Nanoparticle-polymer Composites Research Articles

Influence of magnetic interactions in iron oxide nanoparticle polymer composites on magnetism and induction heating

Induction heating of composite materials is of great interest in fields such as controlled polymer curing or degradation, self-healing or contactless joining. Ferrimagnetic iron oxide nanoparticle (IONPs) are suitable candidates for a powder additive to provide this inductive heating functionality, while being low-cost, abundant and a well-studied material class. Varying IONP size, morphology or doping facilitates fine-tuning of their heating properties. However, the interactions of such IONP additives in material composites are often neglected and can significantly alter the induction heating mechanism. In this work, we systematically vary the IONP interactions in polydimethylsiloxane composite materials by integrating 1.) dispersed IONPs 2.) supraparticles of IONPs (micrometer-assemblies), and 3.) oven-dried hard agglomerated IONPs. Additionally, these three levels of interaction are investigated for three different IONPs types (dodecahedrally and octahedrally shaped, as well as cobalt-doped). In general, dispersed IONPs reveal a broader hysteresis and therefore a faster heating curve. We highlight that not only IONP characteristics (size, morphology, doping), but also excitation field strength and foremost IONP interactions in the composite materials are parameters that are interdependent regarding induction heating and need to be considered as such for optimization in an application-oriented scenario.

Review of Light-Activated Antimicrobial Nanoparticle–Polymer Composites for Biomedical Devices

Review of Light-Activated Antimicrobial Nanoparticle–Polymer Composites for Biomedical Devices

Microbially Synthesized Polymer-Metal Nanoparticles Composites as Promising Wound Dressings to Overcome Methicillin-Resistance Staphylococcus aureus Infections.

Antimicrobial resistance has been declared one of the top 10 global public health threats. Methicillin-resistant Staphylococcus aureus (MRSA) is a leading cause of recurring skin and soft tissue infections in patients with chronic skin conditions such as diabetic foot infections, making the treatment of the ulcers challenging. Wound dressings combined with metal nanoparticles have been suggested to prevent and treat MRSA-infected wounds. However, these particles are commonly synthesized by chemical approaches. In this study, we developed bio-based silver (Bio-AgNPs) and copper oxide nanoparticles (CuONPs) polymer composites using a microbially produced polyester from the Polyhydroxyalkanoates (PHAs) family. Poly(3-hydroxyoctanoate)-co-(3-hydroxyhexanoate) (PHO) was synthesized by Pseudomonas putida and functionalized in-situ with Bio-AgNPs or ex-situ with CuONPs. PHO-CuONPs films did not inhibit MRSA growth, while a reduction of 6.0 log CFU/mL was achieved with PHO-Bio-AgNPs synthesized from silver nitrate (AgNO3) solution at 3.5 mM. Exposure of human fibroblast cells (HFF-1) to the bioactive films did not induce notable cytotoxicity and genotoxicity, as seen by a viability higher than 79% and no significant changes in basal DNA damage. However, exposure to PHO-Bio-AgNPs induced oxidative DNA damage in HFF-1 cells. No hemolytic potential was observed, while platelet aggregation was promoted and desired for wound healing. Here we demonstrate the biosynthesis of polymer-nanoparticle composites and their potential as bioactive films for MRSA treatment.

Digital Light 3D Printed Bioresorbable and NIR-Responsive Devices with Photothermal and Shape-Memory Functions.

Digital light processing (DLP) 3D printing is a promising technique for the rapid manufacturing of customized medical devices with high precision. To be successfully translated to a clinical setting, challenges in the development of suitable photopolymerizable materials have yet to be overcome. Besides biocompatibility, it is often desirable for the printed devices to be biodegradable, elastic, and with a therapeutic function. Here, a multifunctional DLP printed material system based on the composite of gold nanorods and polyester copolymer is reported. The material demonstrates robust near‐infrared (NIR) responsiveness, allowing rapid and stable photothermal effect leading to the time‐dependent cell death. NIR light‐triggerable shape transformation is demonstrated, resulting in a facilitated insertion and expansion of DLP printed stent ex vivo. The proposed strategy opens a promising avenue for the design of multifunctional therapeutic devices based on nanoparticle–polymer composites.

Magnetic Nanoparticle–Polymer Composites Loaded with Hydrophobic Sensitizers for Photodegradation of Azoic Dyes

Magnetic Nanoparticle–Polymer Composites Loaded with Hydrophobic Sensitizers for Photodegradation of Azoic Dyes

A study on thermal conductivity and thermogravimetric analysis of glass fiber epoxy resin composites modified with silicon carbide and copper nanoparticles

Composite materials are futuristic materials, the strength, properties and applications decides the composition of composite materials. The study of physical, mechanical and thermal properties of composites provides the more scope for their wide applications. Silicon carbide nanoparticles (SiC-NPs) and Carbon nanoparticles (Cu-NPs) Polymer composites are prepared by hand layup machining moulding technique using epoxy resin and glass fibre. The study of thermogravimetric analysis (TGA) was carried using STA 7300 and TGA 8000 for varied % fillers reinforced in glass fibre polymer composites. The weight loss noticed 64.5 to 94.5% in Cu-NPs composites and 44.2 to76.8% weight loss in SiC-NPs at 750 °C. The overall thermal stability observed in SiC-NPs composites and more thermal stability observed in 15% and 20% SiC-NPs composites. There is a less weight loss in SiC-NPs composites as compared to Cu-NPs composites. The study of thermal conductivity was carried out by FOX50 heat flow meter (HFM), for both SiC-NPs and Cu-NPs composites thermal conductivity increases with increase of fillers percentage. SiC-NPs composites have shown higher thermal conductivity values compared to Cu-NPs composites. Results obtained from the FOX 50 HFM have shown that at higher percentage SiC and Cu nanoparticle fillers thermal conductivity increases by 20% compared ERGF composites without fillers.

In situ polymerization monitoring of a diacrylate in an electrically conducting mesoporous nanoparticle scaffold

The properties of nanoparticle–polymer composites strongly depend on the network structure of the polymer matrix. By introducing nanoparticles into a monomer (solution) and subsequently polymerizing it, the formation of the polymer phase influences the mechanical and physicochemical properties of the composite. In this study, semi-conducting indium tin oxide (ITO) nanoparticles were prepared to form a rigid nanoparticle scaffold in which 1,6-hexanediol diacrylate (HDDA), together with an initiator for photo-polymerization, was infiltrated and subsequently polymerized by UV light. During this process, the polymerization reaction was characterized using rapid scan Kubelka–Munk FT-IR spectroscopy and compared to bulk HDDA. The conductivity change of the ITO nanoparticles was monitored and correlated with the polymerization process. It was revealed that the reaction rates of the radical initiation and chain propagation are reduced when cured inside the voids of the nanoparticle scaffold. The degree of conversion is lower for HDDA infiltrated into the mesoporous ITO nanoparticle scaffold compared to purely bulk-polymerized HDDA.Graphical abstract

금속 나노 입자-고분자 복합체로 코팅된 3D 미세 격자의 압축 거동 분석

Microlattice is well known as an efficient structure having a low density which maintains mechanical properties, so microlattice is being applied to the structural design of lightweight material in many industrial fields. In this study, we proposed a core-shell microlattice structure by the conformal coating of a metal nanoparticle-polymer composite in order to enhance the mechanical properties of polymeric microlattice printed by light-based 3D printing method. Polymeric architected microlattice was fabricated using digital light printing, which enabled the printing of complex structures with good surface smoothness. Then, the polymeric microlattice was conformally coated with aluminum nanoparticle-polymer composites. To investigate the effect of the metal nanoparticle-polymer composite coating on the mechanical properties of the microlattice, we studied the compressive behavior of cubic and octet-truss microlattices. As a result, we confirmed that both compressive strength and toughness of the two types of microlattices were effectively increased by coating with aluminum nanoparticle-polymer composites.

Acoustic Field-Assisted Two-Photon Polymerization Process

Abstract This study successfully integrates acoustic patterning with the Two-Photon Polymerization (TPP) process for printing nanoparticle–polymer composite microstructures with spatially varied nanoparticle compositions. Currently, the TPP process is gaining increasing attention within the engineering community for the direct manufacturing of complex three-dimensional (3D) microstructures. Yet the full potential of TPP manufactured microstructures is limited by the materials used. This study aims to create and demonstrate a novel acoustic field-assisted TPP (A-TPP) process, which can instantaneously pattern and assemble nanoparticles in a liquid droplet, and fabricate anisotropic nanoparticle–polymer composites with spatially controlled particle–polymer material compositions. It was found that the biggest challenge in integrating acoustic particle patterning with the TPP process is that nanoparticles move upon laser irradiation due to the photothermal effect, and hence, the acoustic assembly is distorted during the photopolymerization process. To cure acoustic assembly of nanoparticles in the resin through TPP with the desired nanoparticle patterns, the laser power needs to be carefully tuned so that it is adequate for curing while low enough to prevent the photothermal effect. To address this challenge, this study investigated the threshold laser power for polymerization of TPP resin (Pthr) and photothermal instability of the nanoparticle (Pthp). Patterned nanoparticle–polymer composite microstructures were fabricated using the novel A-TPP process. Experimental results validated the feasibility of the developed acoustic field-assisted TPP process on printing anisotropic composites with spatially controlled material compositions.

Effects of Chain Length on the Structure and Dynamics of Semidilute Nanoparticle–Polymer Composites

We use molecular dynamics simulations to study how the chain length affects the structure and segmental dynamics of polymer–nanoparticle (NP) composites at semidilute NP concentrations. For NPs having relatively strong interactions with the polymer, we can approximate the system as an ideal NP dispersion, which isolates the effect of direct interactions among the NPs. By varying both the chain length N and NP concentration, we examine regimes where the chain size (i.e., chain radius of gyration Rg) is small compared to the NP separation d (d/Rg > 1), as well as cases where d/Rg < 1, so that chains readily “bridge” between the NPs. We find that the fraction of such bridging chains in our simulations can be expressed as a universal function of d/Rg. Structurally, the polymers slightly elongate near the NP interface and the chains tend to align their longest axis with the NP interface. We show that the effect of NPs on the chain structure is nearly chain length-independent, whereas the effect on chain alignment extends farther from the NP surface as the chain length increases. Chains that bridge between NPs must significantly elongate when the NP separation is large compared to the chain dimensions (d/Rg > 1). Although these bridging chains have a longer relaxation time than nonbridging chains, they do not make a substantial contribution to the overall nanocomposite segmental relaxation time for the conditions studied because the bridging chains represent only a small fraction of the system. Note that relaxation at the scale of chains may differ for bridging chains. When NP separation is comparable or smaller than the chain size (d/Rg < 1), bridging chains are more prevalent, but their properties are more similar to nonbridging chains than when d/Rg > 1. Accordingly, the variation of the computational glass transition temperature Tg with chain length essentially mirrors the trend for the reference pure polymer melt, where Tg increases with chain length and roughly saturates at large polymer mass. Overall, for the conditions studied, bridging chains are found to have a small impact on the segmental dynamics of nanocomposites.

Reducing end thiol-modified nanocellulose: Bottom-up enzymatic synthesis and use for templated assembly of silver nanoparticles into biocidal composite material

Nanoparticle-polymer composites are important functional materials but structural control of their assembly is challenging. Owing to its crystalline internal structure and tunable nanoscale morphology, cellulose is promising polymer scaffold for templating such composite materials. Here, we show bottom-up synthesis of reducing end thiol-modified cellulose chains by iterative bi-enzymatic β-1,4-glycosylation of 1-thio-β-d-glucose (10 mM), to a degree of polymerization of ∼8 and in a yield of ∼41% on the donor substrate (α-d-glucose 1-phosphate, 100 mM). Synthetic cellulose oligomers self-assemble into highly ordered crystalline (cellulose allomorph II) material showing long (micrometers) and thin nanosheet-like morphologies, with thickness of 5–7 nm. Silver nanoparticles were attached selectively and well dispersed on the surface of the thiol-modified cellulose, in excellent yield (≥ 95%) and high loading efficiency (∼2.2 g silver/g thiol-cellulose). Examined against Escherichia coli and Staphylococcus aureus, surface-patterned nanoparticles show excellent biocidal activity. Bottom-up approach by chemical design to a functional cellulose nanocomposite is presented. Synthetic thiol-containing nanocellulose can expand the scope of top-down produced cellulose materials.

Red-sensitive organic nanoparticle-polymer composite materials for volume holographic gratings with large refractive index modulation amplitudes

We demonstrate volume holographic recording at a wavelength of 640 nm in a photopolymerizable nanoparticle-polymer composite (NPC) film dispersed with ultrahigh refractive index hyperbranched-polymer (HBP) organic nanoparticles. We employ a new photosensitizer-initiator system consisting of cyanine dye, triazine compound and borate salt for efficient radical generation in the red. We investigate the electron transfer and radical generation processes of the system by measuring fluorescence quenching and photopolymerization dynamics to find the optimum composition of the system for volume holographic recording. We show that recorded volume gratings of 0.5-µm spacing possess the saturated peak-to-mean refractive index modulation amplitudes as large as 3×10−2 at a readout wavelength of 640 nm. Our results show the usefulness of photopolymerizable HBP-dispersed NPCs for volume holographic recording materials for various photonic applications including security and color holograms, and volume Bragg grating devices in head-mounted displays.

Optomechanical Processing of Silver Colloids: New Generation of Nanoparticle-Polymer Composites with Bactericidal Effect.

The properties of materials at the nanoscale open up new methodologies for engineering prospective materials usable in high-end applications. The preparation of composite materials with a high content of an active component on their surface is one of the current challenges of materials engineering. This concept significantly increases the efficiency of heterogeneous processes moderated by the active component, typically in biological applications, catalysis, or drug delivery. Here we introduce a general approach, based on laser-induced optomechanical processing of silver colloids, for the preparation of polymer surfaces highly enriched with silver nanoparticles (AgNPs). As a result, the AgNPs are firmly immobilized in a thin surface layer without the use of any other chemical mediators. We have shown that our approach is applicable to a broad spectrum of polymer foils, regardless of whether they absorb laser light or not. However, if the laser radiation is absorbed, it is possible to transform smooth surface morphology of the polymer into a roughened one with a higher specific surface area. Analyses of the release of silver from the polymer surface together with antibacterial tests suggested that these materials could be suitable candidates in the fight against nosocomial infections and could inhibit the formation of biofilms with a long-term effect.

Characterization of mechanical and wear properties of ABS/SiO2 nanoparticles

Objective: In this present work, the SiO2 nanoparticles as filler materials and ABS as a matrix material taken for the injection molding process to prepare the specimens, after that, to study the enhancement of mechanical properties and wear performance of composite materials. Method/Findings: SiO2 nano particles are added to Acrylonitrile Butadiene styrene(ABS) polymer composites at various weight fractions. It is also found that tensile strength, hardness, and wear properties improved in reinforcement. A pin-on-disc type friction and wear monitor (ASTM G99) was employed to evaluate wear behavior of ABS/SiO2 polymer composites. In this experimental study, the input process parameters such as load, sliding distance, and speed are considered and optimized for the composite materials’ properties. Tensile tests and wear tests were conducted to examine, and the properties of the material were studied. Morphology of the fractured material was studied using SEM analysis. The wear debris observed to explore the flacks and groves of the content during wear test for this study Orthogonal array (L9) and control parameters. Applications/Improvements : The significant contributions of this work are the decrease of ultimate strength with increasing content of SiO2 in the composites, and the sliding speed conversed to 45.51% of the wear rate variation. Mechanical and wear properties of ABS/SiO2 nanoparticles polymer composites were studied further. Keywords: ABS; SiO2 Nanoparticles; tensile; hardness; wear; SEM

Very high contrast volume holographic gratings recorded in photopolymerizable nanocomposite materials.

Volume holographic phase gratings possessing the saturated refractive index modulation amplitudes as large as 4.5×10-2 were recorded at a wavelength of 532 nm in a photopolymerizable nanoparticle-polymer composite (NPC) film dispersed with ultrahigh refractive index hyperbranched-polymer (HBP) organic nanoparticles. This prominent result was achieved by a combination of the HBP nanoparticles with triazine and aromatic ring units and an electron donor/acceptor photo-initiator system doped in an acrylate monomer blend with low viscosity. As a result, efficient mutual diffusion of HBP nanoparticles and monomer having their very large refractive index difference took place. Obtained results suggest a potentiality of our newly developed HBP-dispersed NPC gratings as efficient volume holographic optical elements for various photonic applications including wearable headsets for augmented and mixed reality.

Matrix-specific mechanism of Fe ion release from laser-generated 3D-printable nanoparticle-polymer composites and their protein adsorption properties

Nanocomposites have been widely applied in medical device fabrication and tissue-engineering applications. In this context, the release of metal ions as well as protein adsorption capacity are hypothesized to be two key processes directing nanocomposite-cell interactions. The objective of this study is to understand the polymer-matrix effects on ion release kinetics and their relations with protein adsorption. Laser ablation in macromolecule solutions was employed for synthesizing Au and Fe nanoparticle-loaded nanocomposites based on thermoplastic polyurethane (TPU) and alginate. Confocal microscopy revealed a three-dimensional homogeneous dispersion of laser-generated nanoparticles in the polymer. The physicochemical properties revealed a pronounced dependence upon embedding of Fe and Au nanoparticles in both polymer matrices. Interestingly, the total Fe ion concentration released from alginate gels under static conditions decreased with increasing mass loadings, a phenomenon only found in the Fe-alginate system and not in the Cu/Zn-alginate and Fe-TPU control system (where the effects were proportioonal to the nanoparticle load). A detailed mechanistic examination of iron the ion release process revealed that it is probably not the redox potential of metals and diffusion of metal ions alone, but also the solubility of nano-metal oxides and affinity of metal ions for alginate that lead to the special release behaviors of iron ions from alginate gels. The amount of adsorbed bovine serum albumin (BSA) and collagen I on the surface of both the alginate and TPU composites was significantly increased in contrast to the unloaded control polymers and could be correlated with the concentration of released Fe ions and the porosity of composites, but was independent of the global surface charge. Interestingly, these effects were already highly pronounced at minute loadings with Fe nanoparticles down to 200 ppm. Moreover, the laser-generated Fe or Au nanoparticle-loaded alginate composites were shown to be a suitable bioink for 3D printing. These findings are potentially relevant for ion-sensitive bio-responses in cell differentiation, endothelisation, vascularisation, or wound healing.

Manipulation of the Size and Phase Composition of Yttrium Iron Garnet Nanoparticles by Pulsed Laser Post-Processing in Liquid.

Modification of the size and phase composition of magnetic oxide nanomaterials dispersed in liquids by laser synthesis and processing of colloids has high implications for applications in biomedicine, catalysis and for nanoparticle-polymer composites. Controlling these properties for ternary oxides, however, is challenging with typical additives like salts and ligands and can lead to unwanted byproducts and various phases. In our study, we demonstrate how additive-free pulsed laser post-processing (LPP) of colloidal yttrium iron oxide nanoparticles using high repetition rates and power at 355 nm laser wavelength can be used for phase transformation and phase purification of the garnet structure by variation of the laser fluence as well as the applied energy dose. Furthermore, LPP allows particle size modification between 5 nm (ps laser) and 20 nm (ns laser) and significant increase of the monodispersity. Resulting colloidal nanoparticles are investigated regarding their size, structure and temperature-dependent magnetic properties.

Application of functionalised MXene-carbon nanoparticle-polymer composites in resistive hydrostatic pressure sensors

The synthesised and functionalised materials were characterised using TEM, SEM, Raman and P-XRD. The characterisation techniques confirmed that a successful functionalisation of Ti3AlC2, the synthesised and functional groups on the carbon nanoparticles. The TEM and SEM were also used to study the surface morphology of the materials. The pressure sensor was fabricated by depositing the polymer composites on the IDE and different types of pressure sensors were prepared by varying the sensing materials in the composites. Generally, the fabricated sensors, based on the two polymers, Ppy and PVP polymer, have shown a linear relationship between the applied pressure and the relative resistance response in their respective ranges. The best sensitive sensors were f-MC/Ppy bases sensor 0.00232 kPa−1 in a range from 126 to 168 kPa, in a very wide range, 68–168 kPa, the sensitivity of the f-MC/CNPs based sensor was 0.00017 kPa−1. The sensors recoveries and responses time were also studied and all the sensors based on Ppy polymer responded very fast as compare to PVP based sensors, they responded just in one second and the recovery time was between 3 and 5 s. The PVP based sensors found slower to respond and recover as compare to the Ppy based sensors.

Density Modulation of Embedded Nanoparticles via Spatial, Temporal, and Chemical Control Elements.

Nanoparticle polymer composites have enabled material multifunctionalities that are difficult to obtain otherwise. A simple modification to a commercially available resin system enables a universal methodology to embed nanoparticles in resins via spatial, temporal, thermal, concentration, and chemical control parameters. Changes in nanoparticle density distribution are exploited to demonstrate dynamic optical and electronic properties that can be processed on-demand, without the need for expensive equipment or cleanroom facilities. This strategy provides access to the control of optical (cooperative plasmonic effects), electronic (insulator to a conductor), and chemical parameters (multimetal patterning). Using the same composite resin system, the followings are fabricated: i) diffraction gratings with tuneable diffraction efficiencies (10-78% diffraction efficiencies), ii) organic electrochemical transistors with a low drive voltage, and iii) embedded electrodes in confined spaces for potential diagnostic applications.

Direct cell imprint lithography in superconductive carbon black polymer composites: process optimization, characterization and in vitro toxicity analysis

Cell imprint lithography (CIL) or cell replication plays a vital role in fields like biomimetic smart culture substrates, bone tissue engineering, cell guiding, cell adhesion, tissue engineering, cell microenvironments, tissue microenvironments, cell research, drug delivery, diagnostics, therapeutics and many other applications. Herein we report a new formulation of superconductive carbon black photopolymer composite and its characterization towards a CIL process technique. In this article, we demonstrated an approach of using a carbon nanoparticle-polymer composite (CPC) for patterning cells. It is observed that a 0.3 wt % load of carbon nanoparticles (CNPs) in a carbon polymer mixture (CPM) was optimal for cell-imprint replica fabrication. The electrical resistance of the 3-CPC (0.3 wt %) was reduced by 68% when compared to N-CPC (0 wt %). This method successfully replicated the single cell with sub-organelle scale. The shape of microvesicles, grooves, pores, blebs or microvilli on the cellular surface was patterned clearly. This technique delivers a free-standing cell feature substrate. In vitro evaluation of the polymer demonstrated it as an ideal candidate for biomimetic biomaterial applications. This approach also finds its application in study based on morphology, especially for drug delivery applications and for investigations based on molecular pathways.