Hierarchical Porous Reduced Graphene Oxide/Poly(l-lactic acid) Fiber Films: The Influence of Recrystallization on Strength
Ontology highlight
ABSTRACT:
SUBMITTER: Song J
PROVIDER: S-EPMC11209683 | biostudies-literature | 2024 Jun
REPOSITORIES: biostudies-literature
Similar Datasets
Project description:High torsional strength fibers are of practical interest for applications such as artificial muscles, electric generators, and actuators. Herein, we maximize torsional strength by understanding, measuring, and overcoming rheological thresholds of nanocarbon (nanotube/graphene oxide) dopes. The formed fibers show enhanced structure across multiple length scales, modified hierarchy, and improved mechanical properties. In particular, the torsional properties were examined, with high shear strength (914 MPa) attributed to nanotubes but magnified by their structure, intercalating graphene sheets. This design approach has the potential to realize the hierarchical dimensional hybrids, and may also be useful to build the effective network structure of heterogeneous materials.
| S-EPMC7810860 | biostudies-literature
Project description:The cost effective synthesis and patterning of carbon nanomaterials is a challenge in electronic and energy storage devices. Here we report a one-step, scalable approach for producing and patterning porous graphene films with three-dimensional networks from commercial polymer films using a CO2 infrared laser. The sp3-carbon atoms are photothermally converted to sp2-carbon atoms by pulsed laser irradiation. The resulting laser-induced graphene (LIG) exhibits high electrical conductivity. The LIG can be readily patterned to interdigitated electrodes for in-plane microsupercapacitors with specific capacitances of >4 mF cm-2 and power densities of ~9 mW cm-2. Theoretical calculations partially suggest that enhanced capacitance may result from LIG's unusual ultra-polycrystalline lattice of pentagon-heptagon structures. Combined with the advantage of one-step processing of LIG in air from commercial polymer sheets, which would allow the employment of a roll-to-roll manufacturing process, this technique provides a rapid route to polymer-written electronic and energy storage devices.
| S-EPMC4264682 | biostudies-literature
Project description:Graphene oxide (GO) sheets have been used as a model system to study how the mechanical properties of two-dimensional building blocks scale to their bulk form, such as paper-like, lamellar-structured thin films. Here, we report that the modulus of multilayer GO films can be significantly enhanced if some of the sheets are drastically weakened by introducing in-plane porosity. Nanometer-sized pores are introduced in GO sheets by chemical etching. Membrane-deflection measurements at the single-layer level show that the sheets are drastically weakened as the in-plane porosity increases. However, the mechanical properties of the corresponding multilayer films are much less sensitive to porosity. Surprisingly, the co-assembly of pristine and etched GO sheets yields even stiffer films than those made from pristine sheets alone. This is attributed to the more compliant nature of the soft porous sheets, which act as a binder to improve interlayer packing and load transfer in the multilayer films.
| S-EPMC6695419 | biostudies-literature
Project description:Herein, we report the incorporation of a 10 μm thick reduced graphene oxide (RGO) barrier layer in a plasticized poly(vinyl chloride) (PVC) film as the main constituent in ion-selective membranes used in potentiometric solid-contact ion-selective electrodes (SCISE). Fourier transform infrared attenuated total reflection (FTIR-ATR) and oxygen transmission rate (OTR) measurements showed that the embedded RGO barrier efficiently impedes the diffusion of liquid water, carbon dioxide and oxygen (O2) through the 400 μm thick PVC film, which causes potential instability and irreproducibility of the SCISEs. The measurements revealed that the RGO layer completely blocks the carbon dioxide diffusion, while it fully blocks the water diffusion for 16 h and reduced the OTR by 85% on average. The μm-thick RGO films used in this study were easier to handle and incorporate into host polymers, and form more efficient and robust barriers compared to the mono-, few- and multilayer graphene commonly applied as barrier layers for liquids and gases. We also demonstrated that the FTIR-ATR technique employed in the permeability measurements is a versatile and very sensitive technique for studying the diffusion of small amounts of water and carbon dioxide through graphene-based thin films.
| S-EPMC9080506 | biostudies-literature
Project description:A new self-assembly concept is introduced to form large and pristine films (15 cm in diameter) of reduced graphene oxide (RGO). The resulting film has different degrees of polarity on its two different sides due to the characteristic nature of the self-assembly process. The RGO film can be easily transferred from a glass substrate onto water and a polymer substrate after injection of water molecules between the RGO film and glass substrate using an electric steamer. The RGO film can also be easily patterned into various shapes with a resolution of around ± 10 μm by a simple taping method, which is suitable for mass production of printed electronics at low cost.
| S-EPMC4686933 | biostudies-literature
Project description:Poly(lactic acid) (PLA) represents one of the most widely used biodegradable polymers for food packaging applications. While this material provides many advantages, it is characterized by limited antioxidant and UV-barrier properties. Blending PLA with lignin is an attractive strategy to address these limitations. Lignin possesses antioxidant properties and absorbs UV-light and is a widely available low value byproduct of the paper and pulp industry. This study has explored the use of lignin nanoparticles to augment the properties of PLA-based films. A central challenge in the preparation of PLA-lignin nanoparticle blend films is to avoid nanoparticle aggregation, which could compromise optical properties as well as antioxidant activity, among others. To avoid nanoparticle aggregation in the PLA matrix, PLA-grafted lignin nanoparticles were prepared via organocatalyzed lactide ring-opening polymerization. In contrast to lignin and unmodified lignin nanoparticles, these PLA-grafted lignin nanoparticles could be uniformly dispersed in PLA for lignin contents up to 10 wt %. The addition of as little as the equivalent of 1 wt % of lignin of these nanoparticles effectively blocked transmission of 280 nm UV-light. At the same time, these blend films retained reasonable visible light transmittance. The optical properties of the PLA lignin blend films also benefited from the well-dispersed nature of the PLA-grafted nanoparticles, as evidenced by significantly higher visible light transmittance of blends of PLA and PLA-grafted nanoparticles, as compared to blends prepared from PLA with lignin or unmodified lignin nanoparticles. Finally, blending PLA with PLA-grafted lignin nanoparticles greatly augments the antioxidant activity of these films.
| S-EPMC9274615 | biostudies-literature
Project description:A versatile and convenient way to produce bioactive poly(lactic acid) (PLA) and poly(ε-caprolactone) (PCL) electrospun nanofibrous scaffolds is described. PLA and PCL are extensively used as biocompatible scaffold materials for tissue engineering. Here, biobased nano graphene oxide dots (nGO) are incorporated in PLA or PCL electrospun scaffolds during the electrospinning process aiming to enhance the mechanical properties and endorse osteo-bioactivity. nGO was found to tightly attach to the fibers through secondary interactions. It also improved the electrospinnability and fiber quality. The prepared nanofibrous scaffolds exhibited enhanced mechanical properties, increased hydrophilicity, good cytocompatibility and osteo-bioactivity. Therefore, immense potential for bone tissue engineering applications is anticipated.
| S-EPMC5951450 | biostudies-literature
Project description:Electrospinning offers a powerful route for building one-dimensional (1D) micro/nanostructures, but a common requirement for toxic or corrosive organic solvents during the preparation of precursor solution has limited their large scale synthesis and broad applications. Here we report a facile and low-cost way to prepare 1D porous carbon microfibers by using an electrospun fiber-like natural product, i.e., silk cocoon, as precursor. We surprisingly found that by utilizing a simple carbonization treatment, the cocoon microfiber can be directly transformed into 1D carbon microfiber of ca. 6 μm diameter with a unique three-dimensional porous network structure composed of interconnected carbon nanoparticles of 10~40 nm diameter. We further showed that the as-prepared carbon product presents superior electrochemical performance as binder-free electrodes of supercapacitors and good adsorption property toward organic vapor.
| S-EPMC3553486 | biostudies-literature
Project description:Poly-l-lactic acid (PLLA) is a synthetic, biocompatible, biodegradable polymer with good piezoelectric properties. The prepared PLLA films were annealed in the oven at 140 °C for 0 h, 3 h, 12 h, and 24 h, respectively. The influences of temperature treatment time on the optoelectronic properties of the PLLA films and piezoelectric sensors based on them were investigated. The morphology and crystal structure of the PLLA films obtained under various post-processing conditions were examined by scanning electron microscopy, X-ray diffraction, Raman spectroscopy, and ATR-FTIR spectroscopy. The micromechanical equipment for tension-compression measurements was built in the laboratory for the tested piezoelectric sensors. The analysis of the structure shows that the increase in the crystallite size of the PLLA film influences the growth of the piezoelectric signal of the sensors based on them. The vibrational analysis of the PLLA films confirmed their crystal structure. The improvement in the structure and the stretching of the dipole C[double bond, length as m-dash]O for the film obtained after 3 h treatment increased the piezoelectric properties of the PLLA films. The analysis of Raman mapping added information that the area of the ordered phase of the PLLA films depends on the time of temperature treatment. The maximum value of the piezoelectric signal was 0.98 mV for sensors prepared on films annealed for 3 h at a load of 20 N. For films without temperature annealing at the same load, the maximum value was 0.45 mV. Thus, efficient converters of mechanical energy into electrical energy were obtained, which opens new innovative perspectives for the creation of flexible pressure sensors based on PLLA.
| S-EPMC9516697 | biostudies-literature
Project description:Poly (lactic acid) (PLA) and poly (butylene succinate) (PBS) based films containing two different plasticizers [Acetyl Tributyl Citrate (ATBC) and isosorbide diester (ISE)] at three different contents (15 wt %, 20 wt % and 30 wt %) were produced by extrusion method. Thermal, morphological, mechanical and wettability behavior of produced materials was investigated as a function of plasticizer content. Filmature parameters were also adjusted and optimized for different formulations, in order to obtain similar thickness for different systems. Differential scanning calorimeter (DSC) results and evaluation of solubility parameter confirmed that similar miscibility was obtained for ATBC and ISE in PLA, while the two selected plasticizers resulted as not efficient for plasticization of PBS, to the limit that the PBS-30ATBC resulted as not processable. On the basis of these results, isosorbide-based plasticizer was considered a suitable agent for modification of a selected blend (PLA/PBS 80:20) and two mixing approaches were used to identify the role of ISE in the plasticization process: results from mechanical analysis confirmed that both produced PLA-PBS blends (PLA85-ISE15)-PBS20 and (PLA80-PBS20)-ISE15 could guarantee advantages in terms of deformability, with respect to the PLA80-PBS20 reference film, suggesting that the promising use of these stretchable PLA-PBS based films plasticized with isosorbide can provide novel solutions for food packaging applications.
| S-EPMC5551852 | biostudies-other