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To achieve all-organic polymer with high dielectric performances, we have designed a novel side-chain liquid crystalline polymer (P7) with strong polar mesogen of (Z)-4-(2-cyano-2-phenylvinyl)benzonitrile (CSCN) attached to polycyclooctene backbone. The bis-cyano-substituted CSCN is board-shaped and exhibits a large dipole moment (8.54 D) which tilts ∼34.2° away from its molecular long axis. Consequently, CSCN shows unique dual molecular anisotropy: one from biaxial shape anisotropy and the other from polarization anisotropy. The complex phase behaviors of P7 were investigated employing mainly the techniques of differential scanning calorimetry and X-ray diffraction. Four liquid crystal (LC) phases are identified as K0, K1, K2 and K3, which are SmA, highly-ordered biaxial SmA, B5-like and B7-like, respectively, with the thermal stability increased in sequence. The experimental results indicate that the different LC phases are arisen from the competition and balance between π-π stacking and dipole-dipole interaction. While the face-to-face π-π stacking is dominant in K0 and K1, optimizing the dipole-dipole interaction causes the CSCN mesogens within the smectic layer to tilt and rotate, resulting in K2 and K3. We further investigated the dielectric properties of P7 films using polarization-electric field loops test. The dielectric constant (ε_r) of P7 is found to be LC structure dependent, which is increased when the LC phase is varied from K0 to K3. With an average ε_r of 9.7 achieved in K3 and the low dielectric loss (tan δ = 0.001), P7 film offers a promising material in advanced applications like energy storage and electronic devices.

Spiro-OMeTAD is a primary hole transport material (HTM) employed in most state-of-the-art regular perovskite solar cells (PSCs). The essential reliance on hygroscopic ionic dopants to enhance the conductivity and mobility of Spiro-OMeTAD has dramatically compromised the stability of PSCs. Here, we demonstrated excellent photovoltaic performance of PSCs by developing two dopant-free polymers, namely L1 and L2, using thieno[3,2-b]thiophene as a building block. It is found that the n-hexyl-modified thiophene side chains endow the polymer L2 with favorable crystallinity, unique self-assembly behavior, and a preferable face-on stacking orientation. After the addition of a small amount (10 %) of PM6 to create a polymer alloy named LPA, the above properties were further improved, and the resulting film exhibited a distinct fibrous morphology, resulting in increased hole mobility and effective defect passivation. Consequently, PSCs employing LPA as a dopant-free HTM afforded a high efficiency of 23.81 %. Importantly, LPA-based PSCs exhibit significantly enhanced operational stability with a T80 lifetime of 1572 h at 55 °C. This work provides a crucial guideline for the design of dopant-free polymers, thereby advancing the practical application of PSCs.

Herein, we demonstrate a simple approach to control the orientation of cylinder-forming nanostructures in polystyrene-block-poly(L-lactide) (PS-b-PLLA) BCP thin films through thermal annealing under a high-vacuum environment. Surface tension discrepancy between the constituent blocks is critical in controlling the aimed orientation of self-assembled nanostructures in block copolymer (BCP) thin films. For BCP self-assembly, temperature has been widely utilized as a thermodynamic state variable under ambient pressure conditions, whereas the use of high vacuum (low pressure) for thermal annealing is limited. It has been observed that temperature can alter the surface tension only marginally with increasing temperature for polymeric materials; as a result, the pressure dependence of surface tension for PS and PLLA was investigated. By increasing the vacuum degree during thermal annealing, the surface tension discrepancy between the PS and PLLA blocks can be reduced significantly. Accordingly, during thermal annealing under high vacuum degree, a neutral air polymer interface can be generated for the BCP thin films, resulting in the formation of perpendicular cylinders from the neutral surface of the thin film through BCP microphase separation.

The global community has encountered numerous challenges concerning environmental sustainability, encompassing issues like waste generation, depletion of natural resources, air pollution, and other threats to human well-being. Consequently, the pursuit of an eco-friendly environment has emerged as a critical concern in recent years. Polysaccharides, being natural biopolymers, have garnered significant attention owing to their distinctive properties that make them versatile for various applications. Numerous sustainable and environmentally friendly polysaccharides, such as chitosan, cellulose, starch, hyaluronic acid, alginate, and inulin, have been identified. This article highlights the characteristics of renewable polysaccharides, their categorization, and their potential to contribute to environmental sustainability. It introduces environmentally friendly extraction methods aimed at minimizing chemical pollution. Through the careful selection of diverse polysaccharides and the application of functionalization techniques, the article suggests the possibility of obtaining suitable superabsorbent hydrogels, appropriate nanocomposites, and effective scaffolds. The significance of utilizing polysaccharide-based materials is explored in detail, emphasizing their exceptional properties. Additionally, the article discusses the various applications of eco-friendly polysaccharides as sustainable polymers, including in agriculture, biomedicine, and food packaging.

In the era of smart and sustainable technology driven by naturally occurring materials, various nanocellulose-based materials play a crucial role. Shape memory behaviour and self-healing capabilities of nanocelluloses are emerging as focal points in numerous research domains. Nanocellulose and its derivatives such as cellulose nanocrystals (CNC) and cellulose nanofibers (CNF), are currently in the limelight due to their excellent shape-memory and self-healing properties, making them suitable for multifunctional devices. In this regard, CNF, as a cutting-edge material, has spurred researchers to explore its potential in developing contemporary multifunctional and personalized health devices. Therefore, a timely and comprehensive review is essential to gain deep insights into the effectiveness of shape-memory and self-healing capabilities of CNF for multifunctional devices. Herein, we first provide a brief introduction to all nanocellulose materials. This review also depicts recent advancements and breakthroughs in the large and effective synthesis of CNF-based hybrid materials. Next, focusing on their self-healing and shape-memory performance, this review sheds new light on the advanced applications of CNF materials. Finally, perspectives on the current challenges and opportunities in this field are summarized for future researchers to gain an in-depth understanding of CNF-based smart and sustainable materials.

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.

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.

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.

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.