GIANT最新文献

Biomaterials that can be reversibly stiffened and shaped could be useful in broad biomedical applications where form-fitting scaffolds are needed. Here we investigate the combination of strong non-linear elasticity in biopolymer networks with the reconfigurability of packed hydrogel particles within a composite biomaterial. By packing microgels into collagen-1 networks and characterizing their linear and non-linear material properties, we empirically determine a scaling relationship that describes the synergistic dependence of the material's linear elastic shear modulus on the concentration of both components. We perform high-strain rheological tests and find that the materials strain stiffen and also exhibit a form of programmability, where no applied stress is required to maintain stiffened states of deformation after large strains are applied. We demonstrate that this non-linear rheological behavior can be used to shape samples that do not spontaneously relax large-scale bends, holding their deformed shapes for days. Detailed analysis of the frequency-dependent rheology reveals an unexpected connection to the rheology of living cells, where models of soft glasses capture their low-frequency behaviors and polymer elasticity models capture their high-frequency behaviors.

Wound healing requires a contamination-free, sterile, and breathable environment. However, to develop an ideal wound dressing with all these functionalities simultaneously poses significant challenges. In this study, we designed a wound dressing that mimics the structure of skin with good breathability and protective functions. The wound dressing consists of a hydrophilic Poly(3-hydroxybutyrate-co-4-hydroxybutyrate) (P34HB) membrane coated with zinc oxide nanoparticles and a hydrophobic polyvinylidene fluoride (PVDF) membrane. Meanwhile, plasma treatment was also utilized to bond the two layers, resulting in an enhancement of 60 % in mechanical properties. The crosslinked fibrous membranes exhibited uniform stress distribution when stretching. Due to the unique structures of the wound dressing, it demonstrates wound exudate management, antibacterial functions, and hemostatic properties. The hydrophobic layer guided wound exudate towards the hydrophilic layer and the zinc oxide nanoparticles acted as a barrier against external bacteria and released zinc ions to inhibit bacterial growth in the exudate. Moreover, the water vapor transmission rate (WVTR) was measured to be over 86.55 kg/m²/day, the hemolysis rate was 2.38 %, and an impressive 81.98 % healing rate was recorded during in vitro wound healing. This skin-mimicking wound dressing shows great potential as a promising solution for the therapy of chronic wounds and infections.

The field of bone regeneration has witnessed significant advancements with the exploration and incorporation of marine biomaterials, offering promising avenues for orthopaedic and dental applications. Marine environments are a rich source of biological materials with unique properties conducive to bone healing and regeneration. Repurposing and reusing some waste by-products of marine products for bone regeneration not only contribute to environmental protection but also drives the development of the marine economy, thereby achieving sustainable development. Moreover, the lower production costs associated with the abundant availability and easy processing of marine biomaterials make bone regeneration therapies more accessible to a broader population, enhancing global health equity. By exploring the current research progressions on marine biomaterials and recounting their sources, properties, mechanisms of action, and applications in bone regeneration research, this review provides a comprehensive overview of the potential and challenges of marine biomaterials for future bone healing and regeneration applications.

This study investigates the development of sustainable multifunctional foams utilizing hemp stalk waste, lignin, xylan, pectin, glycerol, and citric acid. Using the freeze-drying method for foam formation in combination with industrial waste products and renewable resources, we emphasize a green, scalable material development approach. In total, 25 distinct formulations were prepared and methodically examined, mainly focusing on the roles of citric acid, pectin, and glycerol. Thermal crosslinking, conducted at 140°C, was analyzed using FTIR, confirming the formation of ester bonds. The microstructural characterization of the foams revealed distinct variations from nanofibrillar to microfibrillar structures based on composition. The bulk density of the foams ranged from 13 to 152 mg/cm³, and porosity values varied from 97 % to 99 % for most of the compositions. Foams showed up to 50 g/g water, 51 g/g rapeseed oil, and 46 g/g kerosine absorption. Foam absorption capacity changes were examined through 10 iterative cycles in water, demonstrating that most compositions retained near-original absorption capacities. Adding glycerol conferred exceptional hydrophobic properties to the foam surfaces, as evidenced by water contact angles ranging between 140° and 150°. The thermal conductivity of foams ranged from 0.040 to 0.046 W/mK. The mechanical properties of foams were assessed using compression testing, which showed highly tunable structures ranging from soft to rigid. This study illustrates the broad applicability of these foams, emphasizing their utility in thermal insulation, filtration systems, and environmental cleanup, among other potential uses.

Despite the excellent lubricity of conventional hydrogel materials due to their wet-soft properties, they produce severe mechanical elastic deformation at higher interfacial contact stresses. Balancing the load-bearing capacity and lubricating properties of hydrogel material is the difficulty of the current research work for articular cartilage substitutes. Great progress has been made in developing bionic joint materials with high load-bearing and low-friction hydrogels based on gradient designs. However, most bionic materials are based on sliding friction greatly limiting the improvement of lubrication performance. Herein, we designed and prepared a new hydrogel material with high load-bearing capacity and stable lubrication performance, breaking through the traditional friction method and turning to “sliding” for “rolling”. The network on the hydrogel surface was dissociated by UV irradiation and the pores on the surface were filled with SiO₂ nanoparticles. The dense network structure of the underlying layer endows the hydrogel material with good load-bearing properties, while the high degree of hydration of the surface layer and the rolling friction effect of SiO₂ nanoparticles greatly enhance the lubrication property. With the synergistic effect of these designs, the multi-layered hydrogel with nanoparticles on the surface achieved an ultra-low average coefficient of friction (COF) of ∼0.00809 at a high load of 50 N during 30,000 cycles. This idea of hydrogel material design provides a new strategy for the replacement of biomimetic articular cartilage materials.

Organic photodetectors (OPDs) own unique advantages such as light weight, flexibility, low production cost, tunable detection wavelength, and thus are promising for a variety of applications. The lack of hole-blocking layer (HBL) materials impedes the reduction of dark current density and the enhancement of the performance of OPDs. Herein, we employed an n-type polythiophene n-PT1 as a HBL material for inverted OPDs. The specific solubility of n-PT1 in o-dichlorobenzene facilitates solution processing and enables multilayer device fabrication. The ultradeep-lying highest occupied molecular orbital energy level ensures a large hole injection barrier between cathode and active layer that suppresses dark current. As a result, compared to the control devices without n-PT1, the inverted OPD devices with n-PT1 as HBL demonstrate a two-order-of-magnitude reduction in dark current density and a one-order-of-magnitude increase in specific detectivity. To the best of our knowledge, this is the first solution processable HBL material for inverted OPDs.

Side-chain modification and asymmetric design for non-fullerene acceptors (NFAs) have been proven to be effective methods for harvesting high-performance organic solar cells (OSCs). Combining the two molecular design strategies, we adopted phenyl chain and alkyl chains with different shapes to develop two novel asymmetric NFAs, named BTP-P2EHC11 and BTP-P2EHC2C4. Compared with BTP-P2EHC2C4 attached 2-ethylhexyl side chain, BTP-P2EHC11 with linear alkyl side chain have slightly red-shifted absorption and intensive absorption strength. Moreover, the PM6:BTP-P2EHC11 blend film presents higher and more balanced charge mobilities, reducing charge recombination, tighter intermolecular packing and more favorable fibrous network morphology with appropriate phase separation than PM6:BTP-P2EHC2C4, which lead to significantly enhanced short-circuit current density (J_SC) of PM6:BTP-P2EHC11-based devices. Thus, the OSCs based on PM6:BTP-P2EHC11 achieve a superior power conversion efficiency (PCE) of 18.50% with a good trade-off among open-circuit voltage (V_OC) of 0.876 V, J_SC of 26.85 mA cm⁻² and fill factor (FF) of 78.65%, while PM6:BTP-P2EHC2C4-based device exhibits a lower PCE of 17.49%. Our investigation elucidates that the combination of finely optimizing the shape of alkyl-chain and asymmetric side groups of NFAs could pave a promising avenue toward morphology optimization and performance promotion of OSCs.

The low-temperature environment caused by solvent evaporation leads to the condensation of water vapor into water droplets that remain on the surface of the film to form breath figure patterns. The conventional approach to regulate the pore morphology in the breath figure process is to optimize the ambient temperature, humidity, and solution concentration. However, realizing a wide adjustable window of pore size and uniform distribution of the pore are still challenges. Here, inspired by the rainfall phenomenon, we proposed a simple and efficient method called the “raining boxing method” (RBM) for preparing porous films based on exogenously given water droplets as templates. The RBM broadened the adjustable window of pore size (0.6–225 µm in this work) and solved the inherent problem of radial reduction of pore size from the film center to the edge caused by the significant difference in low-temperature duration at different locations accompanying the solvent evaporation process. Furthermore, this method could realize multi-types porous films, including surface porous films, spongy porous films, and honeycomb porous films, and could be universally applied in the casting process of various polymer solutions.

Soft adhesive systems (SASs), which consist of a soft adhesive layer and/or soft adherends, have been extensively applied in advanced fields such as biomedicine, flexible electronics, and soft robotics. Understanding the fatigue failure of SASs is crucial for ensuring their structural safety and functional stability, as they are often subjected to fatigue loading. This paper systematically reviews the fatigue failure of SASs, aiming to provide a comprehensive understanding and contribute to the study of fatigue failure mechanisms and lifetime prediction of SASs. The review starts by introducing classical research methods for fatigue failure of adhesive systems, with a focus on total fatigue lifetime and fatigue crack growth (FCG). After summarizing the complexity of fatigue failure in SASs, it provides an overview of fatigue research for the three types of SASs: “soft interface”, “soft adherend”, and “soft-soft” adhesive systems. Then, the relations between the fatigue failure and energy dissipation of various SASs are specifically discussed noting that significant energy dissipation accompanying the cyclic deformation of SASs during fatigue loading can substantially affect the final fatigue failure of SASs. Finally, the current unresolved issues and challenges in this field are presented.

The twist-bend nematic (N_TB) phase of achiral liquid crystals (LCs) manifests a unique self-assembled heliconical structure with nanometer-scale pitch length, mirroring the chiral symmetry-breaking phenomena in nature, thus sparking widespread research interest. However, the ingenious N_TB phase is only stable at high temperatures within a very limited temperature interval, often undergoing inevitable crystallization at low temperatures. Herein, room temperature supercooled N_TB material systems composed of meticulously designed LC dimer mixtures with varying molecular curvatures and central flexibility were developed, resulting in complete resistance to crystallization even after 1 year of storage. Furthermore, the proposed N_TB material systems demonstrated exceptional compatibility with common nematic LCs, facilitating the tailoring of overall physical parameters, particularly to achieve a sufficiently low bend elastic constant with excellent stability. This work represents a paradigmatic advancement forward in realizing stable N_TB phase materials with a broad temperature range and resistance to crystallization, thereby tackling the enduring and seemingly insurmountable challenge while providing impetus for further exploration of their applications in soft matter, crystallography, and advanced photonics.