Porous Sponge Research Articles

Multi-Dimensionally Functionalized Pressure Sensor for Human Motion Detection Based on 1D AgNWs/2D rGO-Coated 3D Porous Sponge

Multi-Dimensionally Functionalized Pressure Sensor for Human Motion Detection Based on 1D AgNWs/2D rGO-Coated 3D Porous Sponge

A natural carboxylated sisal fiber/chitosan/kaolin porous sponge for rapid and effective hemostasis

A natural carboxylated sisal fiber/chitosan/kaolin porous sponge for rapid and effective hemostasis

Effect of hyaluronic acid on the formation of acellular dermal matrix-based interpenetrating network sponge scaffolds for accelerating diabetic wound healing through photothermal warm bath

Adequate vascularization essential for delivering nutrients critical to wound healing, yet impaired angiogenesis is a major barrier in diabetic wound repair. This study investigates the impact of hyaluronic acid on interpenetrating network sponge scaffolds derived from an acellular dermal matrix, with the aim of enhancing vascularization and healing of diabetic wounds via photothermal warm bath therapy. We prepared three-dimensional porous sponges (H1P4D2@DFO) using molecular interpenetration and ion crosslinking of porcine acellular dermal matrix (PADM), hyaluronic acid, and polydopamine nanoparticles loaded with deferoxamine mesylate (PDA@DFO). This resulting extracellular matrix-based sponge demonstrated properties suitable for wound repair, including high cell adhesion, biocompatibility, bioactivity, porosity (85 %), and water absorption (4500 %). The near-infrared (NIR) photothermal effect of PDA@DFO and the sustained release of deferoxamine mesylate (DFO) enhanced wound vascularization within the wound site. These findings suggest that our sponge scaffold can simulate skin-like structures and establish a supportive microenvironment conducive to microvascular reconstruction. By combining the photothermal warm bath approach with the scaffold's tailored 3D structure, we observed enhanced angiogenesis and accelerated diabetic wound healing, indicating potential clinical applications of these scaffolds in chronic wound management.

A Rootless Duckweed-Inspired Flexible Artificial Leaf from Plasmonic Photocatalysts.

The naturally existing leaves are ubiquitous two-dimensional flexible solar-to-chemical conversion systems that can run continuously in a sustainable manner. However, the current artificial photocatalytic systems are unable to achieve this due to the grand challenge in integrating existing photocatalysts in a flexible layout with high conversion efficiency and the ability to function independently. Here, we report on a rootless duckweed-inspired artificial leaf based on a lightweight, flexible, Janus plasmonic nanosheet-integrated sponge. The Janus plasmonic catalytically active nanosheet was made from self-assembled gold nanocube nanoassemblies grown on the porous sponges, which were further coated with an ultrathin palladium layer on one side via a ligand symmetry-breaking method. This sponge-based photocatalytic system is lightweight yet able to float on a water surface and conducts the gas-liquid reaction without auxiliary pumping and mixing devices. In a model reaction of 4-nitrophenol reduction, this floating leaf could achieve 2.5-fold and 65-fold higher efficiency than the corresponding dispersion and precipitation systems, respectively. The film theory is used to explain the sponge-based lightweight solar-to-chemical conversion system in a detailed kinetic and thermodynamic analysis, including the reaction rate constant, activation energy, enthalpy, entropy, Gibbs energy, and equilibrium constant.

A low-carbon dual-functional evaporator with photothermal and catalytic properties for enhanced VOCs removal during water evaporation

Solar interface distillation technologies are widely used for seawater desalination, wastewater treatment, and clean water production. However, during evaporation, volatile organic compounds (VOCs) in the water often evaporate coincidently with the water vapor, presenting a major pollutant challenge. Combining solar evaporation with advanced oxidation processes (AOP) is a potential solution for simultaneous water purification and VOC degradation. Herein, a dual-functional sponge photothermal evaporator (MBC-SA/MS) was designed to assess the efficacy of this approach. A simple porous sponge embedded with a composite catalyst, comprising MoO3−x, BiOCl, and CNT, was able to demonstrate simultaneous photothermal evaporation and catalytic degradation. MBC-SA/MS exhibited exceptional photothermal conversion efficiency and robust catalytic activity, achieving an evaporation rate of 2.1 kg m−2 h−1 under 1.0 sun intensity. Effective mitigating of phenol emissions was observed through persulfate activation resulting in 90 % phenol degradation. Life cycle assessment (LCA) confirmed this evaporator system had low environmental impact and was sustainable. This research presents a new compelling strategy for tackling VOC pollution and simultaneously enhancing water purification via solar interfacial evaporation.

Porous g-C3N4 tubes in-situ anchored by waste biomass-derived carbon dots for photocatalytic reduction of sunset yellow and Escherichia coli in juice

Chemical hazardous substances and hazardous pathogenic bacteria pose a serious risk to human health. The development of efficient, safe and simple removal technologies is urgent. In this study, waste biomass derived carbon dots in-situ anchored porous g-C3N4 tubes were prepared by supramolecular self-assembly method. The prepared photocatalyst exhibited enhanced light absorption, large surface area, and abundant reactive sites. Photoelectrochemical analyses confirmed that the introduction of CDs could effectively promote the separation and transfer of photogenerated carriers with enhanced degradation of sunset yellow (95.4 %) and inactivation of Escherichia coli (98.3 %) under visible light. Furthermore, the development of g-C3N4 loaded floatable porous alginate sponges for the simultaneous removal of E. coli and sunset yellow from fruit juices, obtaining efficient purification results and satisfactory overall acceptability. This work provides a feasible pathway for photocatalytic decontamination of contaminated liquid food.

Tailoring of Polypyrrole Wrapped Cotton Fiber Sponge for Simultaneous Solar Steam and Solar Thermoelectric Generation

AbstractSolar steam generation (SSG) using floatable evaporators to absorb solar energy and generate heat at the water–air interface has attracted increasing interest in achieving water purification and desalination. Using biodegradable and porous biomass materials as evaporators to fabricate high‐performance SSG devices is a promising route, but the poor efficiency and fussy and energy‐intensive manufacturing process for biomass material‐based evaporators will restrict their practical application. Here, an old commercial cotton quilt is used to prepare porous cotton fiber sponges (CFS) via a simple and scalable mechanical foaming strategy. After being decorated by the polypyrrole (PPy), the CFS@PPy sponge with a hierarchical porous structure shows broadband light absorption capacity, good hydrophilicity, and excellent photothermal capacity. The obtained sponge can be directly used as an evaporator floating on the seawater and shows a high steam‐generation efficiency of 85.07% under 1 sun irradiation. Additionally, it can be used as a photothermal material to construct a solar thermoelectric generation (STG) device and achieve an enhanced open‐circuit voltage (Vout) of 0.4 V and output current (Iout) of ≈59.6 mA under 5 sun irradiations. With the help of a boost converter, the power generation from the STG device can continuously charge the electric bulb and wristband.

Superhydrophobic/superoleophilic polyurethane /reduced graphene oxide/ sponge for efficient oil-water separation and photothermal remediation

Due to the rapid development of global industrialization, the frequent occurrence of organic matter leakage and oil leakage accidents has led to increasingly serious environmental pollution. Therefore, this paper has proposed a facile and affordable method for creating oil water separation materials, and successful creating a super hydrophobic/super oleophilic functional porous polyurethane sponge modified by reduced graphene oxide and polydopamine (PDA-rGO-PU). Dopamine undergoes a self-polymerization event that creates polydopamine, which is subsequently coated on a polyurethane framework to create a sponge structure with several active sites. The surface of the modified sponge structure was coated with graphene oxide by a simple drop-coating method, and graphene oxide coated on the surface of polydopamine was reduced to create the superhydrophobic/superoleophilic material. The PDA-rGO-PU demonstrated strong anti-adhesion properties and a high oil-water separation efficiency of 99.8 % while having high water contact angles of 155 ° ± 3 ° and oil contact angles (OCA) of 0 °. It has a strong ability to adsorb various oils and organic solvents, the excellent photothermal effect allows PDA-rGO-PU to raise temperature by 37.9 % in the presence of light. PDA-rGO-PU has good continuous oil sorption performance after installing the pump. When under simulated lighting conditions, the sorption time of modified sponge on crude oil was shortened by 2.3 times.

Developing a multifunctional chitosan composite sponge for managing traumatic injuries

Developing porous hemostatic sponges that are both biosafe and multifunctional remains a complex challenge. Conventional hemostatic techniques often fall short in managing bleeding effectively, leading to severe critical cases such as suboptimal hemostasis, increased infection risk, and complications arising from profuse bleeding. To address these deficits, our study introduces a novel multifunctional nanocomposite sponge that synergistically incorporates chitosan (CS), cellulose (Cel), graphene oxide (GO), and silver (Ag) nanoparticles. The resulting CS/Cel/GO/Ag developed demonstrates a swelling rate exceeding 3000 %, an absorption rate of over 2100 %, and the lowest stress surpassing 20 kPa at an initial 80 % strain. In vitro analyses reveal that the CS/Cel/GO/Ag sponge has excellent cytocompatibility, non-hemolytic nature, and competence in blood cell adherence and bacterial inhibition. In vivo evaluations further demonstrate that compared to conventional hemostatic methods, the sponge substantially enhances hemostatic efficacy, as evidenced by the marked reductions in clotting times and diminished blood loss compared to conventional hemostatic methods. Specifically, the test results of the CS/Cel/GO/Ag sponge across three different models are as follows: for the rat tail amputation model, the clotting time was 99 s, while blood loss was 222 mg; for the rat liver injury model, the clotting time was 129 s. while blood loss was 812 mg; for the rat femoral artery laceration model, the clotting time was 96 s, while blood loss was 758 mg. The compelling attributes of the CS/Cel/GO/Ag sponges position them as a promising solution for the acute management of bleeding. Their excellent performance indicates they have potential role to play in trauma care.

Preparation and Characterization of Demineralized Bone Extracellular Matrix/Chitosan Porous Microcarriers

Composite porous microcarriers based on demineralized bone extracellular matrix (DBECM) and chitosan (Cs) were prepared using a combined emulsion and freeze-drying method. The effects of digestion by pepsin on the DBECM properties were investigated. The morphologies and porous structure of the DBECM/Cs porous microcarriers were observed by using a scanning electron microscope (SEM). The cytocompatibility of the DBECM/Cs porous microcarriers were studied by using cell counting kit-8 (CCK-8) and calcein acetoxymethyl ester/propidium iodide (CAM/PI). DBECM was digested into small pieces with a loose porous sponge structure and the digested DBECM showed an amorphous state. The resultant DBECM/Cs porous microcarriers showed a spherical shape and an interconnective porous structure. The CCK-8 and CAM/PI analyses indicated that the DBECM/Cs porous microcarriers were non-cytotoxic and showed good biocompatibility, providing a more favorable growth environment for cells.

Under Water Superelastic Porous Nanofibrous Sponge for Efficient RNA Separation and Purification.

Developing monolithic materials for chromatography columns with a novel interconnected porous structure is vital for the enhancement of the separation efficiency of RNA purification processes. Herein, a porous nanofibrous sponge (PNFS) is constructed by freeze molding and freeze-drying a nanofiber dispersion with ethylene vinyl alcohol copolymer nanofibers as the skeleton, chitosan (CS) and polyethylenimine (PEI) as the binders, and glutaraldehyde (GA) as the crosslinking agent. The results show that when the CS content of the dispersion is 1.5 wt %, PNFS demonstrates a high static adsorption capacity of 406.5 mg/g (30.7 mg/m2) and a dynamic adsorption capacity of 382.6 mg/g (28.9 mg/m2) at a flow rate of 1 mm/min. Moreover, PNFS shows a high specific adsorption performance toward RNA in the presence of bovine serum albumin, lecithin, or DNA by adjusting the solution pH value and the method of gradient elution. Besides, PNFS presents exceptional performance in the rapid separation of RNA from HT22 cells without degradation. This result can be attributed to optimized morphology, pore structure, and comprehensive performance of PNFS, benefiting from the synergistic effect of the highly oriented porous structure and CS-PEI interaction derived from the high-density adsorption ligands on the channel walls of PNFS. This work provided an efficient strategy to handle the permeability/adsorptivity trade-off for ion-exchange chromatographic materials.

Electrically conductive polyaniline: Graphite composite on porous polyurethane sponge with enhanced sensitivity of humidity

AbstractRecent advancements in organic materials based sensor technology created a prospective field in designing sensors that are both cost‐effective and environment friendly. In view of that an electronic material system has been prepared depositing a uniform layer of graphite‐infused Polyaniline (PANI) onto the sponge framework using a straightforward physical vapor deposition technique. The prepared active materials were studied for the composition, morphology, optical properties, and charge transport characteristics. In the current context of rapidly growing sensor technology, this works describes an innovative approach of improving the response of the prepared electronic system of PANI/Gr composites, integrated into porous PU sponge substrates. Incorporation of graphite in PANI improved the electrical conductivity of the composite and porous structure of PU increased the interaction surface area. The performance of the prepared materials in humidity detection was evaluated by studying their resistive response under varying humidity levels, which was measured through current‐voltage (I‐V) characteristics. The higher interaction sites of the reported active sensing system leads to inspiring humidity sensitivity of 0.522–26.22 kΩ/% RH with reasonable response and recovery time of 572 and 416 sec respectively. Additionally, the reported sensor system consisting of degradable materials will offer a useful way of reducing electronic garbage.

High-Performance Flexible Sensor with Sensitive Strain/Magnetic Dual-Mode Sensing Characteristics Based on Sodium Alginate and Carboxymethyl Cellulose.

Flexible sensors can measure various stimuli owing to their exceptional flexibility, stretchability, and electrical properties. However, the integration of multiple stimuli into a single sensor for measurement is challenging. To address this issue, the sensor developed in this study utilizes the natural biopolymers sodium alginate and carboxymethyl cellulose to construct a dual interpenetrating network, This results in a flexible porous sponge that exhibits a dual-modal response to strain and magnetic stimulation. The dual-mode flexible sensor achieved a maximum tensile strength of 429 kPa and elongation at break of 24.7%. It also exhibited rapid response times and reliable stability under both strain and magnetic stimuli. The porous foam sensor is intended for use as a wearable electronic device for monitoring joint movements of the body. It provides a swift and stable sensing response to mechanical stimuli arising from joint activities, such as stretching, compression, and bending. Furthermore, the sensor generates opposing response signals to strain and magnetic stimulation, enabling real-time decoupling of different stimuli. This study employed a simple and environmentally friendly manufacturing method for the dual-modal flexible sensor. Because of its remarkable performance, it has significant potential for application in smart wearable electronics and artificial electroskins.

Multilayer polyelectrolyte and palladium nanoparticle decorated porous materials as fixed-bed reactors for efficient reduction of 4-NP

In this study, a continuous flow catalytic reactor based on three-dimensional porous sponge bed with the uniform distribution of catalyst to treat 4-NP wastewater efficiently. The porous sponge is used as a support to construct polyelectrolyte multilayers by loading dopamine. And the multilayer polyelectrolyte is closely bound to dopamine to form polyelectrolyte film, and the nanocatalysts are synthesized by electrostatic adsorption of precursors. The reactor realizes the uniform and stable distribution of the catalyst in the three-dimensional porous sponge, and the reactant transfers from bulk solution to catalyst surface by the way of convection and diffusion, which enhances mass transfer and further improves the reaction efficiency. Under the operating conditions of a catalytic bed as small as 3 cm, a 4-NP concentration up to 4.5 mM, and a flow rate of 300 μL min−1, the conversion rate remained above 96 % for up to 200 h, indicating that the reactor has good catalytic efficiency. The results showed that this continuous flow catalytic system structure has excellent performance in wastewater treatment.

Preparation of Magnetic Spongy Porous Carbon Skeleton Materials for Efficient Removal of BTEX.

Magnetic polymer microspheres have been extensively utilized as separable and highly efficient adsorbents in wastewater treatment. In this study, a series of novel magnetic spongy porous carbon skeleton materials (Mag-SPCS) have been designed and synthesized by acetonitrile suspension precipitation polymerization, which combines the advantages of the acetonitrile precipitation method and the suspension polymerization method. It was demonstrated that the transformation of the material morphology from microspheres to a porous sponge was achieved by a gradual decrease in the usage amount of ethylene glycol. After N,N-dimethyloctadecylamine (C18) was grafted onto the Mag-SPCS materials, the C18-Mag-SPCS materials with a superhigh saturation adsorption capacity and superfast adsorption efficiency were used for the removal of BTEX (toluene, benzene, and para-xylene) in wastewater. Subsequently, the adsorption properties of the composites with different morphologies were evaluated, and the effect of the usage amount of C18 on the adsorption properties of the C18-Mag-SPCS was further investigated. The maximum adsorption capacities of C18-Mag-SPCS for benzene, toluene, and para-xylene were 714.84, 564.32, and 394.48 mg/g, respectively. The adsorption process was conducted in accordance with the proposed secondary and Langmuir models. Finally, the FTIR, XPS, and XRD characterization results before and after adsorption demonstrated that the adsorption mechanism of toluene onto C18-Mag-SPCS was primarily hydrogen bonding, π-π stacking, and van der Waals forces. These findings of the study indicate that the composite material exhibits an ultrahigh saturation adsorption capacity and ultrafast adsorption efficiency, thereby confirming its considerable potential for application in wastewater treatment.

Electromechanically stable and flexible poro-hyperelastic composites for multimodal robotic tactile sensing

The expansion of automated production places increased demands on intelligent sensory networks for collecting and processing various input signals, which necessitate higher standards for multimodal detection, sensitivity, and sensing response speed. Here, this work developed a poro-hyperelastic composites-based multimodal tactile sensor capable of triboelectric, piezoresistive, and capacitive modes across multiple strains and frequency domains. Such the multilayered flexible multimodal mechano-electronic sensor (MMES) is constructed from a carbon nanotubes porous sponge (CNPS), facilitating switching between trimodal sensing modes integrated within a single sensor structure, effectively enhancing the electromechanical robustness of the sensory system. The present MMES sensor exhibits excellent pressure sensing performances, with a wide range (0–20 kPa), fast response (less than 102 ms in piezoresistive mode and less than 62 ms in capacitive mode), high sensitivity (up to 0.12 V/kPa⁻1 in triboelectric mode), and long-term durability (exceeding 10,000 cycles). Moreover, a micro-CT generated 3D model was established using finite element analysis (FEA) to investigate porous hyperelastic behaviours of the CNPS composites, in agreement with experimental data. The results demonstrated that the MMES sensor is particularly suitable for dynamic feedback in robotic arms, allowing production lines to make accurate distinguishments and operations by sensing distinct materials and resistances encountered during assembly in real time. The outcomes offer promising applications of multimodal robotic tactile sensing for human-machine interaction.

Multifunctional Chitosan Nanofiber-Based Sponge Materials Using Freeze-Thaw and Post-Cross-Linking Method.

The fabrication of porous sponge materials with stable structures via cross-linking diverse polymers presents significant challenges due to the simultaneous requirements for phase separation as a pore-forming step and cross-linking reactions during the fabrication process. To address these challenges, we developed a sponge material solely from natural-based polymers, specifically chitosan nanofibers (CSNFs) and dialdehyde carboxymethyl cellulose (DACMC), employing a straightforward, eco-friendly technique. This technique integrates a facile freeze-thaw method with subsequent cross-linking between CSNFs and DACMC. This method effectively addresses the difficulties associated with pore formation in materials, which typically arise from the rapid formation and precipitation of polyionic complexes during the mixing of anionic and cationic polymers, using ice crystals as a rigid template. The resultant sponge materials exhibit remarkable shape recoverability in their wet state and maintain light, stable porosity in the dry state. Furthermore, in comparison to commonly used commercial foams, this composite porous material demonstrates superior fire retardancy and thermal insulation properties in its dry state. Additionally, it shows effective adsorption capacities for both cationic and anionic dyes and metal ions. This method of using biobased polymers to produce porous composites offers a promising avenue for creating multifunctional materials, with potential applications across various industries.

Synthesis of nitrogen enriched porous carbon sponge with the assistance of hard template and physical activation for highly efficient CO2 adsorption

Porous carbons are attractive materials for CO2 capture due to their unique properties. In the current work, N-doped porous carbon sponge (NDPCS) was synthesized with a combined hard template and CO2 activation method, and the applications in CO2 adsorption were also studied. Correlations between synthesis parameters and the product’s morphology were revealed, and effects of the activation conditions on N content and textural properties were analyzed. CO2 adsorption performances of the NDPCS were also thoroughly investigated. The influences of various physicochemical properties on adsorption properties were discussed. CO2 uptake at 25 °C and 1 bar was relatively low (2.16–2.50 mmol/g). However, NDPCS-3–3 showed impressively high adsorption efficiency of 1.63 (mmol/g)/(100 m2/g), much better than some of the best performing samples from reported works. The superior performances were attributed to the combined effects of abundant ultramicropores and enriched N-doping. The current work showed that the NDPCS had great potential for applications in CO2 capture.

Evaluation of acoustic environmental effects and improvement method of ecological fish-nest bricks in the Yangtze River Basin: A model-based case study

With the rapid development of the Yangtze River Basin, the issue of underwater noise pollution has become increasingly severe, which has adversely affected aquatic creatures, particularly fish. Ecological fish-nest bricks (EFNBs), a new type of eco-friendly revetment, can provide a favorable habitat for fish. However, its effects on the acoustic environment remain unclear. The finite element numerical simulation method of acoustic-structure coupling is adopted to explore the acoustic environment of EFNBs, analyzing the impact of sound source frequency (within 300 Hz), structural forms, and arrangement of these bricks on the internal sound pressure level. The sound pressure level distribution of A-EFNBs were also analyzed at a distance of 0–0.5 m from the opening. A method of acoustic environment improvement is proposed, which utilizes porous polyurethane sponge (PPS) sound-absorbing material to establish a conducive acoustic environment for fish in EFNBs. The study results indicate that at low frequencies of sound source (f ≤ 150 Hz), the sound pressure level within EFNBs slightly decreases compared to the adjacent areas without EFNBs. The sound pressure level variation within the bricks increases with sound source frequency. The peak sound pressure increases with the number of openings. Interval arrangements can in general decrease sound pressure by less than 20 dB. At higher frequencies(f＞200 Hz), the sound pressure level at the opening of the A-EFNBs tends to increase. However, the PPS sound-absorbing material substantially reduces the sound pressure level by 15 –55 dB, rendering it an effective method for improving the acoustic environment for fish. The PPS sound-absorbing material is more suitable for habitat improvement of black carp (Mylopharyngodon piceus) and grass carp (Ctenopharyngodon idellus) with relatively low hearing thresholds among the four famous Chinese carps. The research findings can serve as a reference for designing and implementing river ecological restoration projects.

Hybrid amphiphilic janus PDMS sponge enabling electrical sensing of organic solvents

Porous materials exhibit exceptional suitability for underwater pollutant purification through selective absorption of water and oil. However, most reported porous materials designed for oil absorption, removal, and reuse lack the selectivity necessary to distinguish between different types of organic solvents. In this study, a sponge-based sensor that is responsive to and capable of distinguishing changes in resistance induced by physical deformation of the conductive layer is presented. The sensor is a Janus-structured porous PDMS sponge fabricated using sugar cube templates. The solvent-absorbing section features 300 µm pores to maximize absorption relative to its volume. The resistance-sensing section was created with 600 µm pores and PDMS mixed with the surfactant Triton X-100 (TX-100) to enhance hydrophilicity, allowing for low-cost dip coating with a water-dispersible conductive polymer poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS). Detecting the physical changes in the PEDOT:PSS film on the sponge surface allowed distinguishing responses to physical stimuli. Analyzing the trends in resistance changes under physical stimuli and in polar/nonpolar solvents, conductivity change mechanisms are proposed. The type of organic solvent absorbed by the sponge can be differentiated using these mechanisms.