgNW) hybrid sponges by vacuum impregnation. Melamine foams (MFs) were chosen as a template to coat with MXene/AgNW (MA) to construct a continuous electrical/thermal conductive network. The MF@MA/PEG composites showed a high latent heat (141.3 J/g), high dimension retention ratio (96.8%), good electrical conductivity (75.3 S/m), and largely enhanced thermal conductivity (2.6 times of MF/PEG). Moreover, by triggering the phase change of the PEG, the sponges displayed a significant photoinduced shape memory function with a high shape fixation ratio (∼100%) and recovery ratio (∼100%). Interestingly, the EMI shielding effectiveness (SE) can be adjusted from 12.4 to 30.5 dB by a facile compression-recovery process based on shape memory properties. Furthermore, a finite element simulation was conducted to emphasize the advantage of the MF@MA/PEG composites in the thermal management of chips. Such flexible PCM composites with high latent heat storage, light-actuated shape memory, and adjustable EMI shielding functions exhibit great potential as smart thermal management materials in military and aerospace applications.

Scalable, superelastic, and superhydrophobic MXene/silver nanowire/melamine hybrid sponges for high-performance electromagnetic interference shielding

MXene/silver nanowire/melamine (MS–MAF) hybrid sponges are fabricated via a facile and scalable method. The MS–MAF hybrid sponge exhibits excellent superelasticity, superhydrophobicity, and electromagnetic interference (EMI) shielding performance.

Melamine/Silicone Hybrid Sponges with Controllable Microstructure and Wettability for Efficient Solar-Driven Interfacial Desalination.

Solar-driven interfacial evaporation (SIE) has received extensive attention as a very promising desalination technique to solve the fresh water shortage crisis. However, evaporation rate decline and salt-fouling during long-term SIE seriously hinder applications of solar evaporators. Here, we report the preparation of melamine/silicone (MS) hybrid sponges with controllable microstructure and wettability for efficient SIE by further combination with carbon nanotubes (CNTs). The MS sponges are synthesized by hydrolytic condensation and phase separation of two silanes in the melamine sponge. The microstructure and wettability of the MS sponges are highly controllable by the silanes concentration. The CNTs@MS solar evaporators have a unique three-tier hierarchical macro-/micro-/nanostructure, very low thermal conductivity as well as a superhydrophilic hull and a superhydrophobic nucleus. Consequently, the CNTs@MS solar evaporators show a highly stable evaporation rate of ∼1.75 kg m-2 h-1 without any salt precipitation during a long-term cyclic solar desalination of 3.5 wt % NaCl solution under 1 sun illumination. Furthermore, salt precipitation is completely hindered even during SIE of 20 wt % NaCl solution under 1 sun. The CNTs@MS solar evaporators are very promising for practical SIE because of their excellent performance and simple preparation method.

Molecular Ferroelectric-Based Flexible Sensors Exhibiting Supersensitivity and Multimodal Capability for Detection.

Although excellent dielectric, piezoelectric, and pyroelectric properties matched with or even surpassing those of ferroelectric ceramics have been recently discovered in molecular ferroelectrics, their successful applications in devices are scarce. The fracture proneness of molecular ferroelectrics under mechanical loading precludes their applications as flexible sensors in bulk crystalline form. Here, self-powered flexible mechanical sensors prepared from the facile deposition of molecular ferroelectric [C(NH2 )3 ]ClO4 onto a porous polyurethane (PU) matrix are reported. [C(NH2 )3 ]ClO4 -PU is capable of detecting pressure of 3Pa and strain of 1% that are hardly accessible by the state-of-the-art piezoelectric, triboelectric, and piezoresistive sensors, and presents the ability of sensing multimodal mechanical forces including compression, stretching, bending, shearing, and twisting with high cyclic stability. This scaling analysis corroborated with computational modeling provides detailed insights into the electro-mechanical coupling and establishes rules of engineering design and optimization for the hybrid sponges. Demonstrative applications of the [C(NH2 )3 ]ClO4 -PU array suggest potential uses in interactive electronics and robotic systems.

A scalable, cost-effective and salt-rejecting MoS2/SA@melamine foam for continuous solar steam generation

Solar steam generation (STG) has been regarded as a promising strategy to relieve concerns on water shortage. Though great progresses have been made to improve the efficiency, salt deposition in the STG evaporator presents vital issues to an effective and continuous water production. Here, A MoS2-sodium alginate hydrogel wrapped melamine foam (MoS2/[email protected]) hybrid sponge is developed through simple, scalable and low-cost dipping–drying–crosslinking process. In this work, a 4 × 4 cm MoS2/[email protected] evaporator shows an evaporation rate of 1.92 kg/m2.h in 3.5 wt% NaCl solution under 1 kW.m−2, achieving a solar-thermal conversion efficiency of 90%. Additional to bimodal porous structure of the MF skeleton, thanks to meticulous designs, including drilling through-holes and cutting water-channels on the STG evaporator, the water transportation and salt ions convection are fully accelerated. It is systematically illustrated that a significant improvement in salt rejecting performance is achieved with a 1.81 kg/m2.h evaporation rate even after 100 h in a brine salinity up to 20 wt% under 1 kW.m−2. In addition, a consistent and effective solar-thermal conversion efficiency of 84.8% is also achieved superior to most reported works. Furthermore, this work also reveals that, in case of putting the evaporator float on the brine solution, Marangoni effect stemming from the temperature gradient and salinity concentration gradient at saltwater-air interface, plays an important role in salt deposition in the edge of PS foam and the side of MoS2/[email protected] hybrid sponge. The study also provides an effective strategy of isolating the evaporator from brine water to prevent Marangoni flow and enable its sustainable and practical applications.

Janus hybrid sustainable all-cellulose nanofiber sponge for oil-water separation

Two-faced characteristics and performance of materials driven by asymmetric physical or chemical properties exist in Janus hybrid materials which show synergistic and improved properties for a variety of applications. Here, we report a facile synthesis of Janus hybrid sustainable cellulose nanofibers (CNFs) sponge with asymmetric wettability and strong mechanical property for excellent separation efficiency of oil-water emulsions. Briefly, the CNF Janus hybrid sponge was fabricated by freeze-drying of two separate CNF suspensions into one, each prepared separately by introducing CNFs in methyltrimethoxysilane (MTMS) or 3-glycidoxypropyltrimethoxysilane (GPTMS) for hydrophobic or hydrophilic performance, respectively. The sponge demonstrated satisfactory mechanical stability with an excellent recovery from 80% compressive strain and high pore tortuosity. When employed for oil-water separation, the Janus hybrid sponge could selectively be used to collect water or oil by just switching its side facing the oil-water mixture feed via unidirectional gravity-assisted separation, with recyclability. The fabrication of such Janus hybrid sponge is one of the many approaches for utilizing nanofibers in structurally adaptive, self-supported asymmetric membrane structures in a 3D network.

Highly efficient method of utilizing waste silica hazards

Silica gels are the significant commodity solid waste produced by organic laboratories and pharmaceutic industries. Although use of silica gels is continuously growing, the proper methods of re-utilizing silica waste are yet limited. Hence, it demands a non-traditional approach to transform these silica waste into some other useful products apart from using them as a well-known road construction materials. Hereby, we report the fabrication and applications of monolithic polymer-silica composites by ice-templating technique from laboratory waste silica-gels, using green approach. To the best of our knowledge, the fabrication of organic-inorganic hybrid sponges from the particles of hundreds of microns is not reported to date. Scaffolds S60, S120, S180, and S300, were prepared from laboratory discarded silica gels. The morphological, physicochemical, flame-retardant, and liquid absorbent properties of these self-standing scaffolds were analyzed. Results showed that the incorporation of silica particles in the scaffolds turned them into a flame-retardant sponge. These properties make the sponges ideal for making non-flammable cushions, applicable in automobiles, aircrafts, chemical laboratories, hospitals, and other areas of applications. Due to the large porous structures, these scaffolds possess excellent absorption properties and may absorb almost every kind of liquid ranging from oils to acids. Therefore, these scaffolds are also a remarkable absorber for oils and hazardous liquids spillage, such as acids, and can be used as foam for chemical packing applications.