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1.
Int J Biol Macromol ; 268(Pt 2): 131945, 2024 May.
Article in English | MEDLINE | ID: mdl-38685544

ABSTRACT

Hydroxypropyl cellulose (HPC) is a green thermochromic material in energy-saving buildings, anti-counterfeiting, and data security fields. However, the high lower critical solution temperature (LCST) of HPC, around 42 °C (higher than the human thermal comfort temperature), limits its thermochromic sensitivity, poor stability, and short lifespan. Herein, we developed a durable, high-performance cellulose-based thermochromic composite with a lower LCST and easy preparation capability by combining HPC with sodium carboxymethyl cellulose (CMC). In such thermochromic cellulose, CMC constructs a hydrophilic skeleton to enable uniform dispersion of HPC, and functions as a stronger competitor to attract the water molecules compared to HPC, both of which trigger high thermochromic sensitivity and low LCST (just 32.5 °C) of our CMC/HPC. In addition, CMC/HPC shows superior stability, such as 100-day working capability and 60-time recyclability. This advancement marks a significant step forward in creating sustainable, efficient thermochromic materials, offering new opportunities for energy conservation in the building.


Subject(s)
Carboxymethylcellulose Sodium , Cellulose , Temperature , Carboxymethylcellulose Sodium/chemistry , Cellulose/chemistry , Cellulose/analogs & derivatives , Hydrophobic and Hydrophilic Interactions
2.
Adv Healthc Mater ; 13(13): e2304676, 2024 May.
Article in English | MEDLINE | ID: mdl-38294131

ABSTRACT

Adhesive hydrogel holds huge potential in biomedical applications, such as hemostasis and emergent wound management during outpatient treatment or surgery. However, most adhesive hydrogels underperform to offer robust adhesions on the wet tissue, increasing the risk of hemorrhage and reducing the fault tolerance of surgery. To address this issue, this work develops a polysaccharide-based bioadhesive hydrogel tape (ACAN) consisting of dual cross-linking of allyl cellulose (AC) and carboxymethyl chitosan (CMCS). The hygroscopicity of AC and CMCS networks enables ACAN to remove interfacial water from the tissue surface and initializes a physical cross-link instantly. Subsequently, covalent cross-links are developed with amine moieties to sustain long-term and robust adhesion. The dual cross-linked ACAN also has good cytocompatibility with controllable mechanical properties matching to the tissue, where the addition of CMCS provides remarkable antibacterial properties and hemostatic capability. Moreover, compared with commercially available 3 M film, ACAN provides an ultrafast wound healing on tissue. The ACAN hybrid hydrogels have advantages such as biocompatibility and antibacterial, hemostatic, and wound healing properties, shedding new light on first-aid tape design and advancing the cellulose-based materials technology for high-performance biomedical applications.


Subject(s)
Cellulose , Chitosan , Hydrogels , Wound Healing , Chitosan/chemistry , Chitosan/analogs & derivatives , Cellulose/chemistry , Cellulose/analogs & derivatives , Cellulose/pharmacology , Hydrogels/chemistry , Hydrogels/pharmacology , Wound Healing/drug effects , Animals , Mice , Anti-Bacterial Agents/chemistry , Anti-Bacterial Agents/pharmacology , Biocompatible Materials/chemistry , Biocompatible Materials/pharmacology , Cross-Linking Reagents/chemistry , Hemostatics/chemistry , Hemostatics/pharmacology , Humans
3.
Int J Biol Macromol ; 258(Pt 2): 129107, 2024 Feb.
Article in English | MEDLINE | ID: mdl-38159705

ABSTRACT

A large number of polluting substances, including chlorinated organic substances that were highly stable and hazardous, has been emitted due to the rapidly developing chemical industry, which will affect the ecological environment. Nanocellulose aerogels are effective carriers for adsorption of oil substances and organic solvents, however, the extremely strong hydrophilicity and poor mechanical properties limited their widespread applications. In this study, TEMPO-oxidized cellulose nanofibrils was modified with 2, 4-toluene diisocyanate (TDI) and 4,4'-diphenylmethane diisocyanate (MDI) to prepare strong and hydrophobic aerogels for oil adsorption. The main purpose was to evaluate and compare the effects of two diisocyanates on various properties of modified aerogels. It was found that the modified aerogel had better hydrophobic properties, mechanical properties and adsorption properties. In particular, the modified aerogel with TDI as crosslinker showed a better performance, with a maximum chloroform adsorption capacity of 99.3 g/g, a maximum water contact angle of 131.3°, and a maximum compression stress of 36.3 kPa. This study provides further evidence of the potential of functional nanocellulose aerogel in addressing environmental pollution caused by industrial emissions.


Subject(s)
Cellulose , Toluene 2,4-Diisocyanate , Cellulose/chemistry , Hydrophobic and Hydrophilic Interactions , Adsorption , Solvents/chemistry , Water/chemistry
4.
Carbohydr Polym ; 314: 120948, 2023 Aug 15.
Article in English | MEDLINE | ID: mdl-37173049

ABSTRACT

Passive daytime radiative cooling (PDRC) materials simultaneously featuring aesthetic and safety distinctions demonstrate versatile applications beyond cooling buildings, while the integrated advantages of high strength, morphological reconfigurability, and sustainability remain challenging for the conventional PDRC materials. Herein, we designed a robust, custom-shaped and eco-friendly cooler via a scalable solution-processable strategy, involving the nano-scale assembly of nano cellulose (NC) and inorganic nanoparticle (e.g., ZrO2, SiO2, BaSO4, and hydroxyapatite). The robust cooler shows an interesting "brick-and-mortar" structure, where the NC constructs interwoven framework (as brick structure) and the inorganic nanoparticle uniformly locates in the skeleton (as mortar structure), collectively contributing to high mechanical strength (>80 MPa) and flexibility. In addition, the structural and chemical distinctions enable our cooler to show a high solar reflectance (>96 %) and mid-infrared emissivity (>0.9), demonstrating a sub-ambient average temperature drop of 8.8 °C in long-term outdoor environments. The high-performance cooler with robustness, scalability and environmental friendliness, serves as a competitive participant toward the advanced PDRC materials in our low-carbon society.

5.
Front Chem ; 11: 1150635, 2023.
Article in English | MEDLINE | ID: mdl-37025549

ABSTRACT

Bamboo fiber/polypropylene composites (BPCs) have been widely used in buildings, interior decoration, and automobile components. However, pollutants and fungi can interact with the hydrophilic bamboo fibers on the surface of Bamboo fiber/polypropylene composites, degrading their appearance and mechanical properties. To improve their anti-fouling and anti-mildew properties, a superhydrophobic modified Bamboo fiber/polypropylene composite (BPC-TiO2-F) was fabricated by introducing titanium dioxide (TiO2) and poly(DOPAm-co-PFOEA) onto the surface of a Bamboo fiber/polypropylene composite. The morphology of BPC-TiO2-F was analyzed by XPS, FTIR, and SEM. The results showed that TiO2 particles covered on Bamboo fiber/polypropylene composite surface via complexation between phenolic hydroxyl groups and Ti atoms. Low-surface-energy fluorine-containing poly(DOPAm-co-PFOEA) was introduced onto the Bamboo fiber/polypropylene composite surface, forming a rough micro/nanostructure that endowed BPC-TiO2-F with superhydrophobicity (water contact angle = 151.0° ± 0.5°). The modified Bamboo fiber/polypropylene composite exhibited excellent self-cleaning properties, and a model contaminant, Fe3O4 powder, was rapidly removed from the surface by water drops. BPC-TiO2-F showed excellent anti-mold performance, and no mold was on its surface after 28 days. The superhydrophobic BPC-TiO2-F had good mechanical durability and could withstand sandpaper abrasion with a weight load of 50 g, finger wiping for 20 cycles, and tape adhesion abrasion for 40 cycles. BPC-TiO2-F showed good self-cleaning properties, mildew resistance, and mechanical resistance, giving it promising applications for automotive upholstery and building decoration.

6.
Int J Biol Macromol ; 238: 124031, 2023 May 31.
Article in English | MEDLINE | ID: mdl-36933599

ABSTRACT

Actuators are widely used in bionic devices and soft robots, among which invisible actuators have some unique applications, including performing secret missions. In this paper, highly visible transparent cellulose-based UV-absorbing films were prepared by dissolving cellulose raw materials using N-methylmorpholine-N-oxide (NMMO) and using ZnO nanoparticles as UV absorbers. Furthermore, transparent actuator was fabricated by growing highly transparent and hydrophobic polytetrafluoroethylene (PTFE) film on regenerated cellulose (RC)-ZnO composite film. In addition to its sensitive response to Infrared (IR) light, the as-prepared actuator also shows a highly sensitive response to UV light, which is attributed to the strong absorption of UV light by ZnO NPs. Thanks to the drastic differences in adsorption capacity between the RC-ZnO and PTFE materials for water molecules, the asymmetrically- assembled actuator demonstrates extremely high sensitivity and excellent actuation performance, with a force density of 60.5, a maximum bending curvature of 3.0 cm-1, and a response time of below 8 s. Bionic bug, smart door and the arm of excavator made from the actuator all exhibit sensitive responses to UV and IR lights.


Subject(s)
Nanoparticles , Zinc Oxide , Ultraviolet Rays , Cellulose/chemistry , Water/chemistry , Nanoparticles/chemistry
7.
Adv Sci (Weinh) ; 10(8): e2207202, 2023 Mar.
Article in English | MEDLINE | ID: mdl-36748279

ABSTRACT

Interfacial engineering is a vital strategy to enable high-performance perovskite solar cells (PSCs). To develop efficient, low-cost, and green biomass interfacial materials, here, a bifunctional cellulose derivative is presented, 6-O-[4-(9H-carbazol-9-yl)butyl]-2,3-di-O-methyl cellulose (C-Cz), with numerous methoxy groups on the backbone and redox-active carbazole units as side chains. The bifunctional C-Cz shows excellent energy level alignment, good thermal stability and strong interactions with the perovskite surface, all of which are critical for not only carrier transportation but also potential defects passivation. Consequently, with C-Cz as the interfacial modifier, the PSCs achieve a remarkably enhanced power conversion efficiency (PCE) of 23.02%, along with significantly enhanced long-term stability. These results underscore the advantages of bifunctional cellulose materials as interfacial layers with effective charge transport properties and strong passivation capability for efficient and stable PSCs.

8.
Carbohydr Polym ; 306: 120617, 2023 Apr 15.
Article in English | MEDLINE | ID: mdl-36746574

ABSTRACT

Liquid marbles, as particle-armored droplets, have potential applications in microreactors, biomedicine, controlled release and gas detection. To improve the stability and biocompatibility of marble, biocompatible cellulose acetate particles and 3-allyloxy-2-hydroxy-propyl-cellulose (AHP-cellulose) were used to fabricate robust cellulose-based liquid marbles with excellent stability. Liquid marble was gelled into hydrogel marble via blue-light-irradiated polymerization of AHP-cellulose. The mechanical properties of cellulose-based hydrogel marble are superior to those of liquid marble. The rupture height of liquid marble is 10.5 m, which is 420 times greater than that of water marble (0.025 m). Surprisingly, the hydrogel marble with a 3 % AHP-cellulose concentration remained intact even after being dropped from a height of 50 m, which is comparable with the ability of a leather ball to withstand larger impact. When released from a height of 60 mm, hydrogel marble bounced to approximately 25.5 mm, 881 % higher than liquid marble (2.6 mm). Hydrogel marble exhibited long-lasting stability and was capable of monitoring ammonia with a detection limit of 365.2 mg/m3. The biocompatible cellulose-based hydrogel marble with excellent mechanical stability and reusability detection has great potential in chemical and environmental engineering as gas sensors.

9.
Int J Biol Macromol ; 226: 833-839, 2023 Jan 31.
Article in English | MEDLINE | ID: mdl-36521706

ABSTRACT

Forward osmosis (FO) technology exhibits great potential in seawater desalination and wastewater treatment due to its negligible energy consumption and high antifouling, however, the weak desalination capability, especially low water flux, remains challenging. Herein, a cost-effective and high-desalination-performance chitosan (CS)-based FO membrane is developed via coupling the electrospinning CS nanofibers and interfacial-polymerized polyamide (PA). The electrospun nanofibers construct the porous and hydrophilic CS layer with the large pore-diameter of ~274 nm and low thickness of ~10 µm, enabling the effective transport of water molecules, specifically, a superhigh water flux of 107.53 LMH at a low salt-water ratio of 0.24 g·L-1. In addition, such superior desalination performance of the as-prepared FO membrane is universal for the various salt species and concentrations. Our CS nanofiber-based membrane with the high separation capability of water-salt, desirable antibacterial activity, as well as the low cost, offers a roadmap toward the sustainable membrane materials.


Subject(s)
Chitosan , Nanofibers , Water Purification , Water , Membranes, Artificial , Osmosis
10.
Biomater Adv ; 136: 212765, 2022 May.
Article in English | MEDLINE | ID: mdl-35929329

ABSTRACT

Hydrogels are functional materials that are similar to human skin and have received much attention in recent years for biomedical applications. However, the preparation of nontoxic, highly adhesive, and antimicrobial hydrogels in an efficient way remains a great challenge. Inspired by adhesive mussel foot proteins (mfps) which consist of abundant catecholic amino acids and lysine (Lys) residues, gallic acid-modified ε-poly-L-lysine (EPL/GA) was synthesized, and an active functional monomer (AA-EPL/GA) was then created through a reaction with acrylic acid (AA). The polymerization of AA-EPL/GA occurred rapidly (30-160 s) under blue light (λ = 405 nm) irradiation to produce a biomimetic PAA-EPL/GA hydrogel under mild conditions. The biomimetic pyrogallol-Lys distribution endowed the PAA-EPL/GA hydrogels with superior adhesion in humid environments (with an adhesive strength of 50.02 kPa toward wet porcine skin) and tunable mechanical and self-healing properties. Additionally, the PAA-EPL/GA hydrogels exhibited outstanding antibacterial ability due to the inherent characteristics of GA and EPL. In a mouse model, PAA-EPL/GA adhered firmly around the wound tissues. Photographs of the wound and the histological results demonstrated the ability of the hydrogel to promote wound healing, control wound infection, and suppress scar formation. Moreover, the hydrogel had a good hemostatic effect on liver bleeding. Our results highlighted the promising application potential of GA-based hydrogels, which were easily, harmlessly, and efficiently fabricated by blue light irradiation.


Subject(s)
Hemostatics , Hydrogels , Adhesives/pharmacology , Animals , Anti-Bacterial Agents/pharmacology , Bionics , Hemostatics/pharmacology , Humans , Hydrogels/pharmacology , Mice , Pyrogallol/chemistry , Resin Cements , Swine , Wound Healing
11.
Int J Biol Macromol ; 212: 275-282, 2022 Jul 01.
Article in English | MEDLINE | ID: mdl-35594941

ABSTRACT

Soft and elastic polymer hydrogel materials are booming in the fields of wearable biomimetic skin, sensors, robotics, and bioelectrodes. Currently, many researchers are exploring new chemistries for the preparation of hydrogels to improve their performance. In the present study, we design and develop a strategy to prepare lignin reinforced hydrogels based on disulfide bond crosslinking mechanisms, and resultant hydrogels exhibit excellent stretchability, with tensile strain of up to 1085.4%, and high adhesion (with the highest T-peel strength of up to 432.2 N/m to pigskin). The underlying mechanism is based on the disulfide bonds that act as crosslinkers in the as-prepared hydrogel, and they can be easily cleaved and re-formed under mild conditions. Thanks to the presence of lignin, the as-obtained hydrogels also have excellent UV shielding effect. When assembled into a strain sensor, they can output stable and sensitive sensing signals, with gauge factor (GF) of 2.72 (strain: 0-72.8%). Furthermore, a simple and effective strategy to construct asymmetric adhesive hydrogels was adopted, which is based on directional soaking of the top portion of the hydrogel in a high-concentrated calcium chloride solution. The asymmetric hydrogel strain sensor transmits accurate and stable signals without the interference of various contaminants.


Subject(s)
Hydrogels , Lignin , Adhesives/chemistry , Disulfides , Electric Conductivity , Hydrogels/chemistry
12.
Front Chem ; 10: 840133, 2022.
Article in English | MEDLINE | ID: mdl-35372284

ABSTRACT

In this work, a simple synthetic method was used to prepare a new type of magnetic dissolving pulp (MDP) @polydopamine (PDA) fibers. The hydroxyl groups of the fibers were converted into carboxyl groups after succinylation. Fe3O4 nanoparticles were grown in situ on the fibers. The prepared MDP@PDA fibers have catalytic reduction efficiency and adsorption performance for methylene blue organic dyes, and it has been thoroughly tested under various pH conditions. Fe3O4@PDA fibers have high reusability, are easy to separate, and regenerate quickly. The catalytic and adsorption efficiency barely decreases after repeated use. The surface of dissolving pulp fibers with a functionalized multifunctional PDA coating is used to create multifunctional catalysts and adsorbent materials. This study presents a very useful and convenient method for the synthesis and adjustment of MDP@PDA fibers, which have a wide range of potential applications in catalysis and wastewater treatment.

13.
Colloids Surf B Biointerfaces ; 215: 112509, 2022 Jul.
Article in English | MEDLINE | ID: mdl-35472651

ABSTRACT

Conductive hydrogels have attracted significant attention as a promising material in electrical and biomedical fields. However, the simultaneous realization of good conductivity, toughness, high tissue adhesiveness, excellent biocompatibility, and extreme environmental tolerance remains a challenge. Inspired by the antifreezing/antiheating behavior of natural plants, a calcium chloride/TEMPO-oxidized cellulose nanofiber-dopamine/ polyacrylamide (CaCl2/TOCNF-DOPA/PAM) glycerol/water organohydrogel with antifreezing and antiheating properties, good transparency, conductivity, stability, excellent biocompatibility, mechanical properties, and tissue adhesiveness was fabricated. The organohydrogel has about 700% stretchability, with about 90% transparency. The organohydrogel exhibits good conductivity of 4.9 × 10-4 S/cm and high tissue adhesiveness of 50 kPa, which can monitor various human activities. The organohydrogel displays excellent extreme environmental tolerance to maintain the conductivity and mechanical properties under an extremely wide temperature range (-24 to 50 °C) for a long period due to its water-locking effect between glycerol and water molecules. The biocompatible organohydrogel is able to protect the skin from frostbite or burns in harsh environments. The plant-inspired stable and durable organohydrogel is used as a wearable dressing for multifunctional sensors.


Subject(s)
Adhesives , Wearable Electronic Devices , Bandages , Electric Conductivity , Glycerol , Humans , Hydrogels , Water
14.
Biomacromolecules ; 23(6): 2272-2279, 2022 06 13.
Article in English | MEDLINE | ID: mdl-35486379

ABSTRACT

Smart functional fillers can significantly enhance the comprehensive properties of ionic hydrogels, such as their mechanical properties, which are key features of hydrogels in wearable sensor applications. As a plant-derived natural polymer, hemicellulose can serve as smart functional fillers. In this study, tannic acid-modified hemicellulose nanoparticles (TA@HC) and Fe3+ were used in the preparation of PAA/TA@HC/Fe3+ hydrogels. The addition of TA@HC and Fe3+ in the sodium persulfate (SPS) and acrylic acid (AA) polymerization system resulted in a fast gelation process that was completed within a short time (as short as 30 s) at room temperature. The catechol-rich TA and Fe3+ system allows for quick activation of SPS to produce free radicals, generating abundant hydroxyl groups in a short period of time, which was responsible for the fast gelation. Furthermore, due to the TA@HC effect and the dynamic catechol (TA)-Fe3+ redox system, the PAA/TA@HC/Fe3+ hydrogel exhibited excellent mechanical properties with an exceptionally high strain (as high as 5600%), adhesiveness, rapid and efficient self-healing ability, and reproducible self-adhesion onto various substrates. More importantly, asymmetric adhesive PAA/TA@HC/Fe3+ hydrogels were prepared by selective Fe3+ coating of the upper hydrogel surface to render the top surface nonadhesive so that the same hydrogel with different adhesiveness between the upper and bottom surfaces was obtained. The asymmetric adhesive hydrogel design permits the adhesive side to fit comfortably to the skin and the nonadhesive side showing anti-interference against various different pollutant materials, accurately serving as a pressure sensor.


Subject(s)
Hydrogels , Nanoparticles , Adhesives/chemistry , Catechols , Hydrogels/chemistry , Ions/chemistry , Polysaccharides
15.
ACS Biomater Sci Eng ; 8(3): 1096-1102, 2022 03 14.
Article in English | MEDLINE | ID: mdl-35213139

ABSTRACT

Traditional adhesives with strong adhesion are widely applied in the fields of wood, building, and electronics. However, the synthesis and usage of commercial adhesives are not eco-friendly, which are harmful to human health and to the environment. In this study, a green cellulose nanofibrils/poly(hydroxyethyl methacrylate-co-dopamine methacrylamide) (CNFs/P(HEMA-co-DMA)) adhesive with excellent biocompatibility and strong bonding strength has been fabricated. P(HEMA-co-DMA) with a catechol content of 7.1 mol % was synthesized using dopamine methacrylamide and hydroxyethyl methacrylate. The CNFs/P(HEMA-co-DMA) adhesive was generated by cross-linking P(HEMA-co-DMA) solution using cellulose nanofibrils (CNFs). Strong adhesion was realized on various substrates, with a maximum lap shear strength of 5.50 MPa on steel. The NIH 3T3 cells test demonstrated that the adhesive possessed excellent biocompatibility. The green catechol-containing CNFs-cross-linked adhesive has promising potential for applications in medicine, electronic, food packaging, and engineering.


Subject(s)
Adhesives , Cellulose , Animals , Catechols , Dopamine , Engineering , Humans , Mice
16.
ACS Appl Mater Interfaces ; 14(7): 8728-8742, 2022 Feb 23.
Article in English | MEDLINE | ID: mdl-35143167

ABSTRACT

Recently, versatile hydrogels with multifunctionality have been widely developed with emerging applications as wearable and implantable devices. In this work, we reported novel versatile hydrogels by self-catalyzing the gelation of an interpenetrating polymer network consisting of acrylic acid (AA) monomers and GA-modified collagen (GCOL) in situ decorated silver nanoparticles (AgNPs). The resultant hydrogel, namely AgNP@GCOL/PAA, has many desirable features, including good mechanical properties (such as 123 kPa, 916%, and 1961 J m-2 for the fracture stress, strain and tearing energy) that match with those of animal skin, excellent self-healing performance, favorable conductivity and strain sensitivity as a flexible biosensor, and excellent antibacterial and anti-UV properties, as well as the strong adhesiveness on skin. Moreover, AgNP@GCOL/PAA showed excellent biocompatibility via in vitro cell culture. Remarkably, AgNP@GCOL/PAA displayed superior hemostatic properties with sharply decreasing blood loss for a mouse liver incision, closely related to its strong self-adhesion which produced anchoring strength to the bleeding site and thus formed a network barrier with liver tissue. This study provides new opportunities for the facile preparation of widely used multifunctional collagen-based hydrogels based on a simple pyrogallol-Ag system.


Subject(s)
Hydrogels , Metal Nanoparticles , Adhesives , Animals , Anti-Bacterial Agents/pharmacology , Catalysis , Collagen , Hydrogels/pharmacology , Mice , Pyrogallol , Silver/pharmacology
17.
Int J Biol Macromol ; 200: 226-233, 2022 Mar 01.
Article in English | MEDLINE | ID: mdl-34999036

ABSTRACT

Hydrogels have found applications in many different fields. However, poor mechanical properties, such as low elasticity and lack of rapid recovery under large deformation, can severely limit their applications. In this study, we developed lignin reinforced hydrogels made of calcium ion containing ternary polymers (lignosulfonate (LS), alginate (Alg), and polyacrylic acid (PAA)). The resultant hydrogel has excellent elasticity, rapid self-recovery, and multi-functionalities. The covalent PAA network acts as the elastic scaffold of hydrogel, while calcium bridging networks of LS, Alg, and PAA, as well as the strong hydrogen bonding network in the system, function as sacrifice bonds to dissipate energy and transfer stress. The PAA/LS/Alg/Ca hydrogels exhibit rapid and durable elastic recovery ability under large deformation with the highest compressive stress of 835 kPa (95% strain), highest tensile fracture stress of 357 kPa, and highest tensile strain of 1144%. In addition, these tough hydrogels show UV resistance, self-healing, antifreeze, and excellent electro-conductivity. When assembled into a strain sensor, stable and reliable electrical responses with 375 ms response time are demonstrated. The PAA/LS/Alg/Ca hydrogel strain sensors can monitor human movements with responsive and accurate physiological signals. These results support the conclusion that the PAA/LS/Alg/Ca hydrogel strain sensors have great application potential in flexible wearable electronics and smart devices.


Subject(s)
Hydrogels
18.
Int J Biol Macromol ; 201: 104-110, 2022 Mar 15.
Article in English | MEDLINE | ID: mdl-34998868

ABSTRACT

Flexible hydrogels with integration of excellent mechanical and electrical properties are well suited for applications as wearable electronic sensors, and others. Self-adhesion is an important feature of wearable sensors. However, the usual isotropic- adhesion hydrogels have the drawback of poor anti-interference, which negatively affects their applications. In this study, we developed asymmetric-adhesion and tough lignin reinforced hydrogels in a facile two-step process: 1) PAA hydrogels, with lignin as the binder and conductive filler, were first prepared; 2) the asymmetric-adhesion property was imparted to lignin reinforced hydrogel by simple soaking of the top portion of the hydrogel in CaCl2 solution. The as-obtained asymmetric-adhesion lignin reinforced hydrogel was assembled into a wearable sensor, which shows excellent anti-interference and accurate and stable collections of sensing signals, with its gauge factor (GF) of 2.51 (in the strain range of 0-51.5%). In addition, the tough hydrogel is capable of generating electricity upon moist air sweeping through it, showing excellent energy conversion capabilities, with open-circuit voltage of as high as 306.6 mV. These results provided new prospects for the application of polyelectrolyte hydrogel materials in the fields of wet-to-electric conversion and wearable electronic sensors.


Subject(s)
Hydrogels , Wearable Electronic Devices , Electric Conductivity , Electricity , Lignin
19.
Front Bioeng Biotechnol ; 9: 804456, 2021.
Article in English | MEDLINE | ID: mdl-34917604

ABSTRACT

Chemical pretreatment followed by enzymatic hydrolysis has been regarded as a viable way to produce fermentable sugars. Phenylsulfonic acid (PSA) pretreatment could efficiently fractionate the non-cellulosic components (hemicelluloses and lignin) from bamboo and result in increased cellulose accessibility that was 10 times that of untreated bamboo. However, deposited lignin could trigger non-productive adsorption to enzymes, which therefore significantly decreased the enzymatic hydrolysis efficiency of PSA-pretreated bamboo substrates. Herein, poly(N-vinylcaprolactam) (PNVCL), a non-ionic surfactant, was developed as a novel additive for overcoming the non-productive adsorption of lignin during enzymatic hydrolysis. PNVCL was found to be not only more effective than those of commonly used lignosulfonate and polyvinyl alcohol for overcoming the negative effect of lignin, but also comparable to the robust Tween 20 and bovine serum albumin additives. A PNVCL loading at 1.2 g/L during enzymatic hydrolysis of PSA pretreated bamboo substrate could achieve an 80% cellulosic enzymatic conversion and meanwhile reduce the cellulase loading by three times as compared to that without additive. Mechanistic investigations indicated that PNVCL could block lignin residues through hydrophobic interactions and the resultant PNVCL coating resisted the adsorption of cellulase via electrostatic repulsion and/or hydration. This practical method can improve the lignocellulosic enzymatic hydrolysis efficiency and thereby increase the productivity and profitability of biorefinery.

20.
ACS Omega ; 6(47): 31683-31688, 2021 Nov 30.
Article in English | MEDLINE | ID: mdl-34869992

ABSTRACT

In the present study, the immobilization of free pectinase onto polystyrene resin beads via crosslinking with glutaraldehyde was investigated. The immobilized pectinase was characterized by Fourier transform infrared spectroscopy and confocal laser scanning microscopy. After optimizing the immobilization conditions, the optimum pH of immobilized pectinase shifted from 8.0 to 8.5 and the optimum temperature shifted from 45 to 60 °C, showing its improved stability to temperature and pH compared with the free pectinase. The Michaelis-Menten constant K m value of free and immobilized pectinase was determined to be 1.95 and 5.36 mM, respectively. The storage stability of immobilized pectinase was demonstrated with 36.8% of the initial activity preserved after 30 days at 25 °C. The reusability of the immobilized pectinase activity was 54.6% of its initial activity after being recycled six times. Therefore, based on the findings mentioned above, it can be inferred that this simple immobilization technique for pectinase appears to be promising for industrial applications.

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