Polymer Core Research Articles

Adhesion Behavior of Ti\u2013PMMA\u2013Ti Sandwiches for Biomedical Applications

The “stress-shielding” problem, common with metallic implants, may be solved by using biocompatible sandwiches with a polymeric core between two metallic skin sheets. To achieve such sandwiches, a process route has been developed, beginning with the grafting of poly-(methyl-methacrylate) (PMMA) on titanium (Ti) sheets via the “grafting from” technique. Grafting resulted in variable thicknesses of PMMA on the Ti sheets. Hot-pressing was used to prepare semi-finished Ti–PMMA–Ti sandwiches. The adhesion was achieved by the interpenetration between PMMA sheet and the grafted PMMA chains. Investigation was carried out to understand the influence of the grafted PMMA thickness on the adhesion strength. Similar adhesion strengths were found for the sandwiches despite variable grafted PMMA thicknesses, indicating a successful grafting of PMMA on large-scale Ti sheets. The adhesion followed the autohesion theory, where a time-dependent increase in adhesion strength was found for the sandwiches.

Development of polystyrene/polyaniline/ceria (PS/PANI/CeO2) multi-component abrasives for photochemical mechanical polishing/planarization applications

Tri-layer nanostructured polystyrene/polyaniline/ceria (PS/PANI/CeO2) multi-component composites were developed as functionalized particle abrasives for improved photochemical mechanical polishing/planarization (PCMP) applications. The physicochemical characteristics of the PS/PANI/CeO2 and PS/CeO2 samples were examined by X-ray diffraction, transmission electron microscopy, scanning electron microscopy, Flourier-transform infrared spectroscopy, UV–visible spectrophotometer, photoluminescence spectroscopy, and thermogravimetric analysis. Ultra-smooth and defect-free surfaces with ultra-low roughness (0.12 nm Ra, 0.16 nm RMS) were achieved after PCMP with polymer/CeO2 hybrid abrasives. It might be attributed to the enlarged contact area and the decreased indention depth between the particle and the surface, possibly originating from the elastic polymer cores. The synergy of the PANI conductive polymer and the CeO2 particle photocatalyst contributed to improving the separation efficiency of photo-generated carriers, thereby enhancing the photochemical oxidation activity. As expected, the tri-layer PS/PANI/CeO2 abrasives achieved a ca. 69% increment of material removal rate compared to the PS/CeO2. The interfacial contact model and material modification/removal mechanism of the PS/PANI/CeO2 multi-component tri-layer abrasives during PCMP processes were also discussed. The aim of this work is expected to provide guidance for the design and promising applications of novel polymer/CeO2 composite abrasives in advanced CMP, PCMP, electrochemical mechanical polishing (ECMP), and photoelectrochemically combined mechanical polishing (PECMP).

A polymer‑calcium phosphate nanocapsule for RNAi-induced oxidative stress and cascaded chemotherapy

As most of intracellular reactive oxygen species (ROS) is produced in the mitochondria, mitochondrial modulation of cancer cell is a promising strategy for maximizing the in situ-activable combination therapy of oxidative catastrophe and cascaded chemotherapy. Herein, a serum-stable polymer‑calcium phosphate (CaP) hybrid nanocapsule carrying siRNA against ADP-ribosylation factor 6 (Arf6) overexpressed in cancer cells and parent drug camptothecin (CPT), designated as PTkCPT/siRNA, was developed for the RNAi-induced oxidative catastrophe and cascaded chemotherapy. A copolymer of mPEG-P(Asp-co-TkCPT), covalently tethered with chemotherapeutic CPT via a ROS-labile dithioketal (Tk) linker, was synthesized and self-assembled into a PTkCPT micelle as a nanotemplate for the CaP mineralization. The as-prepared PTkCPT/siRNA nanoparticle showed a core-shell-distinct nanocapsule which was consisted of a spherical polymeric core enclosed within a CaP shell capable of releasing siRNA in response to lysosomal acidity. Blocking Arf6 signal pathway of cancer cells led to their mitochondrial aggregation and subsequently induced a burst of ROS for oxidative catastrophe, which further triggered the cascaded CPT chemotherapy via the breakage of ROS-labile dithioketal linker. This strategy of RNAi-induced oxidative catastrophe and cascaded chemotherapy resulted in a significant combination effect on cancer cell killing and tumor growth inhibition in mice with low side effects, and provided a promising paradigm for precise cancer therapy.

Insight into multilayered alginate/chitosan microparticles for oral administration of large cranberry fruit extract

• Up to 7 layers (CHIT and ALG mv ) shell were built on the CFE-loaded ALG-based cores. • The shell was a non-lamellar, interpenetrating network of oppositely charged polysaccharides. • The mechanical resistance depends on the type of ALG used as the core material and the shell structure. • The three-layered microcapsules showed the best performance in the in vitro release study. • The applicability of the studied particles could be controlled by their core and shell structure. We present a series of multilayered alginate/chitosan microparticles fabricated via combining ionic gelation with the layer-by-layer (LbL) approach to improve oral administration of large cranberry fruit extract (CFE). Sodium alginate of low (ALG lv ) or medium (ALG mv ) viscosity was used as a core polymer, and chitosan (CHIT) and ALG mv layers were alternately assembled to form up to seven layers’ coating. Microparticles size ranged between 640 and 1120 μm, and their morphology, moisture content, and structural integrity were affected mainly by the outermost layer’s composition. Both the microgel core and shell composition of these microparticles influenced the mechanical properties determined by the parallel plates compression test. Microparticles exhibited good CFE entrapment efficiency (E.E. > 55%) and favorable release profiles in the simulated gastro-intestine environment, well described by the hybrid model of the release kinetics. Our results evidence that polysaccharide-inspired microparticles are good platforms for enhancing the oral bioavailability of poorly water-soluble therapeutic agents.

Reaction-diffusion model to quantify and visualize mass transfer and deactivation within core-shell polymeric microreactors

HypothesisThe performance of a polymeric core–shell microreactor depends critically on (i) mass transfer, (ii) catalyzed chemical reaction, and (iii) deactivation within the nonuniform core–shell microstructure environment. As such, these three basic working principles control the active catalytic phase density in the reactor. TheoryWe present a high-fidelity, image-based nonequilibrium computational model to quantify and visualize the mass transport as well as the deactivation process of a core–shell polymeric microreactor. In stark contrast with other published works, our microstructure-based computer simulation can provide a single-particle visualization with a micrometer spatial accuracy. FindingsWe show how the interplay of kinetics and thermodynamics controls the product-induced deactivation process. The model predicts and visualizes the non-trivial, spatially resolved active catalyst phase patterns within a core–shell system. Moreover, we also show how the microstructure influences the formation of foulant within a core–shell structure; that is, begins from the core and grows radially onto the shell section. Our results suggest that the deactivation process is highly governed by the porosity/microstructure of the microreactor as well as the affinity of the products towards the solid phase of the reactor.

Synthesis of Fe3O4@Zn-BDC nanocomposite for the removal of MB from aqueous solution

Coordination polymers (CPs) are a significant platform for dye adsorption. Designing Fe3O4@CP nanocomposites as easy-recoverable adsorbents could facilitate their recycling. In this research, a core-shell Fe3O4@CP nanocomposite was prepared for methylene blue (MB) adsorption and removal from aqueous solutions. The obtained nanocomposite consists of Fe3O4 core and coordination polymer shell constructed from Zn2+ and benzene-1,4-dicarboxylic acid (H2-BDC) which formed with layer-by-layer assembly. The formation of the core-shell nanostructure was approved with various physicochemical techniques. The microscopy results confirmed a core-shell nanostructure for Fe3O4@CP nanocomposite that shell thickness is about 5–7 nm. The adsorption experiments indicated that Fe3O4@CP nanocomposite not only adsorbed more than 86% of MB only after 2 min, it significantly could be separated magnetically and reused without evident loss of adsorption efficiency after four cycles.

Failure analysis of metal-polymer-metal sandwich panels with wire mesh interlayers: Finite element modeling and experimental validation

Vacuum hot pressing of a thermoplastic core and metal skin sheets resistance welded to wire meshes is used to fabricate high interface strength metal-polymer-metal sandwich panels. The wire mesh strongly bonds with polymer core from material interlocking and it bonds with metal skin from welding. A finite element (FE) model is developed for characterizing the deformation behavior and failure of fabricated sandwich panels. While, a continuum ductile damage model is used to characterize failure of layers in stretching, a cohesive zone model is used to characterize interface failure. The FE model is validated using tensile tests, peel tests, double lap shear tests, and V-bending experiments. Good match is seen between simulations and experiments. In V-bending, spring back as well as debonding is correctly predicted. Sandwich panels fabricated in this work form an attractive alternative to adhesively bonded panels. The developed finite element model can be used for forming analysis of developed sandwich panels and for optimizing the panel architecture.

Span 80/TPGS modified lipid-coated chitosan nanocomplexes of acyclovir as a topical delivery system for viral skin infections

Acyclovir (ACR) is considered the gold standard drug for the treatment of skin viral infections caused by the herpes simplex or varicella-zoster virus. However, topical therapy with ACR is hindered by its poor skin penetrability, thus necessitating high doses and frequent administrations. This study was proposed to formulate a modified lipid-coated chitosan nanocomplexes (LCNCs) of acyclovir (ACR), containing span 80 and TPGS, to boost the dermal delivery of ACR and improve the therapeutic outcomes. LCNCs were formulated through a self-assembly method, and the statistical analysis and the optimization were performed via a general 23 factorial design. Three formulation variables were selected; namely, the amount of chitosan (A), the amount of glyceryl monooleate (GMO) (B), and span 80: D-α-tocopheryl polyethylene glycol succinate (Vitamin ETPGSorTPGS) ratio (C). Four measured attributes were determined; viz., the particle size (PS) in nm, the polydispersity index (PDI), the zeta potential (ZP) in mV, and the entrapment efficiency percentages (EE%). The optimal formulation (LCNCs 8), formulated with 600 mg chitosan, 120 mg GMO, and 3:1 span 80: TPGS ratio, possessed PS of 177.50 ± 1.41 nm, PDI value of 0.28 ± 0.02, ZP of −10.70 ± 0.85 mV, and EE% of 77.20 ± 2.40 %, and was able to sustain ACR release over 24 h. Transmission electron microscopy displayed LCNCs architecture as a polymeric core of chitosan with a lipid coat of GMO, and the solid-state characterization results confirmed the dispersion of ACR in LCNCs. The ex vivo permeation study and the in vivo dermatokinetics profile verified the boosted accumulation of ACR in the skin via LCNCs, while the confocal laser scanning microscopy revealed the heightened penetrability of LCNCs. The topical application of LCNCs demonstrated a safe profile via the modified Draize test and histopathological examinations. Inclusively, ACR-loaded LCNCs could be a promising topical formulation with an advanced dermal delivery status for the treatment of skin viral infections.

Magnetic cluster-encapsulated polymer dimers with controlled surface property

This work reports the fabrication of magnetic polymer dimers with controlled surface anisotropy. The fabrication process involves the preparation of magnetite (Fe3O4) magnetic clusters with strong magnetism, followed by their surface modification, dispersion polymerization while using them as seeds, multilayer shell formation via layer-by-layer deposition, and polymer core swelling. The interplay between the swelling and multilayer shells generates pressure inside the multilayer-deposited, magnetic polystyrene (PS) spheres, forming structurally anisotropic dimers with single PS protrusions anchored on the multilayer surfaces within minutes. The use of titania precursor and different swelling agents, along with the change in the composition of the multilayer shell, enables the introduction of different surface anisotropies, such as the surface-charge anisotropy, anisotropic hydrophilicity/hydrophobicity, and material composition anisotropy, to the dimers. The strong magnetic response of the dimers, attributed to the magnetic cluster seeds, in combination with the surface-charge and material composition anisotropies allows a rapid magnetic recovery and an excellent reusability, enabling their application to 20-cycled reduction of 4-nitrophenol (4-NP) and methylene blue (MB) without loss of catalytic activity. Furthermore, the anisotropic hydrophilicity/hydrophobicity makes the dimers potentially useful as solid surfactant to stabilize immiscible oil–water mixture.

The effect of formulation morphology on stimuli-triggered co-delivery of chemotherapeutic and MRI contrast agents

Most conventional chemotherapeutics have narrow therapeutic windows, and thus their delivery remains challenging and often raises safety and efficacy concerns. Theranostic platforms, with simultaneous encapsulation of therapeutic and diagnostic agents, have been proposed as next-generation formulations which can overcome this issue. In this work, we used electrohydrodynamic approaches to fabricate core@shell formulations comprising a pH responsive Eudragit L100 shell embedded with superparamagnetic iron oxide nanoparticles (SPIONs), and a thermo-responsive poly(N-isopropylacrylamide) (PNIPAM)/ethyl cellulose core loaded with the model drug carmofur. By varying the weight ratio of core polymer to shell polymer, the morphology of PNIPAM/ethyl cellulose@Eudragit L100 microparticles could be changed from concave to spherical. Smooth cylindrical fibres could also be generated. All the formulations exist as amorphous solid dispersions of drug-in-polymer, with distinct core@shell architectures. The fibres have clear thermo-responsive drug release profiles, while no thermo-responsive properties can be seen with the particles. All the formulations can protect SPIONs from degradation in gastric fluids (pH ∼ 1.5), and around the physiological pH range the materials offer effective and pH-responsive relaxivity. The r2 values also display clear linear relationships with drug release data, suggesting the potential of using MRI signals to track drug release in vivo. Mathematical equations were established to track drug release in vitro, with very similar experimental and predicted release profiles obtained.

Design of Over-1000 nm Near-Infrared Fluorescent Polymeric Micellar Nanoparticles by Matching the Solubility Parameter of the Core Polymer and Dye.

Polymeric micellar nanoparticles (PNPs) encapsulating over-thousand-nanometer (OTN) near-infrared (NIR) fluorescent dye molecules in block polymers having hydrophobic and hydrophilic chains are promising agents for the dynamic imaging of deep tissue. To achieve OTN-NIR fluorescent PNPs (OTN-PNPs) having high brightness, it is crucial to increase the affinity between the core polymer and dye molecules by matching their polarities; thus, criteria and methods to evaluate the affinity are required. In this study, we used the Hansen solubility parameter (HSP), including the polarity term, to evaluate the affinity between the two substances. HSP values of the OTN-NIR fluorescent dye IR-1061 and four core polymers, poly(lactic-co-glycolic acid) (PLGA), poly(lactic acid) (PLA), poly(ε-caprolactone) (PCL), and polystyrene (PSt), were calculated using the Hansen solubility sphere method and molecular group contribution method, respectively. The relative energy density between IR-1061 and each core polymer calculated using their HSP values revealed that the affinities of PLGA and PLA for IR-1061 are higher than those of PCL and PSt. Therefore, OTN-PNPs composed of PLGA, PLA, and PCL core polymers were prepared and compared. The OTN-PNPs having PLGA and PLA cores could be loaded with larger amounts of IR-1061, had higher photoluminescence intensities, and showed higher stability in phosphate buffered saline than those having PCL cores. Moreover, the OTN-PNPs having PLGA or PLA cores were used for the dynamic imaging of live mice. Thus, matching the solubility parameters of the core polymer and dye molecule is a useful approach for designing high-performance OTN-NIR fluorescent probes.

Free vibration analysis of imperfect functionally graded sandwich plates: analytical and experimental investigation

Purpose: This paper develops a new analytical solution to conduct the free vibration analysis of porous functionally graded (FG) sandwich plates based on classical plate theory (CPT). The sandwich plate made of the FGM core consists of one porous metal that had not previously been taken into account in vibration analysis and two homogenous skins. Design/methodology/approach: The analytical formulations were generated based on the classical plate theory (CPT). According to the power law, the material properties of FG plates are expected to vary along the thickness direction of the constituents. Findings: The results show that the porosity parameter and the power gradient parameter significantly influence vibration characteristics. It is found that there is an acceptable error between the analytical and numerical solutions with a maximum discrepancy of 0.576 % at a slenderness ratio (a/h =100), while the maximum error percentage between the analytical and experimental results was found not exceeding 15%. Research limitations/implications: The accuracy of analytical solutions is verified by the adaptive finite elements method (FEM) with commercial ANSYS 2020 R2 software. Practical implications: Free vibration experiments on 3D-printed FGM plates bonded with two thin solid face sheets at the top and bottom surfaces were conducted. Originality/value: The novel sandwich plate consists of one porous polymer core and two homogenous skins which can be widely applied in various fields of aircraft structures, biomedical engineering, and defense technology. This paper presents an analytical and experimental study to investigate the free vibration problem of a functionally graded simply supported rectangular sandwich plate with porosities. The objective of the current work is to examine the effects of some key parameters, such as porous ratio, power-law index, and slenderness ratio, on the natural frequencies and damping characteristics.

Glucose-responsive oral insulin delivery platform for one treatment a day in diabetes

Glucose-responsive oral insulin delivery platform for one treatment a day in diabetes

Photocatalytic Crystalline and Amorphous TiO2 Nanotubes Prepared by Electrospinning and Atomic Layer Deposition.

In this work core/shell composite polymer/TiO2 nanofibers and from those TiO2 nanotubes were prepared. First, poly(vinyl alcohol) (PVA) and poly(vinylpyrrolidone) (PVP) fibers were synthetized by electrospinning. They were covered with a 100 nm thick amorphous TiO2 layer by atomic layer deposition at 50 °C. Later the polymer core was removed by two different methods: dissolution and annealing. In the case of dissolution in water, the as-prepared TiO2 nanotubes remained amorphous, while when annealing was used to remove the polymers, the TiO2 crystallized in anatase form. Due to this, the properties of amorphous and crystalline TiO2 nanotubes with exactly the same structure and morphology could be compared. The samples were investigated by SEM-EDX, ATR-IR, UV-Vis, XRD and TG/DTA-MS. Finally, the photocatalytic properties of the TiO2 nanotubes were studied by decomposing methyl-orange dye under UV light. According to the results, crystalline anatase TiO2 nanotubes reached the photocatalytic performance of P25, while amorphous TiO2 nanotubes had observable photocatalytic activity.

Methotrexate-loaded polymeric lipid hybrid nanoparticles (PLHNPs): a reliable drug delivery system for the treatment of glioblastoma

Polymeric lipid hybrid nanoparticles (PHLNPs) are core-shell nanoparticle structures made up of polymer cores and lipid shells that have properties similar to both polymeric nanoparticles and liposomes. Methotrexate (MTX) loaded PLHNPs containing tween 80, phosphatidylcholine, poly D, L-lactic-co-glycolic acid (PLGA) and glyceryl tripalmitate prepared using solvent injection and homogenisation method for a glioblastoma treatment option. The MTX-loaded PLHNPs optimised by Box–Behnken design to minimise particle size, higher entrapment efficacy and maximise MTX concentration in the brain at 4 h. The particle size, entrapment efficacy, concentration of drug in the brain at 4 h, zeta potential, and AUC(Brain)/AUC(Plasma) ratio were in the range of 173.51–233.37 nm, 70.56–86.34%, 6.38–12.38 μg/mL, 25.78–36.31 mV and 1.02–5.32. In-vitro drug release studies, cellular internalisation of optimised formulation against U-87 MG shows good anticancer effects.

NIR-light triggered dual-cascade targeting core-shell nanoparticles enhanced photodynamic therapy and immunotherapy

Cell and organelle targeting of nanomedicines are two cascade processes that lead to drug internalization and subsequent enrichment on the final target. However, it is still challenging to achieve dual-cascade targeting (DCT) with high spatiotemporal precision and efficiency via sequential activation of nanomedicine. Herein, we developed DCT core-shell nanoparticles triggered by near infrared (NIR) light for optimized photodynamic therapy (PDT) and immunotherapy. To obtain the DCT core-shell nanoparticles, an aggregation induced emission (AIE) monomer (7) with two hydroxyl groups was first synthesized. Thereafter, two core polymers with either reactive oxygen species (ROS) generation or mitochondrial targeting ability, and a shell polymer with cell surface targeting were synthesized. Assembly of the core polymers and subsequent coating with the shell polymer formed DCT core-shell nanoparticles (NP4). After NP4 were i.v. injected into mice, they were efficiently accumulated at tumor sites. Upon NIR light irradiation, NP4 induced robust ROS generation with concomitant detachment of negative shell polymers with polyethylene glycol (PEG), resulting in charge reversal and the positively charged core nanoparticles for mitochondrial targeting. Subsequently, ROS generated in mitochondria upon continuous light irradiation killed cancer cells via PDT. In addition, PDT induced immunogenic cell death (ICD), thus activating adaptive immunity. This work provided a novel strategy for nanoparticles with DCT capacity to maximize the effectiveness of combined photodynamic and immunotherapy.

Tenoxicam-loaded polymeric micelles material: Formulation, optimization, and evaluation

The objective of the current study was to encapsulate Tenoxicam a poorly soluble drug within self-assembled polymeric micelles created from amphiphilic block copolymer poloxamer 407 to enhance its solubility and thus increasing oral bioavailability. Thin-film hydration technique was adapted in preparation of Tenoxicam loaded polymeric micelles based on different ratios of copolymer poloxamer 407 (ranging from 1:5 up to 1:90), selection of the best micellar formula was based on the values of entrapment efficiency (EE%), particle size (PS), polydispersity index (PDI), and rate of in vitro drug release, then lyophilization was done for selected formula. Prepared micellar solutions (PM1-PM10) were characterized and the best formula PM6 was chosen according to good EE% (84.05%), smaller particle size (33.07 ± 2.23 nm), lower PDI value (0.155), and higher in vitro drug release (81.43% ± 0.048), which further lyophilized and subjected for powder characterization. Fourier transform infrared spectroscopy (FTIR) and differential scanning calorimetry (DSC) indicated that TNX was encapsulated in polymeric micelle core, due to the disappearance of a characteristic peak of TNX. Saturated solubility of PM6 lyophilized powder showed an increase in aqueous solubility (122 times) compared with pure drug, while transmission electron microscopy (TEM) showed the polymeric micelles in images with a spherical structure, smooth surface, uniform particle size, and homogeneous distribution in an aqueous medium. It was concluded that the prepared amphiphilic copolymer micelles loaded with TNX exhibited significant improvement in drug solubility and consequently may enhance oral bioavailability and suggested to be used to prepare solid oral dosage form as an alternative to the marketed one with lower dose size and reduce drug side effects.

Lipid Polymeric Hybrid Nanoparticles: Formulation Techniques and Effects on Glioblastoma

Introduction: In the pharmaceutical industry, liposomes and polymeric nanoparticles are the two most commonly studied delivery vehicles. A new technique uses lipid-polymeric hybrid nanoparticles (LPHNPs) with a polymeric core, and a shell made up of lipid-lipid-PEG lipids. They have properties which complement polymer nanoparticles and liposomes, and they have the potential to improve the physical stability and biocompatibility of the active pharmaceutical ingredient encapsulated in them. Evaporating the solvent from a dual-phase solution containing lipid and polymer is one of the most effective methods for producing the lipid polymeric hybrid nanoparticles. The LPHNPs applications has also been significantly expanded to include combinational and active targeted drug delivery, as well as delivery of genetic materials, vaccines, and diagnostic imaging agents, in addition to single drug delivery for anticancer therapy, like Glioblastoma. Main goal: The main agenda of this compilation was to address the effects of LPHNPs on Glioblastoma treatment. This compilation also highlights some of the formulation techniques and issues that arise during the preparation of LPHNPs. This review also discusses recent developments in core-shell lipid-polymer hybrid nanoparticles, which were conferred in considerable detail later in this article. Conclusion: The main issue which arises while using nanoparticles with polymer is entrapment efficiency. Because of their hybrid components, LPHNPs have proven to solve this problem to a large extent. The recent research trends suggest that lipid polymeric hybrid nanoparticles will prove to be highly effective or productive in treating diseases such as Glioblastoma.

Microstructure and performance of epoxy asphalt binders modified by core-shell rubbers containing different core polymers

Core-shell rubber (CSR) is a good candidate for toughening epoxy asphalt binders. However, the knowledge of the effect of the core polymer on the performance of CSR modified hot-mix epoxy asphalt binder (HEAB) is not completed and systematic yet. In this paper, CSR modified HEABs were prepared by the incorporation of 2 wt% CSR particles with different core polymers, which were in turn subjected to viscous measurements, confocal microscopy, thermogravimetric analysis, dynamic mechanical analysis and tensile tests. The results revealed that the viscosity of CSR with styrene-butadiene copolymer (SB) core (CSRSB) modified HEAB is higher than that of CSR with polybutadiene (PB) core (CSRPB) modified HEAB during curing. The shell destruction of CSR particles resulted in the swelling of the core polymers and dispersion of swollen core polymer particles in the epoxy phase in the micron scale along with asphalt particles. The phase separation of CSRPB modified HEAB occurred in the spinodal decomposition mode, which was different from the nucleation and growth mechanism of the neat and CSRSB modified HEABs. The area fraction of swollen PB particles in the CSR modified HEAB was greater than that of swollen SB particles. The core polymer had a negligible effect on the thermal stability of CSR modified HEABs. The glass transition temperatures of epoxy and asphalt, damping ability and mechanical properties of the neat HEAB were increased with the addition of CSR particles. Especially, CSRPB modified HEAB had higher tensile strength and toughness than CSRSB modified HEAB. With 2 wt% CSRPB particles being adding, the tensile strength, elongation at break and toughness of the neat HEAB were increased by 53%, 42% and 110%, respectively.

Gas-phase synthesis of mesoporous films of Ag/C:H:N:O core-satellite nanoparticles for surface-enhanced Raman spectroscopy

Rapid development in the field of detection of biomolecules by surface-enhanced Raman spectroscopy (SERS) is enabled by enormous progress in the nanofabrication that nowadays allows for the tailor-made production of nanomaterials that can serve as effective and reliable SERS-active platforms. Among others, heterogeneous mesoporous coatings constitute an important class of nanomaterials that receives increasing attention. In this study, we investigate the possibility of producing such nanomaterials using a novel, one-step, and fully solvent-free technique. This approach employs the in-flight decoration of gas-phase synthesized C:H:N:O plasma polymer cores with nanometre-sized silver nanoparticles. Such physically produced Ag/C:H:N:O core-satellite nanoparticles upon deposition on a planar substrate spontaneously form mesoporous nanoparticle films with SERS-active Ag nanoparticles evenly distributed on the surface of supporting C:H:N:O cores. As shown, such produced nanomaterials exhibit, due to their structure, the SERS enhancement factor of (1.1 ± 0.2) × 106, i.e., the enhancement factor one order of magnitude higher than the value 1 × 105 typically reported for silver nanostructures prepared by commonly used magnetron sputtering onto planar substrates.