Nanostructured Polymeric Materials Research Articles

Utilization of a TiO2-CuO Bimetallic/Polyaniline Nanocomposite as a Transducer in a Solid Contact Potentiometric Sensor for the Determination of Vildagliptin.

Current fundamental electrochemical research shows the potential of utilizing polymeric nanostructured materials as ion-to-electron transducers. In this paper, aniline was polymerized in the presence of TiO2 and CuO nanoparticles to yield a bimetallic/PANI nanocomposite. It was applied as a transducer in a carbon paste electrode for the potentiometric determination of vildagliptin in the presence of 18-crown-6-ether as a recognition element. The electrode's potentiometric performance was studied according to the IUPAC guidelines. It exhibited a wide linearity range of 1 × 10-2 M to 1 × 10-8 M, remarkable sensitivity (LOD of 4.5 × 10-9 M), and a fast response time of 10 s ± 1.3. The sensor did not show any potential drift due to the absence of the water layer between the carbon paste and the metallic conductor. This endowed the sensor with high stability and a long lifetime, as 137 days passed without the need to change the carbon paste surface. The electrode was utilized for the determination of the concentration of vildagliptin in bulk, pharmaceutical tablets, and human plasma, with average recovery ranging from 97.65% to 100.03%.

Recent Advances in the Application of ATRP in the Synthesis of Drug Delivery Systems

Advances in atom transfer radical polymerization (ATRP) have enabled the precise design and preparation of nanostructured polymeric materials for a variety of biomedical applications. This paper briefly summarizes recent developments in the synthesis of bio-therapeutics for drug delivery based on linear and branched block copolymers and bioconjugates using ATRP, which have been tested in drug delivery systems (DDSs) over the past decade. An important trend is the rapid development of a number of smart DDSs that can release bioactive materials in response to certain external stimuli, either physical (e.g., light, ultrasound, or temperature) or chemical factors (e.g., changes in pH values and/or environmental redox potential). The use of ATRPs in the synthesis of polymeric bioconjugates containing drugs, proteins, and nucleic acids, as well as systems applied in combination therapies, has also received considerable attention.

Development of Solid-Contact Potentiometric Sensor Utilized Nanocarbon-filled Poly (vinyl chloride) Membrane as Ion-to-electron Transducing Layer

Current fundamental researches in the field of potentiometry demonstrate the perspectives of using polymeric nanostructured materials as ion-to-electron transducers in Solid-Contact Potentiometric Sensors (SCSs). This paper reports the preparation and comparative study of plasticized Poly(Vinyl Chloride) (PVC) membranes modified with fullerene C60, single-walled carbon nanotubes SWCNTs, multiwalled carbon nanotubes, and graphene oxide as the transducing layer in SCSs for the determination of a common local anesthetic drug – procaine hydrochloride (Pro·HCl). As an ion-sensitive (recognizing) layer, a PVC membrane containing highly lipophilic 2-[bis-octadecyl sulfo]-closo-decaborate anions was chosen. The results were discussed in relation to nanofiller’s type and content. The best potentiometric characteristics were obtained for the sensor with the transducing layer containing the hybrid nanofiller SWCNTs/C60. This new sensor of a double-layer PVC membrane configuration exhibited a Nernstian slope (59.2 ± 0.2 mV/decade) in the wide linear range (5×10-7– 1×10-2 M) with the low limit of detection (10-7.1 M), fast response time (≤ 7 s), and stable potentiometric response (drift potential ± 0.27 mV h-1 over 7 h of soaking in 1x10-5 M Pro·HCl solution).

Modified Thermosets – A Review

Recent and extensive reports on the development of preparation methods that can lead to obtaining various nanostructured polymeric materials, including the preparation of nanoparticles, nano-capsules, nano-gels, nano-fibres, dendrimers and nano-composites, have been presented in the literature to provide a picture of the complexity of the field, and the diversity of approaching methods. From the data presented by various researchers, it appears that by ensuring a rigorous control of the nano-structuration of polymers and/or by adding nano-particles to the polymer matrices, improvements in structural and functional properties can be achieved in a significant number of polymer systems as a response to the continuous demands of industrial advanced sectors. Until now, most of the studies on polymer blends have been related to the control of their physical and chemical properties, their barrier properties or their electrical conductivity. This paper briefly presents various applications of resins (thermoset polymers) used to synthesize some polymer materials and blends.

Advanced insulating materials contributing to “carbon neutrality”: Opportunities, issues and challenges

Advanced insulating materials contributing to “carbon neutrality”: Opportunities, issues and challenges

A methodology for determining the local mechanical properties of model atomistic glassy polymeric nanostructured materials

We propose a methodology for calculating the distribution of the mechanical properties in model atomistic polymer-based nanostructured systems. The use of atomistic simulations is key in unravelling the fundamental mechanical behavior of composite materials. Most simulations involving the mechanical properties of polymer nanocomposites (PNCs) concern their global (average) properties, which are typically extracted by applying macroscopic strain on the boundaries of the simulation box and calculating the total (global) stress by invoking the Virial formalism over all atoms within the simulation box; thus, extracting the pertinent mechanical properties from the corresponding stress-strain relation.However, in order to probe the distribution of mechanical properties within heterogeneous multi-component polymer-based systems, a detailed computation of stress and strain fields within specific sub-domains is necessary. For example, it is well known for multi-component nanostructured systems, such as PNCs, that the mechanical behavior of the polymer/nanofiller interphases, or interfaces, is crucial for determining the global mechanical properties of the composite materials. Here we propose a new methodology to probe the distribution of mechanical properties by directly computing the (local) stress and strain at the atomic level, and averaging over user-defined subdomains. The workflow of our computational method possesses the following features:•Calculating the stress and strain per atom (or per particle) for nanostructured microscopic (here atomistic) model configurations, under an imposed applied deformation.•Averaging the local, per-atom defined, stress and strain on user-defined subdomains within the nanostructured model system.•Predicting the mechanical properties within the specific subdomains, focusing on polymer/solid interphases.

Numerical Study on Broadband Antireflection of Moth-Eye Nanostructured Polymer Film with Flexible Polyethylene Terephthalate Substrate

The application of moth-eye nanostructured polymer film on the flexible polyethylene terephthalate (PET) substrate is an effective way to improve its antireflection (AR) performance. However, many factors affect the AR properties of the moth-eye structure in the actual manufacturing process. Moreover, the antireflection research based on PET substrate has been relatively lacking compared with the silicon substrate. In this paper, we simulate and analyze the AR performance of the moth-eye nanostructured polymer film on PET substrate by using the finite-difference time-domain method within the wavelength range of 400–1100 nm. Simulation results show that the parabola-shaped moth-eye structure (PSMS) can suppress the Fresnel reflection significantly. Moreover, the height and filling ratios are the dominant factors that affect the AR performance of PSMS. Additionally, the base diameter, residual layer thickness, and the refractive index of PSMS polymer film also affect the reflectivity of PET slightly. As a result, an optimal PSMS with base diameter of 400 nm, height of 300 nm, and the hexagonal close-packed arrangement is appropriate, and the solar-weighted reflectivity of PET can be suppressed to 0.21%, which shows a prominent advantage over the bare PET (≈6%). Therefore, this research has promising potential for improving the optical performance of optoelectronic devices by using nanostructured polymer materials.

Liquid Phase Electron Microscopy Provides Opportunities in Polymer Synthesis and Manufacturing

Liquid phase electron microscopy (LP-EM) is a rapidly developing method for imaging chemical processes in solution. A key strength of this method is that the high energy electrons can be used as both an energy and illumination source. This enables simultaneous control of the chemistry with nanoscale structural characterization. As electron beams are widely used in the manufacturing of polymeric materials, we believe that the knowledge obtained from LP-EM can directly guide industrial electron beam technologies, enabling the design, optimization, and manufacturing of nanostructured polymeric materials. In this Perspective, we outline the advances made in electron beam synthesis of polymeric materials and discuss the challenges and opportunities for utilizing LP-EM in conjunction with electron beam manufacturing technologies.

Collagen Pentablock Copolymers Form Smectic Liquid Crystals as Precursors for Mussel Byssus Fabrication.

Protein-based biological materials are important role models for the design and fabrication of next generation advanced polymers. Marine mussels (Mytilus spp.) fabricate hierarchically structured collagenous fibers known as byssal threads via bottom-up supramolecular assembly of fluid protein precursors. The high degree of structural organization in byssal threads is intimately linked to their exceptional toughness and self-healing capacity. Here, we investigated the hypothesis that multidomain collagen precursor proteins, known as preCols, are stored in secretory vesicles as a colloidal liquid crystal (LC) phase prior to thread self-assembly. Using advanced electron microscopy methods, including scanning TEM and FIB-SEM, we visualized the detailed smectic preCol LC nanostructure in 3D, including various LC defects, confirming this hypothesis and providing quantitative insights into the mesophase structure. In light of these findings, we performed an in-depth comparative analysis of preCol protein sequences from multiple Mytilid species revealing that the smectic organization arises from an evolutionarily conserved ABCBA pentablock copolymer-like primary structure based on demarcations in hydropathy and charge distribution as well as terminal pH-responsive domains that trigger fiber formation. These distilled supramolecular assembly principles provide inspiration and strategies for sustainable assembly of nanostructured polymeric materials for potential applications in engineering and biomedical applications.

Tunable thermoelectric properties of free-standing PEDOT nanofiber film through adjusting its nanostructure

Recently, organic thermoelectric (TE) materials have attracted increasing attention in green energy conversion. However, researches on polymer nanostructured TE materials are still scarce, especially for the 1 D nanostructured polymer materials. In this work, 1D poly(3,4-ethylenedioxythiophene) (PEDOT) nanofiber was synthesized by a self-assembled micellar soft-template approach using anionic surfactant sodium dodecyl sulfate (SDS). Then, a flexible and free-standing PEDOT nanofiber film was prepared through a simple vacuum-assisted filtration method. FE-SEM and TEM characteristics real 1D configuration for all the PEDOT nanostructures. Through adjusting the molar ratio of SDS, oxidizing agent FeCl3 and EDOT monomer (nSDS: nFeCl3: nEDOT), nanofiber with different diameter (10–200 nm) and microtopography can be obtained. Electrical conductivity and Seebeck coefficient measurement indicates that the TE properties of PEDOT can be effectively tuned by adjusting its nanostructure, and a variation range as high as three orders of magnitude for the power factors (10-2–101 μW/mK2) can be realized. Due to a more ordered structure caused by the edge-on packing mode of PEDOT chain, the sample prepared with nSDS: nFeCl3: nEDOT = 30:15:7 shows the highest power factor of 7.2 μW/mK2. This value can be further enhanced to 14.4 μW/mK2 by constructing PEDOT nanofiber/SWCNTs composite.

Engineered Hybrid Materials with Smart Surfaces for Effective Mitigation of Petroleum-Originated Pollutants

• Petroleum-originated pollutants and their effective mitigation is reviewed. • The persistence of toxic substances causes threats to the living ecosystems. • Effective remediation of contaminated environment is of supreme interest. • Hybrid materials with smart surfaces are effective to remediate hydrocarbons. The generation and controlled or uncontrolled release of hydrocarbon-contaminated industrial wastewater effluents to water matrices are a major environmental concern. The contaminated water comes to surface in the form of stable emulsions, which sometimes require different techniques to mitigate or separate effectively. Both the crude emulsions and hydrocarbon-contaminated wastewater effluents contain suspended solids, oil/grease, organic matter, toxic elements, salts, and recalcitrant chemicals. Suitable treatment of crude oil emulsions has been one of the most important challenges due to the complex nature and the substantial amount of generated waste. Moreover, the recovery of oil from waste will help meet the increasing demand for oil and its derivatives. In this context, functional nanostructured materials with smart surfaces and switchable wettability properties have gained increasing attention because of their excellent performance in the separation of oil–water emulsions. Recent improvements in the design, composition, morphology, and fine-tuning of polymeric nanostructured materials have resulted in enhanced demulsification functionalities. Herein, we reviewed the environmental impacts of crude oil emulsions and hydrocarbon-contaminated wastewater effluents. Their effective treatments by smart polymeric nanostructured materials with wettability properties have been stated with suitable examples. The fundamental mechanisms underpinning the efficient separation of oil–water emulsions are discussed with suitable examples along with the future perspectives of smart materials.

Design and Synthesis of Nanostructured Materials for Sensor Applications

There has been an increasing demand for the development of sensor devices with improved characteristics such as sensitivity, low cost, faster response, reliability, rapider recovery, reduced size, in situ analysis, and simple operation. Nanostructured materials have shown great potential in improving these properties for chemical and biological sensors. There are different nanostructured materials which have been used in manufacturing nanosensors which include nanoscale wires (capability of high detection sensitivity), carbon nanotubes (very high surface area and high electron conductivity), thin films, metal and metal oxide nanoparticles, polymer, and biomaterials. This review provides different methods which have been used in the synthesis and fabrication of these nanostructured materials followed by an extensive review of the recent developments of metal, metal oxides, carbon nanotubes, and polymer nanostructured materials in sensor applications.

Gas-separation and physical properties of ABA triblock copolymers synthesized from polyimide and hydrophilic adamantane derivatives

In this study, ABA triblock copolymers derived from 4,4’-(hexafluoroisopropylidene)-diphthalic anhydride-2,3,5,6-tetramethyl-1,4-phenylenediamine (6FDA-TeMPD; PI) and 3-hydroxy-1-adamantyl methacrylate (HAdMA) or 3,5-dihydroxy-1-adamantyl methacrylate (DHAdMA) have been synthesized via atom transfer radical polymerization to generate mechanically tough and thermally stable gas-separation membranes with composition-tunable transport properties. Due to the inherent thermodynamic incompatibility between the chemically dissimilar blocks, these two series of triblock copolymers appear microphase-separated. While the gas permeability coefficients of these triblock copolymer membranes are consistently lower than that of PI due to the reduced fractional free volume of HAdMA and DHAdMA, the solubility coefficients of the copolymers are higher than that of PI due presumably to specific interactions between the polar hydroxyl group(s) and penetrant gas molecules. These triblock copolymers synthesized from PI and hydrophilic adamantane derivatives constitute a new class of nanostructured polymeric materials possessing excellent thermomechanical properties in conjunction with designer gas-separation properties.

Amorphous flexible covalent organic networks containing redox-active moieties: a noncrystalline approach to the assembly of functional molecules.

The organization states of functional molecules have a significant impact on the properties of materials. A variety of approaches have been studied to obtain well-organized molecular assemblies. The present work shows a new non-organized state of isolated and dispersed functional molecules in amorphous flexible covalent organic networks. Redox-active quinone molecules are embedded in the amorphous network polymers. Consecutive reactions between benzoquinone (BQ) and linker molecules generate random network structures through polymerization at different rates and in multiple directions. The low-crystalline stackings of the amorphous network polymers facilitate the formation of nanoflakes through exfoliation in dispersion media. Enhanced electrochemical performances, one of the highest specific capacities in recent studies, were achieved by efficient redox reactions of the quinone moiety. The present noncrystalline approach, low-crystalline stacking of designer amorphous covalent organic networks, can be applied to construct similar nanostructured polymer materials containing functional units.

Nanoscale DMA with the Atomic Force Microscope: A New Method for Measuring Viscoelastic Properties of Nanostructured Polymer Materials

We introduce nanoscale dynamic mechanical analysis (DMA) based on atomic force microscopy (AFM), a new mode for quantitative viscoelastic analysis of heterogeneous polymer materials at the nanoscale (AFM-nDMA). AFM-nDMA takes advantage of the exquisite force sensitivity, small contact radius, and nanoscale indentation depth of the AFM to provide dynamic mechanical analysis with 10 nm spatial resolution at rheologically relevant frequencies and variable temperature. This novel, non-resonant measurement is embedded in a force curve and typically occurs at a series of frequencies to provide spectra of storage modulus, loss modulus, and loss tangent. By using tailored probes and mitigating the effect of contact radius changes throughout the measurement, quantitative results are obtained that tie directly to bulk DMA and allow for time–temperature superposition analysis. The combination of quantitative results and 10 nm spatial resolution holds promise for the investigation of previously inaccessible microscopic domains, confinement effects, and interphases.

Shell Architecture Strongly Influences the Glass Transition, Surface Mobility, and Elasticity of Polymer Core-Shell Nanoparticles.

Despite the growing application of nanostructured polymeric materials, there still remains a large gap in our understanding of polymer mechanics and thermal stability under confinement and near polymer–polymer interfaces. In particular, the knowledge of polymer nanoparticle thermal stability and mechanics is of great importance for their application in drug delivery, phononics, and photonics. Here, we quantified the effects of a polymer shell layer on the modulus and glass-transition temperature (Tg) of polymer core–shell nanoparticles via Brillouin light spectroscopy and modulated differential scanning calorimetry, respectively. Nanoparticles consisting of a polystyrene (PS) core and shell layers of poly(n-butyl methacrylate) (PBMA) were characterized as model systems. We found that the high Tg of the PS core was largely unaffected by the presence of an outer polymer shell, whereas the lower Tg of the PBMA shell layer decreased with increasing PBMA thickness. The surface mobility was revealed at a temperature about 15 K lower than the Tg of the PBMA shell layer. Overall, the modulus of the core–shell nanoparticles decreased with increasing PBMA shell layer thickness. These results suggest that the nanoparticle modulus and Tg can be tuned independently through the control of nanoparticle composition and architecture.

Multifunctional polymer materials with antifungal activity, modified by fluorocarbon films by methods of ion-plasma technology

The formation of fluorocarbon coatings from plasma-forming mixtures CF4 + C6H12 and C4F8 + C6H12 on the surface of polyethyleneterephthalate and polystyrene using ion-plasma technology are considered. Nanostructured polymer materials have increased fungi resistance and high optical characteristics.

Modelling of novel polymer materials through atomistic molecular dynamics simulations

Molecular simulation methodologies are nowadays very important tools for the prediction of structure-properties relations of molecular systems, and, more general, for the computational design of novel materials. Here, we demonstrate that the atomistic molecular dynamic simulations can be successfully used to design well-defined polymer systems as well as to examine their structural and dynamical properties. More specifically, we study the behaviour of graphene-based nanocomposites and nanostructured polymer materials. We provide a detailed analysis adapted to every system with a special focus on detecting the local heterogeneities in the material. Our carefully developed method allows us to shed light on the relation between the local structure and final properties of the desired material. The obtained information can be applied in the development of novel complex multi-phase polymeric materials with a broad range of possible applications, as for instance in energy storage and electronics.

Quantum dynamical studies of ultrafast charge separation in nanostructured organic polymer materials: Effects of vibronic interactions and molecular packing

AbstractWe review recent work employing high‐dimensional quantum dynamical techniques to study ultrafast charge separation in functional organic materials, in view of understanding the key microscopic factors that lead to efficient charge generation in photovoltaics applications. As highlighted by recent experiments, these processes can be guided by quantum coherence, despite the presence of static and dynamic disorder. The present approach combines first‐principles parametrized lattice Hamiltonians, based on Time‐Dependent Density Functional Theory (TDDFT) and/or high‐level electronic structure calculations, with accurate quantum dynamics simulations using the Multi‐Configuration Time‐Dependent Hartree (MCTDH) method. This contribution specifically addresses the mechanism of charge generation in (i) regioregular oligothiophene‐fullerene aggregates, and (ii) highly ordered oligothiophene‐perylene diimide co‐oligomer assemblies. These studies highlight that chemical design of donor–acceptor combinations needs to account for the effects of electronic delocalization and the modified energetics due to molecular packing, as well as multiple transfer pathways and internal conversion channels induced by vibronic interactions.

Blowing agent free generation of nanoporous poly(methylmethacrylate) materials

In this article, we demonstrate a newly developed technique for generation of nanoporous polymer materials. Generally, the production processes of polymeric nanostructured materials require high pressure due to the handling of gaseous blowing agents. Our new approach allows to generate nanoporous polymer materials without blowing agent at ambient conditions. Starting from a crosslinked polymer gel swollen with a mixture of at least two specially selected solvents leads to a nanoporous material by sequential evaporation. We varied the pore size of the generated structures between 80 and 800 nm so that the effect of the pore size on the gaseous thermal conductivity could be analyzed. Decreasing the pore size of the materials, the gaseous thermal conductivity could be reduced considerably. Thus, we developed a blowing agent free technique which allows the generation of nanoporous polymer materials—Knudsen materials—at an ambient pressure.