Composite Sponge Research Articles

The stable and elastic graphitic carbon nitride/polyvinyl alcohol photocatalytic composite sponge: Simple synthesis and application for wastewater treatment

Nanosized photocatalysts have the obvious disadvantages in recovering and recycling process during the wastewater treatment. To overcome the above shortcomings, graphitic carbon nitride/polyvinyl alcohol (g-C3N4/PVA) photocatalytic composite sponge was prepared simply by introducing graphitic carbon nitride (g-C3N4) photocatalyst into polyvinyl alcohol (PVA) sponge via copolymerization method during the cross-linking process. The characterization results indicated that the g-C3N4/PVA composite sponge has the porous structure and g-C3N4 nanoparticles have been attached uniformly and tightly throughout the porous structure of the PVA sponge. Furthermore, the composite sponge has excellent elastic deformation property and can be easily tailored into designed shapes without destroying the structure of the sponge. Thirdly, the composite sponge shows efficient adsorption and photodegradation properties for removing of organic pollutants rhodamine B (RhB) and tetracycline (TC) from wastewater. It is worth to note that the prepared g-C3N4/PVA composite sponge can be easily recovered from the wastewater solution and shows stable recycling property. Our method to combine g-C3N4 photocatalysts into PVA sponge provides a facile technique to construct stable photocatalysts with recyclable and photocatalytic degradation properties in the field of wastewater treatment.

A quaternized chitin derivatives, egg white protein and montmorillonite composite sponge with antibacterial and hemostatic effect for promoting wound healing

In this study, we prepared an all-natural substances based sponge (EMQS) consist of egg white protein (EW), quaternized chitin derivatives (QCs) and montmorillonite (MMT). Inspired by the cuisine method of pastry, EW was separated from yolk and mechanically stirred vigorously to generate fluffy and porous foam. The incorporation of MMT enhanced the mechanical properties (a compressive strength of 0.126 MPa), as well as the hemostatic effect of the sponge (hemostasis time of 49.7 ± 8.0 s in a liver injury model). The QCs improved the antimicrobial activities of EMQS against Escherichia coli (E.Coli) and Methicillin-resistant Staphylococcus aureus ( MRSA ) . The 3D porous structure of EMQS, coming with beneficial properties including high porosity (84.8%), water uptake ability of 675.3 g/g and water vapor transmission rate satisfied the requirements for soft-tissue-engineering applications. QCs interacted with MMT via hydrogen bonding and electronical interaction so that it served as a sustainable drug release system at wound site with excellent antibacterial activity. Three full-thickness skin defect models of BALB/c mice indicated that this sponge could effectively shorten the healing time and accelerate the angiogenesis and collagen deposition of uninfected, E.Coli and MRSA infected wounds in comparison with commercial dressings. Hence, this all-natural substances based sponge with antibacterial property and hemostatic effect had a great potential as a clinical dressing for skin regeneration. • A quaternized chitin, egg white protein and montmorillonite sponge was prepared. • The sponge showed high porosity and good water uptake ability. • The sponge displayed excellent antibacterial activity and hemostatic ability. • The sponge could significantly accelerate E.coli and MRSA infected wounds healing.

MXene-Enhanced Chitin Composite Sponges with Antibacterial and Hemostatic Activity for Wound Healing.

This study shows the effective use of MXene-based nanomaterials to improve the performance of biocomposite sponges in wound healing. In this way, diverse chitin/MXene composite sponges are fabricated by incorporating MXene-based nanomaterials with various morphology (accordion-shaped, intercalated, single-layer, gold nanoparticles (AuNPs)-loaded single-layer) into the network of chitin sponge (CH), which can prevent massive blood losses and promote the healing process of bacterial-infected wounds. With the addition of MXene-based nanomaterials, the hemostatic efficacy of CH is enhanced due to the improved hemophilicity and accelerated blood coagulation kinetics. Furthermore, the composite sponges show a predominant antibacterial activity through the synergy between the capture and the photothermal effects. Importantly, the addition of AuNPs to composite sponges further improves hemostatic performance and promotes normal skin cell migration to heal the infected wound, achieving wound closure rates of 84% on day 9. These initial studies expand the applications of MXene-based nanomaterials in biomedical fields.

Environmentally Benign Biosynthesis of Hierarchical MOF/Bacterial Cellulose Composite Sponge for Nerve Agent Protection

AbstractThe fabrication of MOF polymer composite materials enables the practical applications of MOF‐based technology, in particular for protective suits and masks. However, traditional production methods typically require organic solvent for processing which leads to environmental pollution, low‐loading efficiency, poor accessibility, and loss of functionality due to poor solvent resistance properties. For the first time, we have developed a microbial synthesis strategy to prepare a MOF/bacterial cellulose nanofiber composite sponge. The prepared sponge exhibited a hierarchically porous structure, high MOF loading (up to ≈90 %), good solvent resistance, and high catalytic activity for the liquid‐ and solid‐state hydrolysis of nerve agent simulants. Moreover, the MOF/ bacterial cellulose composite sponge reported here showed a nearly 8‐fold enhancement in the protection against an ultra‐toxic nerve agent (GD) in permeability studies as compared to a commercialized adsorptive carbon cloth. The results shown here present an essential step toward the practical application of MOF‐based protective gear against nerve agents.

Environmentally Benign Biosynthesis of Hierarchical MOF/Bacterial Cellulose Composite Sponge for Nerve Agent Protection.

The fabrication of MOF polymer composite materials enables the practical applications of MOF-based technology, in particular for protective suits and masks. However, traditional production methods typically require organic solvent for processing which leads to environmental pollution, low-loading efficiency, poor accessibility, and loss of functionality due to poor solvent resistance properties. For the first time, we have developed a microbial synthesis strategy to prepare a MOF/bacterial cellulose nanofiber composite sponge. The prepared sponge exhibited a hierarchically porous structure, high MOF loading (up to ≈90 %), good solvent resistance, and high catalytic activity for the liquid- and solid-state hydrolysis of nerve agent simulants. Moreover, the MOF/ bacterial cellulose composite sponge reported here showed a nearly 8-fold enhancement in the protection against an ultra-toxic nerve agent (GD) in permeability studies as compared to a commercialized adsorptive carbon cloth. The results shown here present an essential step toward the practical application of MOF-based protective gear against nerve agents.

Lightweight and anisotropic cellulose nanofibril/rectorite composite sponges for efficient dye adsorption and selective separation

Constructing lightweight and porous adsorbents which can effectively remove dye contaminants is of great significance in the field of the sewage treatment. In this work, anisotropic cellulose nanofibril (CNF) composite sponges assisted by rectorites are fabricated through directional freeze-drying. The resulted composite sponge exhibits the superior saturated adsorption capacity and removal efficiency of 120.0 mg/g and 96.1% for methylene blue (MB), respectively, which is better than the pure CNF sponge and rectorite powders. This is attributed to the strong electrostatic interaction between CNFs and MB, and good cation exchange property of rectorites inside the three-dimensional (3D) highly porous composite sponge. The MB adsorption process of the composite sponge fits to the pseudo-second-order kinetic model and the Langmuir isotherm model well, which is affected by both boundary layer and intraparticle diffusion, resulting in a theoretical maximum adsorption capacity of 214.6 mg/g. Moreover, it also possesses a selective adsorption capacity for anionic and cationic dyes, which is expected to realize the separation treatment of different dyes according to actual application requirements.

Multifunctional conductive graphite/cellulosic microfiber-natural rubber composite sponge with ultrasensitive collision-warning and fire-waring

• GP/CMF-NR sponge was prepared by a combined strategy of freeze and vulcanization. • The existence of CMF could improve the deposition and agglomeration of GP in NRL. • GP/CMF-NR sponge could be applied for human motion detection and collision warning. • GP/CMF-NR sponge triggered the fire-warning within 1.2 s when encountering fire. Design and development of the conductive polymer composite sponges with multifunctionality are urgently needed to expand and meet their application in multiple fields. Herein, we proposed an ingenious strategy to fabricate the graphite (GP)/cellulosicmicrofiber (CMF)-natural rubber (NR) composite sponges though freezing at low temperature (to build the skeleton structure of sponge) and vulcanizing at high temperature (to form the pores and fix the skeleton structure of sponge). Meanwhile, the incorporation of CMF can help GP to disperse uniformly in NRL and form an entire conductive network. As results shown, GP/CMF-NR composite sponge exhibits the excellent compressive property and electrical conductivity due to the good elasticity of NR and the support strength of CMF. Significantly, GP/CMF-NR composite sponge has been successfully used as a piezoresistive sensor to detect human motions (such as fingers/wrists/elbows/knees movement), and GP/CMF-NR composite sponge also can be used as a collision warning sensor to warn the collision in a moment and protect the things from damage at some extent. More importantly, when being attacked by fires, GP/CMF-NR sponge also can be used as a fire-warning sensor with the sensitive fire-warning response time, which triggered a fire-warning lamp within 1.2 s. This investigation provides a convenient and environmentally friendly strategy for fabricating conductive natur rubber sponges and has promising applications in the field of piezoresistive sensors and fire-warning sensors.

Soft Liquid Metal Infused Conductive Sponges

AbstractLiquid metal droplets of gallium (Ga) and Ga‐based alloys are traditionally incorporated as deformable additives into soft elastomers to make them conductive. However, such a strategy has not been implemented to develop conductive sponges with real sponge‐like characteristics. Herein, polyurethane‐based sponges with Ga microdroplets embedded inside the polyurethane walls are developed. The liquid phase (at 45 °C) and solid phase (at room temperature) transition of the Ga fillers shows the temperature‐dependent functional variations in the mechanical, thermal, and electrical properties on the prepared composite sponges, which are investigated in detail. Unlike elastomers, the sponge possesses excellent elastic recovery, at ≈90%, and conductivity durability without sacrificing structural integrity. The reversible change of resistivity range is remarkable. When the Ga fillers account for 18% of the total sponge volume, the electrical resistivity varies from infinite values (insulator) under no applied pressure to 39.0 Ω m for the solid phase and 3.8 Ω m for the liquid phase under 386.8 kPa. New opportunities in developing flexible electrically conductive composite sponges with tunable mechanical and electrical properties that can be implemented for a variety of future applications are proposed.

Elastic response of polymer-nanoparticle composite sponges: Microscopic model for large deformations

We propose a minimalist coarse-grained microscopic model to investigate the mechanical response of ice-templated polymer nanocomposite sponges with large open voids. Earlier experimental work [Rajamanickam et al., Chem. Mater. 26, 5161 (2014)] has demonstrated that such systems show elastic recovery after being subjected to large compressive strains exceeding $80%$, despite being comprised primarily of inorganic nanoparticles. Our model captures the essential features of the nonlinear mechanical response to uniaxial compression up to strain $\ensuremath{\gamma}=0.8$. From our simulation we identify three different regimes for the stress response: (i) the stress increases linearly with strain at low strains up to $\ensuremath{\approx}0.2$; (ii) at intermediate strains, such that $\ensuremath{\gamma}$ is approximately in the range $0.2\ensuremath{-}0.5$, we observe a plateau regime in the stress-strain data; and (iii) finally we see a sharp increase in stress at strains $>0.5$. This agrees with experimental observations. The model helps us establish a correlation between the stress-strain response and the underlying microscopic reorganization of microstructure spanning multiple length scales, which leads to the emergence of the three regimes. The nature of individual void deformations was statistically analysed to demonstrate the progression of void shapes as the sponge is compressed. We also establish that nanoparticles at the interface of voids respond differently to stress as compared to those away from the interface. Our simulation model is versatile and allows us to vary parameters, which correspond to variations in the cross-link density and architecture of nanoparticle connectivity in experiments.

Bletilla striata polysaccharide modified collagen fiber composite sponge with rapid hemostasis function

Emergencies often result in uncontrollable bleeding, which is thought to be the leading cause of death at the scene of the injured. Among various hemostasis scenarios, collagen fiber (CF) is gradually replacing traditional hemostatic materials due to its superior properties and ease of sourcing from animals. Herein, we use CF and the natural herbaceous Bletilla striata as raw materials to prepare a collagen fiber-oxidized Bletilla striata composite hemostatic sponge (CFOB). During the cross-linking process, the triple helix structure of collagen stays intact, and its porous three-dimensional network structure brings excellent bulkiness and water absorption properties. Experiments show that the optimal amount of sponge CFOB-10, namely oxidized Bletilla striata polysaccharide 0.5 mg/mL and CF 5 mg/mL, only needed 25 ± 4.06 s for hemostasis time in the rat liver hemorrhage model. In addition, CFOB meets the safety performance requirements of cytotoxicity classification standard 0. Therefore, the optimal amount of CFOB is an excellent new hemostatic material with application potential.Graphical

Porous polydimethylsiloxane composite filled with graphene oxide and gold nanoparticles produced by laser ablation in liquids

The design of new materials with improved mechanical and biological properties is a major interest in biomedical applications. This paper presents the synthesis of macro-porous polydimethylsiloxane (PDMS) sponge composites as potential materials for tissue engineering. PDMS sponge with pores size ranging between 50 and 900 μm was produced using the sugar templating process. The sponges were decorated with graphene oxide and gold nanoparticles created by the laser ablation in liquid and then they were morphologically, mechanically and biologically characterized. The optical properties of all the solutions containing nanoparticles were studied with the UV-ViS spectroscopy. The biological behaviour and performance of native PDMS, PDMS decorated with graphene oxide, and with graphene oxide and gold nanoparticles were compared. Results show that the composites and equally as important the adopted processing are both biocompatible. The quality of filler dispersion in the porous composites was observed by scanning electron (SEM) and atomic force (AFM) microscopies. The biocompatibility of the composites and of the preparation procedure was confirmed by monitoring the cytotoxicity of the composites for different types of cell cultures.

Multifunctional and durable graphene-based composite sponge doped with antimonene nanosheets

The development of flexible multifunctional composites is an important topic in the fields of materials engineering, electronics, aerospace and biomedicine. However, there are still major challenges to achieve a variety of functions to meet the requirement for the application. Herein, a flexible multifunctional porous composite is successfully prepared by fabricating both modified graphene and antimonene into a melamine sponge. Compared with the graphene composite sponge, the addition of antimonene improved its electrochemical and sensing performances. The specific capacitance of antimonene/graphene composite sponge was significantly increased, while the capacitance retention rate was 83% under 20,000 charge–discharge cycles. The pressure sensitivity of the prepared flexible multifunctional device assembled was 44% higher than that of the graphene composite sponge. A power supply-integrated sensing system was assembled for monitoring human motion signals. The experimental results show that this system is a promising monitoring device with broad potentials in the fields of biosensing.

Polyvinyl alcohol/sodium alginate composite sponge with 3D ordered/disordered porous structure for rapidly controlling noncompressible hemorrhage

It is still a challenge to develop a sponge that can efficiently control noncompressible bleeding to meet the emergency treatment and clinical demand. Herein, we combined the 3D printing sacrificial template method and freeze-drying technology to prepare polyvinyl alcohol/sodium alginate (PVA/SA) composite sponges with ordered microchannels and disordered porous structure. Compared with conventional sponges, the prepared sponge showed ultra-rapid water/blood absorption capacity and satisfactory mechanical properties. Furthermore, when the sponge was stuffed into a noncompressible wound and contacted with blood, it could accurately guide and quickly absorb a large amount of blood through the microchannels. Moreover, the platelets, red blood cells and coagulation factors would be enriched in the microchannels and microporous structure.In the SD rat liver noncompressible hemorrhage and femoral artery puncture injury model, PVA-SA composite sponge with 3D ordered/disordered porous structure showed enhanced hemostatic performance compared with commercial MPVA sponges. Depend on the special ordered/disordered porous structure, PVA-SA composite sponge could accelerate the blood convergence and promote coagulation. This design of special porous structure opened up a new avenue to develop hemostatic sponges for rapidly controlling noncompressible hemorrhage.

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.

Superelastic Clay/Silicone Composite Sponges and Their Applications for Oil/Water Separation and Solar Interfacial Evaporation.

3D porous materials are of great interest in many areas of study, but it is still difficult to prepare those with high elasticity and low thermal conductivity via facile methods. Here, superelastic laponite/silicone (LS) composite sponges with low thermal conductivity are prepared via a simple approach. The LS sponges were analyzed by various characterization methods. The content of laponite nanosheets in LS sponges has a great influence on the microstructure, comprehensive mechanical properties, and thermal conductivity. LS sponges feature (i) high mechanical strength, compressibility, and elasticity, (ii) excellent superhydrophobicity/superoleophilicity, and (iii) low thermal conductivity. Consequently, LS sponges could be used for water purification, for example, oil/water separation and solar-driven interfacial evaporation in combination with carbon nanotubes (CNTs). The LS/CNTs solar evaporator has a remarkable evaporation rate of 1.77 kg m-2 h-1 for the 3.5 wt % NaCl aqueous solution under 1 kW m-2 irradiation and high salt resistance. We foresee that this study will promote the development of new 3D porous materials and their applications.

Rapid hemostasis and excellent antibacterial cerium-containing mesoporous bioactive glass/chitosan composite sponge for hemostatic material

Rapid and effective hemostasis is key to controlling bleeding and reducing mortality. Here, a composite hemostatic sponge (Ce-MBG/CHT) of cerium-containing mesoporous bioactive glass (Ce-MBG) and chitosan (CHT) was prepared by a freeze-drying technique and compared with the commercially available gelatin sponge (GS), to further evaluate the hemostatic performance of composite sponge materials. The results indicate that the pore structure, porosity, and water absorption of the sponge improved following the addition of Ce-MBG. Whole blood coagulation studies suggested that Ce-MBG/CHT has superior hemostatic properties to GS and validated in vitro thrombosis, platelet adhesion and blood compatibility. In vitro coagulation studies showed that factor XII was activated by the addition of Ce-MBG, inducing the intrinsic coagulation pathway. Furthermore, we evaluated the cytocompatibility of samples after contact with L929 cells for 24, 48, and 72 h via the cytotoxicity test. Compared with GS, 4Ce-MBG/CHT was more efficient against E. coli and S. aureus. All these results indicate that Ce-MBG/CHT sponges are likely useful for rapid hemostasis.

Pectin/poly(vinylpyrrolidone) composite sponges as wound dressings for delivery of silver sulfadiazine

Pectin/poly(vinylpyrrolidone) composite sponges as wound dressings for delivery of silver sulfadiazine

Tough, Eco-Friendly and Superhydrophobic Sio2-Polyvinyl Alcohol Composite Sponge for Durable Oil Remediation

Tough, Eco-Friendly and Superhydrophobic Sio2-Polyvinyl Alcohol Composite Sponge for Durable Oil Remediation

Polyvinyl Alcohol Formaldehyde Three-Dimensional Composite Sponges with Hierarchical Pore Structure for W/O Emulsion Separation

Polyvinyl Alcohol Formaldehyde Three-Dimensional Composite Sponges with Hierarchical Pore Structure for W/O Emulsion Separation

Graphene/Electrospun Carbon Nanofiber Sponge Composites Induced by Magnetic Particles for Mutil-Functional Pressure Sensor

Graphene/Electrospun Carbon Nanofiber Sponge Composites Induced by Magnetic Particles for Mutil-Functional Pressure Sensor