Improved Energy Harvesting Ability of Single-Layer Binary Fiber Nanocomposite Membrane for Multifunctional Wearable Hybrid Piezoelectric and Triboelectric Nanogenerator and Self-Powered Sensors.

While wearable self-powered electronic devices have shown promising improvements, substantial challenges persist in enhancing their electrical output and structural performance. In this work, a working mechanism involving simultaneous piezoelectric and triboelectric conversion within a monolayer-structured membrane is proposed. Single-layer binary fiber nanocomposite membranes (SBFNMs) (PVDF/CNTX@PAN/CNTX, DPCPCX) with two distinct interpenetrating nanocomposite fibers were created through co-electrospinning, incorporating multiwalled carbon nanotubes (CNTs) into polyvinylidene fluoride (PVDF) and polyacrylonitrile (PAN), respectively. The resulting membrane demonstrated an exceptional synergistic effect of piezoelectricity and triboelectricity along with a high machine-to-electric conversion capability. The addition of CNTs increased the PVDF ß-phase and the PAN planar zigzag conformation. As a result, the DPCPC0.5-SBFNMs-based piezoelectric nanogenerator exhibited excellent electrical output (187 V, 8.0 µA, and 1.52 W m-2), maintaining an exceptionally high level of output voltage compared with other piezoelectric nanogenerators. It successfully illuminated 50 commercial light-emitting diodes simultaneously. The output voltage of DPCPC0.5-SBFNMs was 5.1 and 4.6 times higher than that of PAN or PVDF single-fiber membranes, respectively. Furthermore, the peak voltage of DPCPC0.5-SBFNMs exceeded that of co-electrospinning PVDF/CNT1.0@PAN (DPCP1.0) and PVDF@PAN/CNT1.0 (DPPC1.0) by 20 and 10 V, respectively. The piezoelectric sensor made of DPCPC0.5-SBFNMs accurately sensed human movement, ranging from tiny to large, and demonstrated utility as an alarm in medical treatment, fire fighting, and monitoring. Endogenous triboelectricity is proposed in SBFNM piezoelectric materials, enhancing electromechanical conversion and electrical output capacity, thereby promising a wide application potential in self-powered wearable electronic devices.

Constructing triple-network cellulose nanofiber hydrogels with excellent strength, toughness and conductivity for real-time monitoring of human movements.

In recent years, there has been a lot of interest in developing composite hydrogels with superior mechanical and conductive properties. In this study, triple-network (TN) cellulose nanofiber hydrogels were prepared by using cellulose nanofiber as the first network, isotropic poly(acrylamide-co-acrylic acid) as the second network, and polyvinyl alcohol as the third network via a cyclic freezing-thawing process. The strong (9.43 ± 0.14 MPa tensile strength, (445.5 ± 7.0)% elongation-at-break), tough (15.12 ± 0.14 MJ/m3 toughness), and conductive (0.0297 ± 0.00021 S/cm ionic conductivity) TN cellulose nanofiber hydrogels were effectively created after being pre-stretched in an external force field, cross-linked by Fe3+ and added Li+. The produced composite TN cellulose nanofiber hydrogels were successfully used as a flexible sensor for real-time monitoring and detecting human movements, highlighting their potential for wearable electronics, medical technology, and human-machine interaction. CHEMICAL COMPOUNDS STUDIED IN THIS ARTICLE: Acrylamide (PubChem CID: 6579); Acrylic acid (PubChem CID: 6581); Ammonium persulfate (PubChem CID: 6579); N, N'-methylene bisacrylamide (PubChem CID: 17956053); Sodium bromide (PubChem CID: 253881); Sodium hydroxide (PubChem CID: 14798); Sodium hypochlorite (PubChem CID: 23665760); Sodium chlorite (PubChem CID: 23668197); 2,2,6,6-tetramethylpiperidinyl-1-oxide (PubChem CID: 2724126); Polyvinyl alcohol (PubChem CID: 11199); Lithium chloride (PubChem CID: 433294); Iron nitrate nonahydrate (PubChem CID: 129774236).

A Simple and Effective Physical Ball-Milling Strategy to Prepare Super-Tough and Stretchable PVA@MXene@PPy Hydrogel for Flexible Capacitive Electronics.

Biomimetic flexible electronics for E-skin have received increasing attention, due to their ability to sense various movements. However, the development of smart skin-mimic material remains a challenge. Here, a simple and effective approach is reported to fabricate super-tough, stretchable, and self-healing conductive hydrogel consisting of polyvinyl alcohol (PVA), Ti3 C2 Tx MXene nanosheets, and polypyrrole (PPy) (PMP hydrogel). The MXene nanosheets and Fe3+ serve as multifunctional cross-linkers and effective stress transfer centers, to facilitate a considerable high conductivity, super toughness, and ultra-high stretchability (elongation up to 4300%) for the PMP hydrogel with. The hydrogels also exhibit rapid self-healing and repeatable self-adhesive capacity because of the presence of dynamic borate ester bond. The flexible capacitive strain sensor made by PMP hydrogel shows a relatively broad range of strain sensing (up to 400%), with a self-healing feature. The sensor can precisely monitor various human physiological signals, including joint movements, facial expressions, and pulse waves. The PMP hydrogel-based supercapacitor is demonstrated with a high capacitance retention of ≈92.83% and a coulombic efficiency of ≈100%.

Piezoresistive Sensor Containing Lamellar MXene-Plant Fiber Sponge Obtained with Aqueous MXene Ink.

Sustainable biomass materials are promising for low-cost wearable piezoresistive pressure sensors, but these devices are still produced with time-consuming manufacturing processes and normally display low sensitivity and poor mechanical stability at low-pressure regimes. Here, an aqueous MXene ink obtained by simply ball-milling is developed as a conductive modifier to fabricate the multiresponsive bidirectional bending actuator and compressible MXene-plant fiber sponge (MX-PFS) for durable and wearable pressure sensors. The MX-PFS is fabricated by physically foaming MXene ink and plant fibers. It possesses a lamellar porous structure composed of one-dimensional (1D) MXene-coated plant fibers and two-dimensional (2D) MXene nanosheets, which significantly improves the compression capacity and elasticity. Consequently, the encapsulated piezoresistive sensor (PRS) exhibits large compressible strain (60%), excellent mechanical durability (10 000 cycles), low detection limit (20 Pa), high sensitivity (435.06 kPa-1), and rapid response time (40 ms) for practical wearable applications.

Solar-assisted high-efficient cleanup of viscous crude oil spill using an ink-modified plant fiber sponge.

Rapid and efficient clean-up of viscous crude oil spills is still a global challenge due to its high viscous and poor flowability at room temperature. The hydrophobic/oleophilic absorbents with three-dimensional porous structure have been considered as a promising candidate to handle oil spills. However, they still have limited application in recovering the high viscous oil. Inspired by the viscosity of crude oil depended on the temperature, a solar-heated ink modified plant fiber sponge (PFS@GC) is fabricated via a simple and environmentally friendly physical foaming strategy combined with in-situ ink coating treatment. After wrapping by the polydimethylsiloxane (PDMS), the modified PFS@GC (PFS@GC@PDMS) exhibits excellent compressibility, high hydrophobic (141° in water contact angle), solar absorption (> 96.0%), and oil absorptive capacity (12.0-27.8 g/g). Benefiting from the favorable mechanical property and photothermal conversion capacity, PFS@GC@PDMS is demonstrated as a high-performance absorbent for crude oil clean-up and recovery. In addition, PFS@GC@PDMS can also be applied in a continuous absorption system for uninterrupted recovering of oil spills on the water surface. The proposed solar-heated absorbent design provides a new opportunity for exploring biomass in addressing large-scale oil spill disasters.

Muscle-inspired double-network hydrogels with robust mechanical property, biocompatibility and ionic conductivity.

Inspired by muscle architectures, double network hydrogels with hierarchically aligned structures were fabricated, where cross-linked cellulose nanofiber (CNF)/chitosan hydrogel threads obtained by interfacial polyelectrolyte complexation spinning were collected in alignment as the first network, while isotropic poly(acrylamide-co-acrylic acid) (PAM-AA) served as the second network. After further cross-linking using Fe3+, the hydrogel showed an outstanding mechanical performance, owing to effective energy dissipation of the oriented asymmetric double networks. The average strength and elongation-at-break of PAM-AA/CNF/Fe3+ hydrogel were 11 MPa and 480 % respectively, which the strength was comparative to that of biological tissues. The aligned CNFs in the hydrogels provided probable ion transport channels, contributing to the high ionic conductivity, which was up to 0.022 S/cm when the content of LiCl was 1.5 %. Together with superior biocompatibility, the well-ordered hydrogel showed a promising potential in biological applications, such as artificial soft tissue materials and muscle-like sensors for human motion monitoring.

The effect of polytetrafluoroethylene particle size on the properties of biodegradable poly(butylene succinate)-based composites.

Poly(butylene succinate) (PBS)/polytetrafluoroethylene (PTFE) composites, including three types of PTFE powders, were prepared by melt blending using a HAAKE torque rheometer. Microcellular foams were successfully fabricated by batch foaming with supercritical fluids (scCO2). The effects of PTFE powder type on crystallization, rheological properties and foaming behavior were studied. PTFE L-5 and PTFE JH-220 powders showed good dispersion in the PBS matrix, and PTFE FA-500 powder underwent fibrillation during the melt blending process. All three PTFE powders gradually increased the crystallization temperature of PBS from 78.2 to 91.8 â„ƒ and the crystallinity from 45.6 to 61.7% without apparent changes in the crystal structure. Rheological results revealed that PBS/PTFE composites had a higher storage modulus, loss modulus, and complex viscosity than those of pure PBS. In particular, the complex viscosity of the PBS/P500 composite increased by an order of magnitude in the low-frequency region. The foamed structure of PBS was obviously improved by adding PTFE powder, and the effect of fibrillated PTFE FA-500 was the most remarkable, with a pore mean diameter of 5.46 µm and a pore density of 1.86 × 109 cells/cm3 (neat PBS foam: 32.49 µm and 1.95 × 107 cells/cm3). Moreover, PBS/P500 foam always guarantees hydrophobicity.

Fibrous form-stable phase change materials with high thermal conductivity fabricated by interfacial polyelectrolyte complex spinning.

Polyethylene glycol (PEG)-based composite phase change materials (PCMs) containing hydroxylated boron nitride (BN-OH), cellulose nanofiber (CNF), and chitosan (CS) were prepared by the method of interfacial polyelectrolyte complex spinning, based on in-situ ionic cross-linking between CNF and CS. The wrapping effect of cross-linked CNF/CS networks and the strong interfacial interactions contributed to superior shape-stability throughout the phase change process. Furthermore, the homogeneously dispersed BN-OHs was beneficial to the construction of the continuous thermal conductive paths, and the excellent interfacial interactions between BN-OH and the matrix would lower the heat loss caused by phonon scattering in the interface. As a result, the thermal conductivity of the PCMs containing 47.5 wt% BN-OH reached 4.005 W/mK, which was 22.56 times higher than that of the pure PEG. Combined with the excellent thermal reliability and thermal stability, the form-stable PCMs showed a promising application potential in the fields of electronic cooling or temperature-adaptable textiles.

Hierarchical Assembly of Nanocellulose into Filaments by Flow-Assisted Alignment and Interfacial Complexation: Conquering the Conflicts between Strength and Toughness.

Filaments comprising solely cellulose nanofibrils (CNFs) have been fabricated by flow-assisted assembling, where the strength can be improved greatly with the sacrifice of toughness. Inspired by the architecture of natural nacre and plant cell wall, the combined technique of convergent microfluidic spinning and in situ interfacial complexation between CNF and chitosan molecules was used to construct the filaments with hierarchical assembly of highly oriented CNFs locked by chitosan complexes, showing simultaneous enhancements of strength and toughness. In specific, the best performing filament exhibited a toughness of 88.9 kJ/m3 and a tensile strength of 1289 MPa because of the strong interfacial complexation interactions between CNFs and chitosan molecules. The tensile strength was further raised to 1627 MPa when the filaments were cross-linked synergistically by using Ca2+, surpassing the reported values in the literature. Molecular dynamics simulations revealed the possible fracture mechanism of the filaments under tension. With excellent mechanical performance and biocompatibility, the resulting CNF/chitosan filament system showed a promising application potential as nonabsorbable surgical sutures. The demonstrated spinning technology also offered a new avenue for the fabrication of high-performance filaments.

Highly Efficient Removal of Methylene Blue Dye from an Aqueous Solution Using Cellulose Acetate Nanofibrous Membranes Modified by Polydopamine.

A new type of deacetylated cellulose acetate (DA)@polydopamine (PDA) composite nanofiber membrane was fabricated by electrospinning and surface modification. The membrane was applied as a highly efficient adsorbent for removing methylene blue (MB) from an aqueous solution. The morphology, surface chemistry, surface wettability, and effects of operating conditions on MB adsorption ability, as well as the equilibrium, kinetics, thermodynamics, and mechanism of adsorption, were systematically studied. The results demonstrated that a uniform PDA coating layer was successfully developed on the surface of DA nanofibers. The adsorption capacity of the DA@PDA nanofiber membrane reached up to 88.2 mg/g at a temperature of 25 °C and a pH of 6.5 after adsorption for 30 h, which is about 8.6 times higher than that of DA nanofibers. The experimental results showed that the adsorption behavior of DA@PDA composite nanofibers followed the Weber's intraparticle diffusion model, pseudo-second-order model, and Langmuir isothermal model. A thermodynamic analysis indicated that endothermic, spontaneous, and physisorption processes occurred. Based on the experimental results, the adsorption mechanism of DA@PDA composite nanofibers was also demonstrated.

Dual super-amphiphilic modified cellulose acetate nanofiber membranes with highly efficient oil/water separation and excellent antifouling properties.

Along with increasing oily, industrial wastewater and seawater pollution, oil spills-and their clean-up via the separation of oil and water-are still a worldwide challenge. Aiming to fabricate an oil/water separation membrane with excellent comprehensive performance, we report here a new type of multifunctional deacetylated cellulose acetate (d-CA) membrane. The cellulose acetate (CA) nanofiber membranes are fabricated by electrospinning and then deacetylated to obtain the d-CA nanofiber membranes, which are super-amphiphilic in air, oleophobic in water, and super-hydrophilic in oil. The multifunctional d-CA nanofiber membranes can be used as water-removal substances for oil/water mixtures, as well as emulsified oil/water and oil/corrosive aqueous systems, with gravity as the only needed driving force. The d-CA nanofiber membranes possess the highest separation flux, reaching up to 38,000 L/m2·h, and the highest separation efficiency, reaching up to 99.97 % for chloroform/water mixtures under the force of gravity. In fact, the separation flux was several times higher than that of commercial CA (c-CA) membranes. The excellent anti-pollution and self-cleaning abilities endow the membranes with powerful cyclic stability and reusability. The d-CA nanofiber membranes show great application prospects in chemical plants, textile mills, and the food industry, as well as offshore oil spills, to separate oil from water.

Fabrication of bimodal open-porous poly (butylene succinate)/cellulose nanocrystals composite scaffolds for tissue engineering application.

The design of porous tissue engineering scaffold with multiscale open-pore architecture (i.e., bimodal structure) promotes cell attachment and growth, which facilitates nutrient and oxygen diffusion. In this study, a porous poly (butylene succinate) (PBS)/cellulose nanocrystals (CNCs) composite scaffold with a well-defined controllable bimodal open-pore interconnected structure was successfully fabricated. The bimodal open-porous scaffold architecture was designed by synergistic control of temperature variation and a two-step depressurization in a supercritical carbon dioxide (Sc-CO2) foaming process. The microstructure and properties of the bimodal open-porous PBS/CNCs scaffold, such as morphology, open porosity, hydrophilic and degradation performance, and mechanical compression properties, were analyzed. In the experiments, the scaffold with unimodal pore structure was used for comparison. The results showed that the bimodal open-porous PBS5 scaffold displayed a well-defined bimodal open-pore structure composed of large pore (~68.9 µm in diameter) and small pore (~11.0 µm in diameter), with a high open porosity (~95.2%). In addition, the scaffolds exhibited good mechanical compressive properties (compressive strength of 2.76 MPa at 50% strain), hydrophilicity (water contact angle of 71.7 °C) and in vitro degradation rate. Moreover, in vitro biocompatibility was determined with NIH-3T3 fibroblast cells using MTT assay and live/dead cell viability assay. Results indicated that the obtained bimodal open-porous scaffolds had a good biocompatibility and the viability of cells grown on the scaffolds reached up to 98% after 7th day of culture. Therefore, our work provides new insights into the use of biodegradable polymeric composite scaffolds with bimodal open-pore structure and balanced properties in tissue engineering.

Highly Durable Superhydrophobic Polymer Foams Fabricated by Extrusion and Supercritical CO2 Foaming for Selective Oil Absorption.

The severe water contamination caused by oil leakage is calling for low-cost and high-performance absorbent materials for selective oil removal. In this study, a scalable green method was proposed to produce polypropylene (PP)/poly(tetrafluoroethylene) (PTFE) composite foams via conventional processing techniques including twin-screw extrusion and supercritical carbon dioxide foaming. To produce the superhydrophobic foam, micro- and nanosized PTFE particles were melt blended with PP and subsequently foamed. Ascribed to the nanofibrillation of microsized PTFE during processing, the fabricated foam exhibited a special highly porous structure with PTFE nanofibrils and nanoparticles uniformly distributed on the pore surfaces within the PP matrix, which resulted in a remarkably high water contact angle of 156.8° and a low contact angle hysteresis of 1.9°. Unlike traditional surface-modified superhydrophobic absorbers, the foams prepared are entirely superhydrophobic, which means that they remain superhydrophobic when being fractured or cut. Moreover, they are highly durable and maintained the superhydrophobicity when subjected to ultrasonication and mechanical sanding. When used in selective oil absorption, the durable foams exhibited excellent absorption efficiency and high stability in repetitive and long-term use. These advantages make the PP/PTFE foam a promising superabsorbent material for water remediation.

Highly Stretchable and Biocompatible Strain Sensors Based on Mussel-Inspired Super-Adhesive Self-Healing Hydrogels for Human Motion Monitoring.

Integrating multifunctionality such as adhesiveness, stretchability, and self-healing ability on a single hydrogel has been a challenge and is a highly desired development for various applications including electronic skin, wound dressings, and wearable devices. In this study, a novel hydrogel was synthesized by incorporating polydopamine-coated talc (PDA-talc) nanoflakes into a polyacrylamide (PAM) hydrogel inspired by the natural mussel adhesive mechanism. Dopamine molecules were intercalated into talc and oxidized, which enhanced the dispersion of talc and preserved catechol groups in the hydrogel. The resulting dopamine-talc-PAM (DTPAM) hydrogel showed a remarkable stretchability, with over 1000% extension and a recovery rate over 99%. It also displayed strong adhesiveness to various substrates, including human skin, and the adhesion strength surpassed that of commercial double-sided tape and glue sticks, even as the hydrogel dehydrated over time. Moreover, the DTPAM hydrogel could rapidly self-heal and regain its mechanical properties without needing any external stimuli. It showed excellent biocompatibility and improved cell affinity to human fibroblasts compared to the PAM hydrogel. When used as a strain sensor, the DTPAM hydrogel showed high sensitivity, with a gauge factor of 0.693 at 1000% strain, and was capable of monitoring various human motions such as the bending of a finger, knee, or elbow and taking a deep breath. Therefore, this hydrogel displays favorable attributes and is highly suitable for use in human-friendly biological devices.

Synthesis of DOPO-HQ-functionalized graphene oxide as a novel and efficient flame retardant and its application on polylactic acid: Thermal property, flame retardancy, and mechanical performance.

The fabrication of biodegradable polymer nanocomposites with improved flame retardancy has been an urgent task in practical because of the huge benefits of biodegradable polymers. In this work, 10-(2,5-dihydroxyl phenyl)-9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO-HQ)-functionalized graphene oxide (GO) (FGO-HQ) was used as a novel and highly efficient flame retardant (FR) to improve the flame retardancy of polylactide (PLA) nanocomposites. Contributed by the bi-phase flame retardant action, including the physical barrier char in solid phase and the decreased flammable volatiles in gas phase, the resultant PLA/FGO-HQ nanocomposites presented excellent flame resistance at the loading of 6 wt% FR: UL-94 reached V-0 rating; peak heat release rate (PHRR) and total heat release (THR) decreased by 24.0% and 43.0%, respectively; smoke production rate (SPR) and total smoke release (TSR) decreased by 46% and 83%, respectively. For further confirming its flame-resistance mechanism, thermogravimetric analysis/infrared spectrometry (TG-IR) and Fourier transform infrared spectra (FT-IR), scanning electron microscope (SEM), and Raman spectroscopy were employed. Results indicated that the incorporation of FGO-HQ can effectively reduce the evaporation of flammable gaseous product in gas phase through quenching free radicals. Meanwhile, graphitized carbons are formed in the residual char and PLA/FGO-HQ sample can achieve a good thermal stability in the combustion with phosphorus-containing compounds and aromatic structure in the solid phase. Furthermore, the tensile strength of PLA nanocomposites presented good mechanical properties with the addition of FR as well. These results suggested that the incorporation of FGO-HQ FR not only improve the flame retardancy and thermal stability of biodegradable polymer nanocomposites but also without sacrificing their mechanical properties.

Establishment of a highly efficient flame-retardant system for rigid polyurethane foams based on bi-phase flame-retardant actions.

Rigid polyurethane foam (PU), one of the most promising wall insulation materials, exhibits high flammability and fire risk. In this work, PU/EG/HQ composites with highly effective flame retardancy were fabricated by adding two kinds of flame retardants, expandable graphite (EG) and 10-(2,5-dihydroxyphenyl)-10-hydro-9-oxa-10-phosphorylphenanthrene-10-oxide (DOPO-HQ), during the synthesis of polyurethane. Thermal stability and flammability were evaluated using the limiting oxygen index (LOI), thermogravimetric analysis (TGA), UL-94 vertical flame results, and cone colorimeter tests. The as-synthesized PU/EG/HQ composites showed a high LOI value, a maximum peak heat release rate (PHRR) value which was decreased by 58.5% and an increased char yield at 800 °C. They also achieved UL-94 V-0 classification. SEM and Raman spectra indicated that the "worm-like" intumescent char layer with a graphitized structure and the formed viscous liquid film were vital factors in the enhancement of the flame retardancy of polyurethane foam in the condensed phase. TG-IR results show that the release of toxic volatiles and flammable gases from the PU/EG/HQ samples was remarkably decreased compared with the release from pure PU. This work associates a gas-solid biphase flame retardancy mechanism with the incorporation of two types of flame retardant and presents an effective method for the synthesis of bi-phase flame-retardant polymers.

Superior Impact Toughness and Excellent Storage Modulus of Poly(lactic acid) Foams Reinforced by Shish-Kebab Nanoporous Structure.

Poly(lactic acid) (PLA) foams, with the combination of shish-kebab and spherulite nanoporous structure in skin and core layer respectively, was prepared using a novel technique comprising loop oscillating push-pull molding (LOPPM) and supercritical carbon dioxide low-temperature foaming process (SC-CO2LTFP). The foams present superior impact toughness which is 6-fold higher than that of neat PLA, and no significant decrease was observed for the storage modulus. Moreover, SC-CO2LTFP at soaking temperature ranging from 110 to 150 °C were performed to determine the evolution of pore morphology. The ultratough and supermoduli are unprecedented for PLA, and are in great need for broader applications.

Molecular Beacon Nano-Sensors for Probing Living Cancer Cells.

Heterogeneities and oncogenesis essentially result from proteomic disorders orchestrated by changes in DNA and/or cytoplasmic mRNA. These genetic fluctuations, however, cannot be decoded through conventional label-free methods (e.g., patch clamps, electrochemical cellular biosensors, etc.) or morphological characterization. Molecular beacons (MBs) have recently emerged as efficient probes for interrogating biomarkers in live cancer cells. MBs hybridize with their intracellular targets (e.g., mRNAs, DNAs, or proteins), emitting a fluorescent signal that can be quantified and correlated with the expression levels of their targets. In this review we discuss MB probes with different delivery platforms for intracellular probing as well as novel MB designs for detecting a variety of targets in living cancer cells. Finally, we describe current trends in MB-based intracellular biosensors.

Heteroatom-doped carbon dots: synthesis, characterization, properties, photoluminescence mechanism and biological applications.

Heteroatom-doped carbon dots (CDs), due to their excellent photoluminescence (PL) properties, attracted widespread attention recently and demonstrated immense promise for diverse applications, particularly for biological applications. The objective of this feature article is to provide a comprehensive overview of the recent progress in the research and development of heteroatom-doped CDs and a detailed description of the influence of single or co-doping heteroatoms on their PL behavior. The most recent understanding and critical insights into the PL mechanism of heteroatom-doped CDs are also highlighted. Moreover, potential bio-related applications of heteroatom-doped CDs in biosensing, bioimaging, and theranostics are also reviewed. This state-of-the-art review will provide a platform for understanding the intricate details of heteroatom-doped CDs, a summary of the latest progress in the field, and related applications in biology and is expected to inspire further developments in this exciting class of materials.

Comparatively Thermal and Crystalline Study of Poly(methyl-methacrylate)/Polyacrylonitrile Hybrids: Core-Shell Hollow Fibers, Porous Fibers, and Thin Films.

The polyacrylonitrile/polymethyl-methacrylate (PMMA/PAN) porous fibers, core-shell hollow fibers, and porous thin films are prepared by coaxial electrospinning, single electrospinning, and spin-coating technologies, respectively. The different morphologies arising from different processes display great influences on their thermal and crystalline properties. The adding of PMMA causes porous structure due to the microphase-separation structure of immiscible PMMA and PAN phases. The lower weight loss, higher degradation temperature, and glass-transition temperatures of porous thin films than those of porous fibers and core-shell hollow fibers are obtained, evidencing that the polymer morphologies produced from the different process can efficiently influence their physical properties. The orthorhombic structure of PAN crystals are found in the PMMA/PAN porous thin films, but the rotational disorder PAN crystals due to intermolecular packing are observed in the PMMA/PAN porous fibers and core-shell hollow fibers, indicating that different processes cause different types of PAN crystals.