Self-assembled Microspheres Research Articles

Multiresponsive Color-Changing and Tough Hydrogels Enabled by Self-Assembled Epoxy Oligomer Microspheres.

The fabrication process of hydrogels often incorporates various strategies to achieve multiple responses and enhance strength, which always make the procedure complex and even hinder the incorporation. Here, we develop a facile and flexible method to simultaneously achieve multiresponsive color-changing and tough properties in hydrogels by introducing epoxy oligomer microspheres (DEPMS) to hydrophobic association (HA) hydrogels. DEPMS is responsive to both pH and solvents, showing color changes due to conversion to a conjugated structure. The obtained DEPMS composite hydrogels could demonstrate diverse color-changing patterns by simply adjusting the components and pH of the solvents. Meanwhile, amphiphilic DEPMS helps to disperse hydrophobic regions of the HA hydrogel, resulting in more uniform cross-linking and thereby contributing to the enhanced mechanical properties. The tensile strength and toughness of the composite hydrogels could be easily adjusted and reach 1.00 MPa and 11.18 MJ m-3, respectively. This work provides an approach to the design of multiple responsive and tough hydrogels while offering insights into the recycling of waste epoxy resins.

Synthesis of Self-Assembled Mesoporous ZnO Microspheres Designed for Microwave-Assisted Photocatalytic Degradation of Tetracycline.

Microwave-assisted photocatalysis offers a novel approach for degrading antibiotics, while the mechanism of enhancement of microwave-induced photocatalysis remains poorly understood. In this study, tetracycline (TC) was degraded using the method of microwave-assisted photocatalysis with a ZnO catalyst, which was synthesized by the combination of hydrothermal and calcination methods. The self-assembled mesoporous ZnO catalyst exhibited superior catalytic activity in degrading TC. It is found that the degradation efficiency of TC by the ZnO catalysts with microwave-assisted photocatalysis is 4.27 times higher than that of photocatalysis alone. Of particular significance, we found that the optical absorption range of ZnO increased and the band gap decreased when microwave was introduced into the photocatalytic system. Semi-in situ photochemical tests demonstrated that more photogenerated electron-hole pairs were detected under microwave, thus further improving the photocatalytic activity of ZnO. The separation efficiency and charge transfer efficiency of photogenerated electron-hole pairs also improved due to the increase of oxygen vacancies in the synergistic effect. Meanwhile, h+ and ·OH were the main active species in the degradation system. The mechanism of microwave-induced photocatalysis is illustrated, and an efficient way for degrading antibiotic is provided in this work.

CeO2 anchored in VO2@C rambutan-like microsphere achieving advanced zinc storage

Low-cost and high-safety aqueous zinc ion batteries (AZIBs) show great potential in energy storage for the grid. We propose a strategy to construct the self-assembled microspheres with the cerium oxide nanocrystals anchored on B-phase vanadium dioxide nanobelts, which are encapsulated by carbon (CVC), as cathode for high capacity and cycle stability of AZIBs. The rambutan-like structure with large specific surface area provides more active sites for the overall improvement of reaction kinetics; the carbon layer relieves vanadium dioxide from dissolving in the electrolyte while enhancing electron transfer rate; and electrocatalytic activity of cerium oxide accelerates redox reaction to enhance the performance of the cells. Consequently, the CVC electrode exhibits excellent electrochemical properties, including a reversible specific capacity (490 mAh g−1 at 0.1 A g−1), incredible cycle (84 % capacity retention after 1000 cycles at 5 A g−1). The excellent performance demonstrates the correctness of the combined internal and external modification strategy, while the simple hydrothermal method and inexpensive raw materials point to a new direction for the large-scale preparation of high-performance aqueous zinc ion batteries.

Plasmonic structurally colored surfaces with metal film over microsphere lattices

Structural coloring through plasmonic nanostructures involves the manipulation of light interaction with nanostructured metallic surfaces to selectively reflect specific spectral ranges within the visible spectrum. Unlike conventional pigments that absorb light based on their chemical properties, plasmonic nanostructures achieve color through their physical configuration. This study investigates the potential of generating plasmonic structural colors by utilizing self-assembled colloidal microsphere lattices that are coated with thin metal films. Finite-Difference Time-Domain (FDTD) simulations are employed on realistic models to analyze the optical reflectance of dielectric microsphere lattices ranging in sizes from 300 to 700 nm, coated with varying thicknesses (20–200 nm) of different metals (Al, Ag, Au). The reflectance spectra are then translated into specific colors using a software algorithm, with the color representations plotted on CIE1931 diagrams. Furthermore, to validate the theoretical findings, two-dimensional polystyrene microsphere arrays coated with Au and Ag films are prepared, and their reflectance spectra and color images are examined. The resulting plasmonic colors can be adjusted by altering the sphere size, the type of metal used, and the thickness of the coating, demonstrating their potential for diverse color-based applications.

3D Surface-Enhanced Raman Scattering Substrate Based on an Array of Self-Assembled Au@SiO2 Microspheres

A quasi-periodic array of 3D gold-nanoparticle-capped SiO2 microspheres (Au@SiO2) was designed and prepared with a facile approach to enhance the Raman signal intensity of adsorbed biomolecules. Through adjusting the thickness and annealing of Au thin films initially deposited on arrays of self-assembled SiO2 microspheres, we were able to control the diameter of Au nanoparticles and their interparticle spacing to produce two types of plasmonic near-field hot spots, locating at the gaps of such densely arranged Au nanoparticles on individual SiO2 microspheres and in the gap regions of neighboring SiO2 microspheres, respectively. Such double near-field enhancement mechanism leads to a surface-enhanced Raman scattering (SERS) enhancement factor up to 3 × 106 for Rhodamine 6G molecules. The SERS signal intensity was highly uniform with a relative standard deviation of 4.5%. This 3D SERS substrate has significant potential for various applications in the field of SERS detection of analytes and wearable biosensing.

Enhanced Li-O2 battery performance using NiS/MoS2 heterostructure by building internal electric field to promote the one-electron oxygen reduction/oxidation

Electrocatalysts with appropriate electron coupling toward LiO2 intermediates can exhibit superior oxygen reduction/evolution reaction kinetics in Li-O2 batteries (LOBs). In this work, a charge redistribution strategy has been developed by constructing NiS/MoS2 heterostructure nanosheet self-assembled hollow microspheres with an internal electric field to regulate the interaction with LiO2 and then improve the electrochemical performance of LOBs. Density functional theory calculations and physicochemical characterizations reveal that the difference of work functions between NiS and MoS2 promotes the electron redistribution in heterointerface via built-in electrical field, leading to increased electron density of interfacial Ni atom, thereby enhancing its electron coupling toward LiO2 intermediates and promoting one-electron oxygen reduction/oxidation reaction kinetics. As a result, the NiS/MoS2-based LOBs exhibit evidently higher discharge capacity and much better cycling performance than the batteries using NiS and MoS2. This work provides a reliable charge redistribution strategy induced by build-in electric field to design efficient catalysts for LOBs.

Self-assembled LaCoO3/Ag3PO4 nanocomposite with enhanced anti-bacterial performance

Bacteria are mostly everywhere, some of them affect health safety of human beings, plants and animals all the time. Photocatalytic antibacterial technology has entered people's field of vision due to their high-efficiency and sustainability. In this study, LaCoO3 precursors were prepared by solvothermal synthesis, and then calcined to obtain self-assembled LaCoO3 microspheres. Subsequently, LaCoO3/Ag3PO4 microspheres were synthesized by in-situ precipitation method. Compared with pure LaCoO3 microspheres, the introduction of Ag3PO4 nanoparticles can effectively enhance the antibacterial performance of LaCoO3/Ag3PO4 nanocomposites. LaCoO3/Ag3PO4 nanocomposites' Minimum Inhibitory Concentrations (MICs) against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) were tested to be 0.1 mg mL−1 and 0.15 mg mL−1, respectively. Under visible light irradiation for 20 min, the antibacterial rate of nanocomposites against E. coli and S. aureus was 99.9 % and 98.3 %, correspondingly. This can be attributed to the fact that LaCoO3/Ag3PO4 heterojunction significantly improves the responsiveness of visible light, carrier separation and migration efficiency of LaCoO3, which promotes the nanocomposite to produce a large number of ROS under visible light. In addition, LaCoO3/Ag3PO4 nanocomposites had a strong oxidation effect on glutathione (GSH), resulting in the failure of the antioxidant defense system of bacteria. Also, the release of Ag+ and plasma effect of Ag are also important reasons for the high antibacterial performance of LaCoO3/Ag3PO4 nanocomposites. The photoresponse of LaCoO3-based nanomaterials under visible light is effectively improved by constructing heterojunctions, the separation efficiency of photogenerated electron-hole pairs is increased, and the carrier transport is accelerated, thus achieving high efficiency and broad spectrum antibacterial effect. This research shows that LaCoO3 nanocomposites can be used as a prospective photocatalytic antibacterial material, enhances the value of practical applications.

Robust mechanical strength and high colorfastness of amorphous photonic crystals on fabrics with durable antibacterial and anti-static properties

The technique of utilizing structural color dyeing presents a sustainable and energy-conserving approach to textile dyeing. However, the coating with structural coloration always exhibited cracks and inadequate colorfastness attributed to the presence of capillary tension. In this study, we employed a hydrophilic silane called 3-aminopropyltriethoxysilane (KH550) to chemically modify the fabric. This method endowed the fabric with reactive amino groups, thereby augmenting the interfacial bonding strength between polydopamine (PDA)@SiO2@Ag+/Ag NPs and the fabric substrate through metal coordination and covalent bonds. Additionally, by utilizing catechol complexation, we successfully loaded Ag ions onto the PDA coating of composite microspheres. These Ag ions acted as linkers during self-assembly of microspheres. The active amino groups on the surface of chemically modified cotton fabric reacted with PDA at a specific temperature, resulting in the formation of robust covalent bonds simultaneously. The resulting fabric demonstrated excellent water resistance as well as efficient antibacterial and anti-static properties, which were confirmed through various mechanical tests such as washing, folding, and rubbing experiments. This research presents an innovative approach for creating durable structural colored fabrics with multifunctional properties based on metal coordination and covalent bonds that can be effectively applied in textile printing and dyeing.

Ultra-low detection limit self-sensing nanocomposites with self-assembled conductive microsphere arrays for asphalt pavement health monitoring

Accurately monitoring micro-level strain within pavements poses a significant challenge in contemporary road engineering, limiting the effectiveness of early-stage pavement health diagnostics. Addressing this critical gap, this study introduces an innovative ultra-low detection limit sensor, specifically designed for intricate pavement health monitoring. It pivots on the unique structural design of a well-ordered 3D conductive network, where the self-assembly effect of microsphere arrays ingeniously mitigates the prevalent issue of nanofiller agglomeration within polymer matrices. The study highlights the significant role of carbon nanotubes (CNTs) length in shaping the structure of conductive networks, revealing that while longer CNTs lead to less uniform microsphere assemblies, they significantly enhance the bridging effect crucial for conductive pathways. To balance these traits, surface chemical modifications were strategically applied, effectively enhancing microsphere organization and dispersion, thereby elevating the conductive and sensing performance. The optimized sensor stands out for the ultra-low detection limit of 0.0005% (5 uε), significantly surpassing those of current strain sensors. Moreover, it exhibits remarkable sensitivity, evidenced by a gauge factor of 13.2, along with swift response and recovery times of 19 ms and 26 ms respectively, and impressive durability, enduring over 100,000 loading-unloading cycles. Field tests under diverse vehicular loads and speeds further validate the sensor's accuracy in capturing dynamic responses within pavement structures, a key factor in proactive pavement maintenance and management. Hence, this advancement shows promise in contributing to the development of safer and more resilient road networks, playing a beneficial role in the significant progress of intelligent transportation and sustainable infrastructure management.

Influence of Cell Characteristics on the Construction of Structural Color Layers on Wood Surfaces

When utilizing microspheres to construct structural color layers on wood surfaces, the cellular structure of wood can influence the self-assembly of microspheres and the resulting structural color layers. To investigate this influence, seven types of wood were selected in this study, and structural color layers were constructed on their surfaces. A comparative analysis was conducted on the color production and macro and micro morphologies of the structural color layers on different wood surfaces, along with an examination of the types and causes of surface defects. The study found that when a microsphere-containing emulsion was applied to a wood surface, the emulsion tended to flow along the vessels of hardwood and the tracheids of softwood. Overflow or seepage of the emulsion could lead to a reduction in the number of microspheres per unit area, resulting in uneven thickness and uneven color generation of the structural color layers. Although the structural color layers on different wood exhibited the same color, there were variations in their tones, appearance, and morphology. Defects such as minor bumps and pits were present on the structural color layers. Bump defects might originate from microsphere encapsulation of fiber bundles or the displacement of air within vessel lumens by emulsion, while pits were mainly caused by the inflow of emulsion into the vessel lumens. This study clarified the influence of wood surface cells, particularly vessels and tracheids, on the construction and color production of structural color layers, providing support for the controllable modification of wood surfaces using structural colors.

Carbon-doped Bi2MoO6 nanosheet self-assembled microspheres for photocatalytic degradation of organic dyes

Abstract In this paper, carbon-doped Bi2MoO6 (C-Bi2MoO6) nanosheet self-assembled microspheres were prepared by using the solvothermal-calcination route to improve the photocatalytic activity of Bi2MoO6. The characterization results of x-ray diffractometry, Fourier transform infrared spectrometry, Raman scattering, scanning electron microscopy, transmission electron microscopy, BET specific surface area test, and x-ray photoelectron spectrometry indicated that C replaced the O2− anion in the Bi2MoO6 lattice, thinning the nanosheets, decreasing the size of the microspheres, and increasing the specific surface area of the Bi2MoO6. Ultraviolet–visible diffuse reflectance spectroscopy, photoluminescence, electrochemical impedance spectroscopy, transient photocurrent, and linear sweep voltammetry (LSV) spectroscopy demonstrated that the carbon doping reduced the band gap energy, raised the conduction band, and enhanced the photogenerated electron–hole pairs separation efficiency of Bi2MoO6. Benefiting from these favorable changes, the C-Bi2MoO6 microspheres prepared at a molar ratio of C to Bi of 4 (4C-Bi2MoO6) exhibited the highest photocatalytic activity, and the photocatalytic degradation rate constant of rhodamine B by 4C-Bi2MoO6 microspheres was almost 2.26 times that by pristine Bi2MoO6 under simulated solar light. 4C-Bi2MoO6 microspheres (0.2 g/L) presented excellent photocatalytic performance toward RhB (20 mg/L) at pH value 1 and could remove 98.31% of the RhB within 120 min. In addition, 4C-Bi2MoO6 microspheres also possessed a high photocatalytic activity toward methylene blue and tetracycline. 4C-Bi2MoO6 microspheres assembled from thin nanosheets can be used as effective photocatalysts to degrade toxic organic molecules from wastewater.

Multifunctional self-assembled adsorption microspheres based on waste bamboo shoot shells for multi-pollutant water purification

In this study, multilayer self-assembled multifunctional bamboo shoot shell biochar microspheres (BSSBM) were prepared, in which bamboo shoot shell biochar was used as the carrier, titanium dioxide as the intermediate medium, and chitosan as the adhesion layer. The adsorption behavior of BSSBM on heavy metals Ag(I) and Pd(II), antibiotics, and dye wastewater was systematically analyzed. BSSBM shows a wide range of adsorption capacity. BSSBM is a promising candidate for the purification of real polluted water, not only for metal ions, but also for Tetracycline (TC) and Methylene Blue (MB). The maximum adsorption amounts of BSSBM on Pd(II), Ag(I), TC and MB were 417.3 mg/g, 222.5 mg/g, 97.2 mg/g and 42.9 mg/g, respectively.The adsorption of BSSBM on Pd(II), MB and TC conformed to the quasi-first kinetic model, and the adsorption on Ag(I) conformed to the quasi-second kinetic model. BSSBM showed remarkable selective adsorption capacity for Ag(I) and Pd(II) in a multi-ion coexistence system. BSSBM not only realized the high value-added utilization of waste, but also had the advantages of low cost, renewable and selective adsorption. BSSBM demonstrated its potential as a new generation of multifunctional adsorbent, contributing to the recovery of rare/precious metals and the treatment of multi-polluted water.

Microsphere photolithography with dynamic angular spectra control for metasurface fabrication.

Microsphere photolithography (MPL) is a promising technique for cost-effective fabrication of large-scale metasurfaces. This approach generates an array of photonic jets by the collimated illumination of self-assembled microspheres. The photonic jets can be precisely steered within the unit cell defined by each microsphere by changing the angle of incidence. This allows for the creation of complex metasurface element geometries. Computer controlled articulation of the substrate relative to a static UV source allows the direct-write of different metasurface elements. However, this is time-consuming and requires registration between each exposure for complex features. This paper investigates a single exposure method with the dynamic continuous angle of incidence control provided by a Digital Micromirror Device (DMD) in the front Fourier plane of the projection system. The grayscale values of the DMD pixels can be adjusted to provide optical proximity correction. Larger patterns can be achieved by scanning the substrate relative to the exposure beam. This approach is demonstrated with the creation of hierarchical patterns. This work greatly simplifies the MPL exposure process for complex resonators and provides potential for full light field control.

Innovative Application of Subwavelength Periodic Polystyrene Microspheres as Saturable Absorbers in Nonlinear Optics

Polystyrene (PS) possesses numerous remarkable properties like high transparency, impressive mechanical strength, and a large specific surface area, making it an excellent mask plate or template for the preparation of anti-opal structures. Moreover, it should be noted that PS also exhibits exceptional nonlinear properties due to the subwavelength periodic configuration. In this paper, a self-assembled PS microsphere photonic crystal saturable absorber (PSM-SA) has been proposed and fabricated. It exhibits impressive properties including high stability, high damage threshold, high refractive index, and large specific surface area. It is suggested that the periodic structure of PS in the film has a significant impact on the photonic band gap, resulting in excellent adjustable optical nonlinear characteristics. By integrating PSM-SA into a self-built ring fiber laser system, a Q-switched laser with a pulse width of approximately 2 μs and a repetition rate of 40 kHz at a wavelength of 1562 nm is obtained. These findings demonstrate its potential for enabling efficient and adjustable nonlinear optical functionalities in various optical devices, contributing to the expanding realm of PS microsphere photonic crystals and their significant impact on advancing nonlinear optics technology.

Combined experimental and DFT study on the adsorption of congo red dye using self-assembled hierarchical microspheres of lanthanum hydroxide

Self-assembled hierarchical microspheres of lanthanum hydroxide (La(OH)3) were used to investigate the adsorption of the azo-dye Congo Red (C.R.) in an aqueous medium. The versatile coordination chemistry of lanthanum ions makes them very efficient in adsorption processes involving organic ligands. The microspheres were synthesized using the reaction-diffusion framework (RDF) at ambient temperature, which consists of diffusing a concentrated ammonia solution onto an agar hydrogel matrix containing the dissolved lanthanum salt. The microspheres, which emerged with distinct Liesegang bands ranging in size from ∼300 nm to ∼70 µm, demonstrated rapid adsorption, reaching equilibrium within 15 min, with optimal adsorption of 395 mg g–1 at pH 6 and 30 °C. The kinetic and thermodynamic data were analyzed and fitted to a pseudo-second-order equation and the Sips model. The adsorption mechanism, driven by the dye's structure, the adsorbent's surface chemistry, and the medium, involves complex interplays of electrostatic attractions, physisorption, and chemisorption, with water playing a pivotal role. The positive enthalpy of adsorption extracted from a Sips isotherm, diverging from Langmuir behavior, and FTIR spectral comparisons pre- and post-adsorption provide empirical insights. Density functional theory (DFT) calculations, complemented by implicit solvation models, reveal significant solvation effects on the adsorption enthalpy of the sulfonate group of C.R. on the La(OH)3 surface, highlighting the solvent's vital role. The adsorption enthalpy of +62.63 kJ mol–1 closely aligns with the primary termination of the lanthanum hydroxide surface by water molecules. Remarkably, the bond length between the surface lanthanum and water's oxygen undergoes a significant shift when bonded to the sulfonate group. This study offers a deeper understanding of C.R. dye adsorption dynamics, emphasizing both experimental findings and theoretical insights, underscoring the complex interplay of forces and the central role of water in the process.

Coloration on Bluish Alginate Films with Amorphous Heterogeneity Thereof.

Using sodium alginate (Alg) aqueous solution containing indigo carmine (IdC) at various concentrations we characterized the rippled surface pattern with micro-spacing on a flexible film as intriguing bluish Alg-IdC iridescence. The characterization was performed using Fourier-transform infrared spectroscopy, ultraviolet-visible spectroscopy, field emission scanning electron microscopy, atomic force microscopy, electron microscopy, differential scanning calorimetry, thermogravimetric analysis, X-ray diffraction analysis, and photoluminescence detection. The edge pattern on the film had a maximum depth of 825 nm, a peak-to-peak distance of 63.0 nm, and an average distance of 2.34 nm. The center of the pattern had a maximum depth of 343 nm and a peak-to-peak distance of 162 nm. The pattern spacing rippled irregularly, widening toward the center and narrowing toward the edges. The rippled nano-patterned areas effectively generated iridescence. The ultraviolet absorption spectra of the mixture in the 270 and 615 nm ranges were the same for both the iridescent and non-iridescent film surfaces. By adding Ag+ ions to Alg-IdC, self-assembled microspheres were formed, and conductivity was improved. Cross-linked bluish materials were immediately formed by the addition of Ca2+ ions, and the film was prepared by controlling their concentration. This flexible film can be used in applications such as eco-friendly camouflage, anti-counterfeiting, QR code materials for imaging/sensing, and smart hybrid displays.

Bi/Mn-Doped BiOCl Nanosheets Self-Assembled Microspheres toward Optimized Photocatalytic Performance.

Doping engineering of metallic elements is of significant importance in photocatalysis, especially in the transition element range where metals possess empty 'd' orbitals that readily absorb electrons and increase carrier concentration. The doping of Mn ions produces dipole interactions that change the local structure of BiOCl, thus increasing the specific surface area of BiOCl and the number of mesoporous distributions, and providing a broader platform and richer surface active sites for catalytic reactions. The combination of Mn doping and metal Bi reduces the forbidden bandwidth of BiOCl, thereby increasing the absorption in the light region and strengthening the photocatalytic ability of BiOCl. The degradation of norfloxacin by Bi/Mn-doped BiOCl can reach 86.5% within 10 min. The synergistic effect of Mn doping and Bi metal can change the internal energy level and increase light absorption simultaneously. The photocatalytic system created by such a dual-technology combination has promising applications in environmental remediation.

Click functionalized naphthalene contained polycarbazole microspheres for use in electrochromic applications

New fluorescent and electropolymerizable monomer 2-((1-(naphthalene-1-yl)-1H-1,2,3-triazole-4-yl)methoxy)-9H-carbazole (NPC) was designed via efficient click synthesis of naphthalene and carbazole moiety. NPC was characterized using 1H NMR, 13C NMR, FTIR, fluorescence, and UV–vis spectroscopy. The produced monomer was electropolymerized by electrochemical oxidation of carbazole moieties on indium tin oxide in the ACN: BFEE (2:1, v/v) where LiClO4 was used as the supporting electrolyte. The resulting polymer film PNPC depicted well-defined electrochemical properties and a low monomer oxidation potential at around 0.80 V. PNPC displayed multi-electrochromic behaviors, which have color changing from transparent to dark blue reversibly when different voltages were applied. The remarkable electrochromic behavior of the PNPC was explained in detail with the help of spectroelectrochemical studies. The PNPC film exhibited high optic contrast of 77% at 701 nm and a fast-switching time of 1.0 s. When the surface morphology was examined via scanning electron microscopy (SEM), it was determined that PNPC film formed self-assembled microspheres electrochemically. Due to their high optical contrast and stable electrochemical characteristics, these microspheres might be a desirable option as electrode materials for use in electrochromic applications.

Impact of Plasmonic and Dielectric Substrates on the Whispering-Gallery Modes in Self-Assembled Fluorescent Semiconductor Polymer Microspheres.

In this work, the impact of metallic and dielectric conducting substrates, gold and indium tin oxide (ITO)-coated glass, on the whispering gallery modes (WGMs) of semiconductor π-conjugated polymer microspheres is investigated. Hyperspectral mapping was performed to obtain the excitation-position-dependent emission spectra of the microspheres. Substrate-dependent quenching of WGMs sensitive to mode polarization was observed and explained. On a glass substrate, both transverse-electric (TE) and transverse-magnetic (TM) WGMs are quenched due to frustrated total internal reflection. On a gold substrate, however, only the TM WGMs are allowed in symmetry to leak into surface plasmons. An atomically flat gold substrate with subwavelength slits was used to experimentally verify the leakage of WGMs into the surface plasmon polaritons (SPPs). This work provides insight into the damping mechanisms of WGMs in microspheres on metallic and dielectric substrates.

Phosphate-modified cellulose/chitosan with high drug loading for effective prevention of rice leaffolder (Cnaphalocrocis medinalis) outbreaks in fields

The continuous infestation of pests has seriously affected rice growth, yield and quality. How to reduce the use of pesticides and effectively control insect pests is a bottleneck problem. Herein, based on hydrogen bonding and electrostatic interactions, we posed a novel strategy to construct emamectin benzoate (EB) pesticide loading system using self-assembled phosphate-modified cellulose microspheres (CMP) and chitosan (CS). CMP provides more binding sites for EB loading and CS coating further enhances the carrier loading capacity up to 50.75 %, which jointly imparted pesticide photostability and pH-responsiveness. The retention capacity of EB-CMP@CS in rice growth soil reached 101.56-fold that of commercial EB, which effectively improved the absorption of pesticides during rice development. During the pest outbreak, EB-CMP@CS achieved effective pest control by increasing the pesticide content in rice stems and leaves, the control efficiency of the rice leaffolder (Cnaphalocrocis medinalis) reached 14-fold that of commercial EB, and could maintain the effective pest control effect during the booting stage of rice. Finally, EB-CMP@CS-treated paddy fields had improved yields and were free of pesticide residues in the rice grain. Therefore, EB-CMP@CS achieves effective control of rice leaffolder in paddy fields and has potential application value in green agricultural production.