Poly Methyl Methacrylate Spheres Research Articles

Beetle-inspired AuNPs semi-embedded colloidal crystal chips for the highly sensitive and colored detection of chloramphenicol in foods

Inspired by the desert beetle, a novel biomimetic chip was developed to detect chloramphenicol (CP). The chip was characterized by a periodic array in which hydrophobic Au nanoparticles (AuNPs) were semi-embedded on hydrophilic polymethyl methacrylate (PMMA) spheres. Among them, the AuNPs exhibited both a localized surface plasmon resonance effect to amplify the reflected signal and a synergistic effect with PMMA spheres to create a significant hydrophilic-hydrophobic interface, which facilitated the enrichment of target CP molecules and improved sensitivity. After optimization, the chip showed direct, ultrasensitive (as low as 0.2 ng/mL), fast (5 min), and selective detection of CP with a wide concentration range extending from 0.2 ng/mL to 1000 ng/mL. During detection, color changes of the chip were observed by naked eyes without any color display equipment. The recovery of CP was between 94.65 % and 108.70 % in chicken and milk samples.

Reverse total shoulder arthroplasty with proximal bone loss: a biomechanical comparison of partially vs. fully cemented humeral stems

BackgroundThe appropriate amount of cementation at the time of reverse total shoulder arthroplasty with significant proximal bone loss or resection is unknown. Extensive cementation of a humeral prosthesis makes eventual revision arthroplasty more challenging, increasing the risk of periprosthetic fracture. We analyzed the degree of subsidence and torque tolerance of humeral components undergoing standard cementation technique versus our reduced polymethyl methacrylate (PMMA) protocol. Reduced cementation may provide sufficient biomechanical stability to resist physiologically relevant loads, while still permitting a clinically attainable torque for de-bonding the prosthesis. MethodsA total of 12 cadaveric humeri (6 matched pairs) underwent resection of 5 cm of bone distal to the greater tuberosity. Each pair of humeri underwent standard humeral arthroplasty preparation followed by either cementation using a 1.5 cm PMMA sphere at a location 3 cm inferior to the porous coating or standard full stem cementation. A 6-degrees-of-freedom (DOF) robot was used to perform all testing. Each humeral sample underwent 200 cycles of abduction, adduction, and forward elevation while being subjected to a physiologic compression force. Next, the samples were fixed in place and subjected to an increasing torque until implant-cement separation or failure occurred. Paired t-tests were used to compare mean implant subsidence versus a predetermined 5 mm threshold, as well as removal torque in matched samples. ResultsFully and partially cemented implants subsided 0.49mm (95% CI, 0.23 to 0.76 mm) and 1.85mm (95% CI, 0.41 to 3.29 mm), respectively, which were significantly less than the predetermined 5mm threshold (p<0.001 and p<0.01, respectively). Removal torque between fully cemented stems was 45.22 Nm (95% CI, 21.86 to 68.57 Nm), versus 9.26 Nm (95% CI, 2.59 to 15.93 Nm) for partially cemented samples (p=0.021). Every fully cemented humerus fractured during implant removal versus only one in the reduced cementation group. The mean donor age in our study was 76 years (range, 65 to 80 years). Only one matched pair of humeri belonged to a female donor with comorbid osteoporosis. The fractured humerus in the partially cemented group belonged to that donor. ConclusionPartially and fully cemented humeral prostheses had subsidence that was significantly less than 5 mm. Partially cemented stems required less removal torque for de-bonding of the component from the cement mantle. In all cases, removal of fully cemented stems resulted in humeral fracture. Reduced cementation of humeral prostheses may provide both sufficient biomechanical stability and ease of future component removal.

Mechanical property—processing relations for SiC foams synthesized via polymer particle templating of polycarbosilane

AbstractSilicon carbide foams with an average pore diameter of 650 nm and an inter‐pore ligament thickness of 150 nm have been synthesized using spherical polymethylmethacrylate (PMMA) particle templating of a β‐SiC nanoparticle‐loaded polycarbosilane (PCS) preceramic polymer and the effect of crystallization temperature upon their microstructure and mechanical properties investigated. Differential scanning calorimetry and thermogravimetric analysis were used to investigate both the kinetics of PMMA decomposition and the influence of β‐SiC nanoparticles upon the mechanisms of PCS cure, pyrolysis, and partial crystallization. As the crystallization temperature was systematically increased, the inter‐pore ligament structure coarsened and nanopores developed within the ligaments between the β‐SiC nanoparticles. The foam's Young's modulus and compressive strength at first increased with crystallization temperature, reaching a maximum after processing at 1300˚C. However, further increases in temperature resulted in a rapid fall in both foam modulus and compressive strength. To gain insight into the fundamental processes responsible for the overall (macroscale) mechanical properties, models for open/closed cell foams were inverted and used in conjunction with the measured foam density, Young's modulus, and compressive strength to estimate the mechanical properties of the inter‐pore ligaments. This procedure indicated that changes to the ligament properties were responsible for the observed dependence of the foam mechanical properties upon crystallization temperature.

Scattering enhancement of partially buried sphere at the water-sand interfaces due to reflected subsonic Rayleigh waves

In view of the development needs of maritime security, the detecting of buried targets over long distances at low frequencies needs to be solved urgently. Through well designed experiments at low frequency (ka = 5–10), this paper presents a study on the scattering echoes from polymethylmethacrylate (PMMA) spheres in partially buried cases (50%, 75% and 100% buried), and the propagation characteristics of subsonic Rayleigh surface waves on the surface of PMMA spheres at the water-sand interface can be clearly observed. It is shown that the fine sand medium with larger impedance brings about smaller circumferential phase and group velocities of subsonic Rayleigh waves on the surface of the PMMA sphere; the resonance peak caused by subsonic Rayleigh waves is shifted toward the low frequency with the deepening of the burial depth, and the offset can be predicted by the circumferential phase velocity of the subsonic Rayleigh wave in different media and burial depth of PMMA sphere, and the experimental and finite element simulation results validate the shift of the Rayleigh resonance peak. The research results of this paper can provide certain reference value for the detection of low frequency buried targets.

Synthesis of PMMA Microspheres with Tunable Diameters: Evaluation as a Template in the Synthesis of Tin Oxide Coatings.

The synthesis of polymethyl methacrylate (PMMA) spheres with different sizes has been a challenge. PMMA has promise for future applications, e.g., as a template for preparing porous oxide coatings by thermal decomposition. Different amounts of SDS as a surfactant are used as an alternative to control PMMA microsphere size through the formation of micelles. The objectives of the study were twofold: firstly, to determine the mathematical relationship between SDS concentration and PMMA sphere diameter, and secondly, to assess the efficacy of PMMA spheres as templates for SnO2 coating synthesis and their impact on porosity. The study used FTIR, TGA, and SEM techniques to analyze the PMMA samples, and SEM and TEM techniques were used for SnO2 coatings. The results showed that PMMA sphere diameter could be adjusted by varying the SDS concentration, with sizes ranging from 120 to 360 nm. The mathematical relationship between PMMA sphere diameter and SDS concentration was determined with a y = axb type equation. The porosity of SnO2 coatings was found to be dependent on the PMMA sphere diameter used as a template. The research concludes that PMMA can be used as a template to produce oxide coatings, such as SnO2, with tunable porosities.

Combustion of spherical PMMA samples in still air simulated using a skeletal chemical kinetic mechanism

The combustion of spherical samples of polymethyl methacrylate (PMMA) under natural convection was studied experimentally and by CFD simulation. Species mole fraction and temperature profiles in the flame were measured by microprobe mass spectrometry and microthermocouples. Gas flow around a solid sphere was modeled using the full Navier–Stokes equations for a multicomponent mixture, with a skeletal chemical kinetic mechanism taking into account heat transfer, convection, and radiation. A kinetic model has been developed that includes the surface pyrolysis of PMMA and a skeletal kinetic mechanism for the gas-phase combustion of its monomer, methyl methacrylate (MMA). Satisfactory agreement between the experimental data and the results of 3D modeling for the chemical and thermal structure of the flame has proven the efficiency of the proposed chemical kinetic model. An analysis of the obtained data has shown that in the diffusion combustion of the spherical samples, the region of the stoichiometric composition of the gas mixture does not coincide with the region of maximum temperature. It has been found that under the conditions studied, gas-phase MMA decomposition proceeds mainly through radical reactions and unimolecular decomposition plays only a minor role.

Backscattering enhancements by partially exposed spheres due to reflected subsonic Rayleigh waves at air-water interfaces.

Air-water interfaces can enable distinct target scattering mechanisms different from the mechanism under free field conditions. In this study, backscattering experiments are performed by lowering an acrylic or polymethylmethacrylate sphere through the air-water interface into the water and insonifying the sphere from below at grazing incidence. Pronounced backscattering enhancements associated with the subsonic Rayleigh wave propagation mechanism are observed before the specular reflection point of the sphere reaches the water. The results indicate that, for a partially exposed sphere, subsonic Rayleigh waves can pass through the air-water interface and circumnavigate the sphere multiple times. The phase velocities of Rayleigh waves are different when propagating above and below the air-water interface. Moreover, subsonic Rayleigh waves are partially reflected when passing through the air-water interface, generating wavefronts that propagate in the reverse direction.

OBTAINING SEMICONDUCTOR CdS, CdSe AND CdSe/ZnS CORE/SHELL NANOPARTICLES AND THEIR COMPOSITES WITH POLYMERS

In this work, high-performance CdS, CdSe and CdSe/ZnS nanocrystals with good luminescence were colloidally synthesized at high temperature and incorporated into micrometer-sized polymethylmethacrylate (PMMA) spheres formed by suspension polymerization reaction. CdS, CdSe and CdSe/ZnS quantum dots obtained by the colloid method were stabilized with oleic acid and their optical properties were studied. It was observed that the intensity peaks of quantum dots did not change after modification to PMMA polymer.

OBTAINING SEMICONDUCTOR CdS, CdSe AND CdSe/ZnS CORE/SHELL NANOPARTICLES AND THEIR COMPOSITES WITH POLYMERS

In this work, high-performance CdS, CdSe and CdSe/ZnS nanocrystals with good luminescence were colloidally synthesized at high temperature and incorporated into micrometer-sized polymethylmethacrylate (PMMA) spheres formed by suspension polymerization reaction. CdS, CdSe and CdSe/ZnS quantum dots obtained by the colloid method were stabilized with oleic acid and their optical properties were studied. It was observed that the intensity peaks of quantum dots did not change after modification to PMMA polymer.

Countercurrent Flame Propagation and Quenching Behaviour in a Packed Bed of Spherical PMMA Beads in an Upward Flow of Pure Oxygen

ABSTRACT Countercurrent flame propagation and quenching behavior in a packed bed of spherical polymethyl methacrylate (PMMA) beads in an upward flow of pure oxygen was experimentally studied. Monosized PMMA beads of 2, 5, 8 or 10 mm in diameter (d) were packed in a vertical quartz tube of 35 mm ID to form a bed of 180 mm in height. In a typical experimental run, upon ignition from the top, a blue flame formed and propagated downwards. For d = 10, 8, or 5 mm, there existed a minimum oxygen flow rate (q) to sustain a quasi-steady state flame propagation, and the minimum q increased as d decreased from 10 to 5 mm. However, for d = 2 mm, it was not possible for the flame to propagate downwards irrespective of the q value. The apparent pyrolysis rate (m py) of PMMA was estimated by monitoring the bed mass loss rate, from which the nominal equivalence ratio upon flame quenching was also estimated. The equivalence ratio was found to be less than unity upon flame quenching, suggesting insufficient pyrolysis gases to sustain the combustion. The heat transfer between flame and PMMA bead was analyzed theoretically, and it was revealed that the minimum m py to sustain the quasi-steady state flame propagation inversely correlates with the PMMA particle size, and therefore a higher oxygen flow rate is required to sustain the flame propagation in a packed bed of smaller PMMA particles.

Tuning the optimal diffusion-weighted MRI parameters on a 0.35-T MR-Linac for clinical implementation: A phantom study.

This study aims to assess the quality of a new diffusion-weighted imaging (DWI) sequence implemented on an MR-Linac MRIdian system, evaluating and optimizing the acquisition parameters to explore the possibility of clinically implementing a DWI acquisition protocol in a 0.35-T MR-Linac. All the performed analyses have been carried out on two types of phantoms: a homogeneous 24-cm diameter polymethylmethacrylate (PMMA) sphere (SP) and a homemade phantom (HMP) constating in a PMMA cylinder filled with distilled water with empty sockets into which five cylindrical vials filled with five different concentrations of methylcellulose water solutions have been inserted. SP was used to evaluate the dependence of diffusion gradient inhomogeneity artifacts on gantry position. Four diffusion sequences with b-values of 500 s/mm2 and 3 averages have been acquired: three with diffusion gradients in the three main directions (phase direction, read direction, slice direction) and one with the diffusion gradients switched off. The dependence of diffusion image uniformity and SNR on the number of averages in the MR sequences was also investigated to determine the optimal number of averages. Finally, the ADC values of HMP have been computed and then compared between images acquired in the scanners at 0.35 and 1.5 T. In order to acquire high-quality artifact-free DWI images, the "slice" gradient direction has been identified to be the optimal one and 0° to be the best gradient angle. Both the SNR ratio and the uniformity increase with the number of averages. A threshold value of 80 for SNR and 85% for uniformity was adopted to choose the best number of averages. By making a compromise between time and quality and limiting the number of b-values, it is possible to reduce the acquisition time to 78 s. The Passing-Bablok test showed that the two methods, with 0.35 and 1.5 T scanners, led to similar results. The quality of the DWI has been accurately evaluated in relation to different sequence parameters, and optimal parameters have been identified to select a clinical protocol for the acquisition of ADC maps sustainable in the workflow of a hybrid radiotherapy system with a 0.35-T MRI scanner.

Ignition of thermally-thick blunt body PMMA samples using a heated wire

Ignition limits and ignition delay times of thermally-thick polymethyl methacrylate (PMMA) spheres (4-cm diameter) and cylinders (5.08-cm diameter) are investigated by placing an electrically-heated wire coil beneath the sample in a slow forced flow. The wire serves as both a heater for the solid sample and a gas-phase hot spot to ignite the oxidizer-fuel vapor mixture. In the experiments, the wire's electrical current and power-on time, its distance from the sample surface, the forced flow velocity, oxygen percentage, and pressure are systematically varied. Ignition limits as a function of the oxygen percentage, pressure, and igniter current are determined. Two ignition delay times are determined: igniter-assisted ignition and self-sustained ignition. These critical times are also functions of the degree of heat-up of the sample interior. Solid temperature profiles are measured using embedded thermocouples to determine the sub-surface temperature gradients at the moment of ignition. The heat transfer modes from the igniter to the solid sample are numerically investigated during the pre-pyrolysis heat-up period. At the forward stagnation-point region where ignition occurs, radiation is greater than convection and accounts for approximately 60% of the total heat input. This is consistent with the experimental findings on ignition delay times and heat flux measurements.

Biomarker responses in zebrafish (Danio rerio) following long-term exposure to microplastic-associated chlorpyrifos and benzo(k)fluoranthene.

Continuously increasing plastic production causes a constant accumulation of microplastic particles (MPs) in the aquatic environment, especially in industrialized and urbanized areas with elevated wastewater discharges. This coincides with the release of persistent organic pollutants (polycyclic aromatic hydrocarbons (PAHs), pesticides) entering limnic ecosystems. Although the assessment of potential effects of environmental pollutants sorbed to MPs under chronic exposure scenarios seems vital, data on potential hazards and risk by combined exposure to pollutants and microplastics for aquatic vertebrates is still limited. Therefore, zebrafish (Danio rerio) were exposed over 21 days to the organophosphate insecticide chlorpyrifos (CPF; 10 and 100ng/L) and the PAH benzo(k)fluoranthene (BkF; 0.78 and 50µg/L) either dissolved directly in water or sorbed to different MPs (irregular polystyrene, spherical polymethyl methacrylate; ≤ 100µm), where CPF was sorbed to polystyrene MPs and BkF was sorbed to polymethyl methacrylate MPs. Contaminant sorption to MPs and leaching were documented using GC-EI-MS; potential accumulation was studied in cryosections of the gastrointestinal tract. Enzymatic biomarkers and biotransformation were measured in liver and brain. Overall, exposure to non-contaminated MPs did not induce any adverse effects. Results of fluorescence tracking, CYP1A modulation by BkF as well as changes in acetylcholinesterase activity (AChE) by CPF were less pronounced when contaminants were sorbed to MPs, indicating reduced bioavailability of pollutants. Overall, following exposure to waterborne BkF, only minor amounts of parent BkF and biotransformation products were detected in zebrafish liver. Even high loads of MPs and sorbed contaminants did not induce adverse effects in zebrafish; thus, the potential threat of MPs as vectors for contaminant transfer in limnic ecosystems can be considered limited.

Synthesis of Honeycomb-Shaped LiNi0.5Mn0.5O2 Using a Sol-Gel Method with Polymethylmethacrylate (PMMA) and Organic Surfactant

Layered-structural LiNi0.5Mn0.5O2 has high discharge capacity, abundant availability, enhanced chemical stability, convenient environmental benignancy, and low cost. However, LiNi0.5Mn0.5O2 suffers from poor intrinsic rate capability due to its poor ionic conductivity (2.54 × 10-7 S/cm) and poor cycle stability owing to the volume change of the cathode materials during cycling. To address this issue, honeycomb-shaped LiNi0.5Mn0.5O2 was developed for lithium-ion batteries using a sol-gel method with spherical polymethylmethacrylate (PMMA) particles. PMMA particles provide spherical voids in LiNi0.5Mn0.5O2 cathode materials due to their relatively low decomposition temperature (&lt; 350 °C). Honeycomb-shaped LiNi0.5Mn0.5O2 has a higher surface area (2.63 m2/g) than the LiNi0.5Mn0.5O2 (2.00 m2/g) produced by conventional sol-gel method. The initial discharge capacities of conventional nano LiNi0.5Mn0.5O2 and honeycomb-shaped LiNi0.5Mn0.5O2 are 151.9 mAh g-1 and 200.4 mAh g-1, respectively at 0.1 C. After 50 cycles at 1 C, honeycomb-shaped LiNi0.5Mn0.5O2 has a larger capacity retention than conventional nano LiNi0.5Mn0.5O2, measuring 67.9% and 58.8%, respectively. The superior electrochemical performance of honeycomb-shaped LiNi0.5Mn0.5O2 increases the effective surface area for Li-ion diffusion, leading to better rate capability, and buffers the volume change during Li+ion insertion/extraction, improving the cycling stability.

A homogenization model for the rheology and local field statistics of suspensions of particles in yield stress fluids

We investigate the rheological behavior of athermal particle suspensions using experiments and theory. A generalized version of the homogenization estimates of Ponte Castañeda and Willis [J. Mech. Phys. Solids, 43(12), 1919–1951 (1995)] is presented for the effective viscosity of athermal suspensions accounting for additional microstructural features (e.g., polydispersity) via an empirical parameter, λ. For the case of identically sized spheres dispersed with statistical isotropy in a Newtonian fluid, the parameter λ is estimated from the results of Batchelor and Green [J. Fluid Mech. 56(2), 375–400 (1972)] for the Huggins coefficient. Predictions for the macroscopic viscosity are found to be in good agreement with measurements for monodisperse polymethyl methacrylate (PMMA) spheres in glycerol, as well as for the empirical Krieger–Dougherty equation for the shear viscosity. The proposed estimates have the added benefit that they can also be used to get information on the statistics of the stress and strain-rate fields in the fluid and particle phases. In addition, results for the effective shear viscosity are used in combination with the linear comparison method of Ponte Castañeda [J. Mech. Phys. Solids 39(1), 45–71 (1991)] to generate the corresponding estimates for the effective macroscopic behavior and field statistics of particle suspensions in (viscoplastic) yield stress fluids. Good agreement is also found between the theoretical estimates and experimental results for the effective yield and flow stress of suspensions with monodisperse PMMA spheres in Carbopol. Finally, it is argued that the results for the phase averages and fluctuations of the stress and strain-rate fields can be used to provide a physical interpretation for the parameter λ in terms of the polydispersity of the suspension and its implications for the percolation threshold.

Thermal transport in silver-coated polymer sphere composites by the bidirectional 3ω method

The bidirectional 3ω method is an electrothermal technique that is commonly used to obtain the thermal conductivity of materials such as liquids, biological samples, and pastes. In this work, an epoxy-based adhesive was filled with monodisperse 10 μm polymethyl methacrylate spheres coated with silver thin films (AgPS), such that a metallic network that dominated the thermal transport was formed through the composite. The bidirectional 3ω method was used to obtain the thermal conductivity of the conductive adhesive at different volume fractions of AgPS. For 50 vol.% AgPS, corresponding to 3.4 vol.% silver, the thermal conductivity was 2.03±0.21 W m−1 K−1. The results show that the thermal conductivity is strongly correlated with the AgPS volume fraction, while maintaining a volume fraction of silver far below the commercial silver paste, which has typical filler fractions of 40 vol.% silver. The results of this work were compared to thermal measurements of the same material by other techniques, and advantages and disadvantages of the methods were finally discussed.

Atomically Dispersed Pt on Three-Dimensional Ordered Macroporous SnO2 for Highly Sensitive and Highly Selective Detection of Triethylamine at a Low Working Temperature.

Triethylamine (TEA) is a widely used volatile organic chemical, which is harmful and can cause headache, dizziness, and respiratory discomfort. Developing an efficient sensor to detect trace amounts of TEA is significant for industrial and healthcare monitoring. In this work, SnO2 with a three-dimensional ordered macroporous structure (3DOM) was prepared through a polymethylmethacrylate sphere template route. The TEA sensing performance of the 3DOM SnO2 was enhanced through Pt loading. Aberration-corrected high-angle annular dark-field scanning transmission electron microscopy images and X-ray absorption fine-structure analysis indicate that Pt on the 3DOM 0.20% Pt/SnO2 surface mainly exists in the state of atomic dispersion, which results in more active sites, higher Hall mobility and active oxygen contents, and lower response energy barriers. The 0.20% Pt/SnO2 sensor has a low operating temperature of 80 °C and a low limit of detection (0.32 ppb). Because of the uniform adsorption of TEA on the atomically dispersed Pt, the 3DOM Pt/SnO2 sensor exhibits high selectivity.

Microwave and terahertz properties of porous Ba4(Sm,Nd,Bi)28/3Ti18O54 ceramics obtained by sacrificial template method

AbstractMicrowave and terahertz communications are increasingly significant, however, the lack of material information in terahertz band limits their development. Moreover, few lightweight materials with a high relative dielectric constant () are found suited for satellite communication and wearable devices. In this study, we developed lightweight porous Ba4[(Sm0.1Nd0.9)0.9Bi0.1]28/3Ti18O54 (BSNBT) ceramics exhibiting a total porosity ranging from 6.3% to 26.5% (bulk density ranging from 5.47 to 4.29 g/cm3) and relatively high ranging from 85.6 to 56.8, which were obtained by sacrificial template method using polymethyl methacrylate spheres (PMMAs) of varying average particle sizes, from 9 to 34 μm, as sacrificial materials. A high refractive index ranging between 7.5 and 8.9 and a low absorption coefficient of approximately 17 cm−1 at 0.3 THz were obtained for the porous ceramics with different total porosities derived from PMMAs with average particle sizes of 9 and 19 μm. Furthermore, effective medium and Mie scattering theories were applied to understand the effects of porous structure on the dielectric properties in microwave and terahertz frequency ranges, respectively, owing to the different wavelengths in the BSNBT matrix. The results of this study suggest that introducing a porous structure can effectively exploit lightweight microwave dielectric ceramic materials and provide valuable information on their terahertz response mechanism.

Roughly Spherical: Tailored PMMA-SiO2 Composite Supraparticles with Optimized Powder Flowability for Additive Manufacturing.

Particulate materials with well-engineered properties are of key importance for many aspects in our daily life. Polymer powders with high flowability, for example, play a crucial role in the emerging field of powder-based additive manufacturing processes. However, the polymer- and composite material selection for these technologies is still limited. Here, we demonstrate the design of spherical polymethyl methacrylate (PMMA) and PMMA-SiO2 composite supraparticle powders with excellent powder flowability and tailored composition for powder-based additive manufacturing. Our process assembles these powders from the bottom up and affords a precise control over surface roughness and internal morphology via the choice of colloidal primary particles. We establish process-structure-property relationships connecting external spray-drying parameters and primary particle sizes with the resulting supraparticle roughness and, subsequently, with the macroscopic powder flowability and powder bed density. In a second step, we demonstrate the control of composition and internal morphology of PMMA-SiO2 composite supraparticles based on different mass mixings and diameter ratios of the two primary particle dispersions. Finally, we successfully apply the prepared supraparticle powders in powder bed additive manufacturing. The optimized flowability of the composite powders allows the production of two-layered square specimens with fusion between the individual layers and a uniform and tunable distribution of nanoscale SiO2 additives without requiring the addition of any flowing aids.

Anisotropic polymer-mesoporous silica hybrid particles with tailorable morphology

Anisotropic particles have recently attracted tremendous attention because of its unique structure and properties. However, it is still a great challenge to control the anisotropic growth to precisely control the particle morphology. In this paper, an anisotropic polymer -mesoporous silica hybrid particle (PMS) was fabricated by regional growth of periodic mesoporous organosilica (PMO) on polymethyl methacrylate (PMMA) sphere surface. The connection between PMO and PMMA is reinforced by electrostatic interaction and molecular crosslink. The asymmetric regional distribution of silicon and carbon is verified by the elemental mapping. The morphology of PMS is highly tailorable through the control of reaction time, silane concentration and particle diameters. PMO thickness and its coverage on PMMA surface are two main characteristics that remarkably shape the PMS architecture. This work provides a versatile route to prepare inorganic-organic hybrid particles with asymmetric composition and diverse geometry.