Nanofilled Composites Research Articles

Contemporary, Multidisciplinary Roles of Mesoporous Silica Nanohybrids/Nanocomposites

AbstractNumber of nanomaterials have been produced as a result of the growth of nanoscience and nanotechnology, and have found applications in interdisciplinary sectors in which nanotechnology has now become indispensable. Owing to the better properties over individual nanomaterials, the hybrid materials have been broadly studied. Mesoporous silica nanoparticles (MS Nps) have been employed as a matrix in the synthesis of nanohybrids and as a filler in nanocomposites due to its high porosity, adjustable pore volume, facile functionalization, thermal and chemical stability and less toxicity. So far, versatile MS Nps hybrids and composites have been synthesized as advanced smart materials to be applied across industrial and biological sectors. This review study gives an up‐to‐date viewpoint on the synthesis and uses of mesoporous silica nanohybrids and nanocomposites particularly in biomedical sectors, agricultural and food industries and in environmental remediation followed by future insights and research directions of MS Np hybrids and composites.

Features of the Transport Properties of Thermoelectric Nanocomposites Based on a Matrix from BiSbTe1.5Se1.5 Medium-Entropy Alloy and Carbon-Nanotube Filler

For the first time, thermoelectric nanocomposites consisting of a BiSbTe1.5Se1.5 medium-entropy alloy (nanocomposite matrix) and “Taunit-M”, CNT carbon nanotubes (nanocomposite filler)are obtained. All BiSbTe1.5Se1.5 + xCNT nanocomposites with different filler contents (x = 0, 0.05, 0.1, 0.5, 1.0, 1.5, and 2.0 wt %), obtained by spark plasma sintering of the initial powders of the matrix material and filler, consist of micron-sized filler inclusions formed from clusters of nanotubes. The inclusions themselves are randomly distributed within the polycrystalline matrix. In the temperature range of 290–500 K, the transport properties (electrical resistivity and total thermal conductivity, including the electronic and phonon contributions, as well as the contribution of bipolar thermal conductivity) of the nanocomposites with various filler contents are studied. It is established that the introduction of CNTs into the matrix leads to a qualitative change in the type of electrical conductivity from “metallic” (electrical resistance increases with temperature), characteristic of the nanocomposite matrix, to “semiconductor” (resistance decreases with temperature), characteristic of nanocomposites. The observed “semiconductor” behavior of the electrical conductivity is characteristic of electrically inhomogeneous systems, in which current transfer is determined by the movement of electrons through the interfaces between the inhomogeneities. For all nanocomposites with different filler contents, the temperature dependences of the total thermal conductivity are qualitatively similar. At low temperatures, they are determined by the phonon contribution; at high temperatures, by the bipolar-thermal-conductivity contribution; the electronic contribution manifests itself at all temperatures, but it gradually decreases with increasing x. The minimum thermal conductivity is observed for the nanocomposite with x = 0.5 at % CNT.

Comparison of a resin-based sealant with a nano-filled flowable resin composite on sealing performance of marginal defects in resin composites restorations: a 36-months clinical evaluation

Our goal was to evaluate the clinical behavior of resin-based composite (RBC) restorations with sealed marginal defects using nano-filled flowable RBCs (FRS) compared with resin-based sealant (RBS); this work used marginal adaptation, marginal staining, and secondary caries according to the World Dental Federation (FDI) criteria. This was a prospective, randomized, double-blind, controlled trial. Fifty-four patients who met the inclusion criteria (older than 18years old; with high cariogenic risk determined by Cariogram software; and restorations with marginal defects, 3 and 4 according to FDI criteria) were randomly divided into three groups. There were three defective RBC restorations per patient and were repaired (n = 162). The groups were RBS-marginal sealing using a resin-based sealant (Clinpro Sealant, 3M ESPE, MN, USA) plus adhesive (Single Bond Universal, 3M ESPE, MN, USA); FRS-sealing using flowable resin (Filtek Flow Z350XT, 3M ESPE, MN, USA) plus adhesive (Single Bond Universal, 3M ESPE, MN, USA); and control-no repair treatment. All procedures were performed under complete isolation. Evaluations were evaluated at 1-week post treatment (baseline) as well as at 18 and 36months after treatment regarding marginal adaptation, marginal staining, and secondary caries according to FDI criteria. The data were analyzed using the Wilcoxon test (α = 0.05) to compare the differences in each treatment group at different evaluation times. Marginal adaptation of micro-repaired RBC restorations were seen in patients with a high risk of caries using flowable resin composite or resin-based sealants. There were differences (P < 0.001) when baseline was compared at 18 and 36months. Marginal staining showed differences when baseline was compared to 18months (P < 0.001) and 36months (P = 0.001) for both treatments. Secondary caries parameters for RBS treatment showed differences when baseline was compared to 36months (P = 0.025) and when 18months was compared to 36months (P = 0.046). Micro-repair of RBC restorations resulted in clinical deterioration of marginal adaptation and marginal staining. Nano-filled flowable resin composites were sealed on defective restorations; 3 and 4 FDI marginal defects have better clinical performance to prevent secondary caries than resin-based sealants after 36months. Micro-repair with RBS does not seem to be an effective treatment to prevent secondary caries.

Polymer/Layered Silicate Nano-composites

Abstract Polymer/layered filler nano-composites (PLFNCs) offer remarkably improved mechanical properties with low inorganic filler loading. Major developments in this field have been carried out over the last one and half decades. However, we are far from the goal of understanding the mechanisms of the enhancement effects in nanocomposites. Continued progress in nanoscale control, as well as an improved understanding of the physicochemical phenomena at the nanometer scale, has contributed to the rapid development of novel PLFNCs. We describe nano-structure development and processing operations in PLFNCs.

Microhardness Evaluation of Microhybrid Versus Nanofilled Resin Composite After Exposure to Acidic Drinks.

ABSTRACTObjective:To investigate the effect of two acidic agents on microhardness of nanofilled and microhybrid resin composite materials.Materials and Methods:70 resin composite discs (10 mm diameter and 2 mm thick) were prepared from 2 resin composites (35 from each type), nanofilled (Z350XT) and microhybrid (Z250), 3M/ESPE. Ten discs (5 from each group) were used as control (tested at 1 h before immersion). Each group was divided into 3 subgroups (n = 10) according to the storage media: distilled water (control), box-type cola and orange juice. Each subgroup was further subdivided into 2 divisions (n = 5) according to microhardness testing at 24 h and 7days after immersions. Digital Vickers Microhardness Tester (FM-7, Future Tech, Tokyo, Japan) was used to measure surface microhardness with a Vickers diamond indenter. The surface of the specimens received a load of 200 g for 10 seconds. Three indentations not less than 1 mm from each other were placed on the surface of all specimens. Vickers hardness number (VHN) was calculated for each indentation Data were statistically analyzed using one- way ANOVA followed by Newman-keuls tests (P ≤ 0.05).Results:Orange juice showed statistically significantly the lowest VHN mean value (92.7) followed by the Cola group (95.15) then the water group (104.02) compared to the control group (117.4). Microhybrid composite groups showed statistically significant higher VHN mean value (108.1) than the nanofilled composite (100.2). The 7days groups showed statistically significant lower VHN mean value (97.3) than 24h groups (106.6).Conclusions:All storage media reduced hardness of resin composites with orange juice showing the highest reduction in hardness values. Microhybrid is more resistant to degradation than nanofilled composite. Over time, microhardness of resin composites decreased progressively.

The development of the real-time Michelson interferometer for the measurement of thermal expansion coefficients of dental composites nanofiller

This study aims to design a thermal time-based expansion coefficient sensor system using a nickel interferometer that uses a 6 Watts heater to produce a similar oral cavity temperature of 30°C to 60°C. The light source used was the He-Ne Laser, with a wavelength of 632.8 nm. Hollow cylindrical samples with an outer diameter of 1.1 cm, an inner diameter of 1 cm, and a height of 1.5 cm were placed in the sample box behind one of the Michelson Interferometer mirrors. The interference pattern (fringes) formed was recorded using a webcam and counted using the principle of motion detection in the Delphi program. The temperature sensor used was LM 35 with LM 358 amplifier. The resulting voltage output was converted to a temperature value with Arduino. The data were then displayed on a PC with the Delphi interface. The purposely written Delphi program has four functions: recording and counting fringes, displaying temperature, and calculating the thermal expansion coefficient of acrylic resin and nanofiller composite. The generated data in the study included the heating time for 25,421 seconds to produce a temperature of 60°C, delay of (0,802 ± 0,006) second with the sensor performance of 99,76%, and software performance of 98,18%. In three data collections, the average thermal expansion coefficient of resin acrylic was (111.37 ± 10.93). 10-6 / ° C with an error percentage of 23.74% from the literature, while for the composite nanofiller samples, we obtained (49.6 ± 0.95). 10-6 / ° C with an error percentage of 6.9% from previous studies.

Effect of Air-Polishing and Different Post-Polishing Methods on Surface Roughness of Nanofill and Microhybrid Resin Composites.

Air-abrasion is a popular prophylactic procedure to maintain oral hygiene. However, depending on the applied air-abrasive powder, it can damage the surface of the tooth and restorations, making it susceptible to plaque accumulation. The purpose of this study was to investigate the effect of 5 s and 10 s air-abrasion of calcium carbonate on surface roughness (Ra) of enamel, nanofill, and microhybrid resin-composites and the effect of post-polishing with two-step rubber- (RP) or one-step brush polisher (BP) to re-establish the surface smoothness. Surface topography was visualized by scanning-electron-microscopy. The quantitative measurement of the Ra was carried out with atomic-force-microscopy. Air-abrasion for 10 s decreased the Ra of enamel as a result of abrasion of the natural surface texture. Post-polishing with RP after 10 s air-abrasion did not change the Ra or BP; however, Ra was increased significantly by scratching the surface. Air-abrasion increased the Ra of resin composites significantly, irrespective of the application time. While RP provided a similarly smooth surface to the control in the case of microhybrid resin composite, BP increased the Ra significantly. The Ra for the control group of the nanofill-resin composite was initially high, which was further increased by air-abrasion. RP and BP re-established the initial Ra with deeper and shallower scratches after BP. Both the material and treatment type showed a large effect on Ra.

Nano-Composite Filler of Heteropolyacid-Imidazole Modified Mesoporous Silica for High Temperature PEMFC at Low Humidity

Nano-composite filler has received attention for the application to high temperature and low humidity polymer electrolyte membrane (PEM) in fuel cell systems. Heteropolyacids (HPAs) are one of the most attractive materials because of their conductive and thermally stable properties, but have practical limitations due to their high solubility. We investigated the stabilization of HPA on imidazole modified mesoporous silica as a nano-composite filler. The role of mesoporous silica as a support for imidazole and the distribution of chemically bonded HPA on the surface were both confirmed through physical and chemical analysis. The developed nano-composite was utilized to a PEM as a proton conducting filler, cast with commercial AquivionTM solution. Changing the HPA: imidazole ratio and HPA wt%, the composite membrane of Im10/PWA6/Si-MCM-41 (PWA 10 wt%) resulted in higher proton conductivity compared to the non-modified membrane at all operation conditions, especially at high temperature (140 °C) and low relative humidity (RH 10%), with values of 0.3530 and 0.0241 S/m, respectively. A single cell test at H2/Air also showed the effect of adding the nano-composite filler at a wide range of temperatures, which outperformed a single cell with a pristine membrane even at an extremely low humidity condition.

Effect of finishing protocols and staining solutions on color stability of dental resin composites.

ObjectiveThe objective of this study was to evaluate the effect of finishing protocol and exposure to staining solutions on color stability of dental resin composites.Materials and MethodsA nanofill and microhybrid composite, three finishing protocols (mylar, Soflex disc, and white polishing stone) and four staining solutions (tea, red wine, khat extract—two concentrations, control—distilled water) were evaluated. A digital spectrophotometer was used for color change (ΔE) measurements employing the CIE‐Lab‐color system. Paired/independent‐sample t test and two‐way analysis of variance (ANOVA) followed by Tukey's honestly significant difference posthoc test were used for inferential statistics at α = .05.Results Soflex finish was associated with least staining and comparable color stability for the two materials in tea and red wine. In Khat 2, microhybrid composite had statistically significant better color stability than nanofill for Soflex finish (14 days t = 3.270, p = .011). For microhybrid composite, mylar resulted in highest mean ΔE, whereas Soflex recorded the least in all staining solutions. For nanofill composite, white stone resulted in highest mean ΔE, whereas Soflex demonstrated the least mean ΔE in all staining solutions, except red wine where mylar demonstrated the least mean ΔE. For mylar finish, nanofill demonstrated statistically significant better color stability than microhybrid in both red wine (14 days t = 4.902, p = .001) and Khat 1 (14 days t = 3.252, p = .012). For stone finish, microhybrid demonstrated statistically significant better color stability than nanofill in all staining solutions (14 days t ≥ 4.785, p ≤ .001). Two‐way ANOVA showed a statistically significant difference in mean ΔE between and within specimens (F = 42.658, p < .001). All staining solutions caused clinically unacceptable discoloration for mylar and white stone finish. For Soflex finish, red wine produced clinically unacceptable color difference beyond 48 h.ConclusionThere was a difference in color stability of resin composites depending on filler type, further influenced by finishing protocol. Soflex disc finish results in better color stability than mylar and white stone in both microhybrid and nanofill composites.Clinical significanceEsthetic dental restorations such as resin composites are routine in contemporary restorative practice. Color stability of composites may be influenced by surface finish, dependent on the filler type, and consumption of chromogenic substances such as khat. To prolong their service, selection of suitable finishing protocols is an important consideration.

Effect of Erbium, Chromium-doped: Yttrium, Scandium, Gallium and Garnet Laser Tooth Preparation on Gap Formation of Universal Adhesive Bonded to Enamel and Dentin: A Micro-CT and SEM Study.

Introduction: The presence of gaps at the bonding interface of resin composite restorations is known to have an impact on restoration longevity. This study aimed to evaluate the effect of erbium, chromium-doped yttrium, scandium, gallium, and garnet (Er, Cr:YSGG) laser irradiation on gap formation at the tooth-resin interface and to compare the reliability of micro-computed tomography (µCT) and scanning electron microscopy (SEM) scans for gap formation assessment. Methods: Thirty standardized non-retentive class V cavities were prepared on sound human premolars using either an Er,Cr:YSGG laser or a round carbide bur (n=15 for each). A universal adhesive and A nano-filled resin composite were applied in accordance with the manufacturer's recommendations. After water storage for 24 hours at 37°C, the teeth were subjected to thermocycling. Gap formation assessments were performed by µCT (Skyscan 1173 µCT, Brucker, Belgium) and SEM (JEOL JSM-6610LV, Japan), and SPSS version 24.0 (IBM Inc., Chicago, USA) was used to analyze the data at P value<0.05. Descriptive statistics were used to describe the gap formation percentages. To compare the impact of both preparation and assessment methods, a non-parametric Mann-Whitney U test was used. Results: In enamel, similar gap formation values were detected for the two preparation methods (bur and laser). However, the laser-prepared group showed higher gap formation values in dentin. Additionally, higher gap formation values were reported for both preparation methods when µCT was used for assessment. Conclusion: Cavity preparation using a Waterlase laser led to higher gap formation percentages at the dentin-resin interface. In addition, SEM assessment is more reliable for assessing the tooth-resin interface.

Clinical Performance of Direct Composite Restorations in Patients with Amelogenesis Imperfecta - Anterior Restorations.

To evaluate the clinical performance of direct composite restorations using nanohybrid and nanofill composite materials in anterior teeth in patients with amelogenesis imperfecta (AI). The study included 15 patients with AI aged 14-30 years. During the study, the patients received anterior direct composite laminate veneer restorations using either a nanohybrid (Clearfil Majesty ES-2 and Clearfil Universal Bond, Kuraray Noritake) or a nanofill resin composite (Filtek Ultimate Universal Restorative and Single Bond Universal Adhesive, 3M Oral Care). The restorations were evaluated according to the modified USPHS criteria at baseline and at 1-, 2-, 3- and 4-year follow-up periods. The cumulative success rate of anterior restorations was 80.5% for nanohybrid and 92.5% for nanofill composite after 4 years. Eight restorations with nanohybrid and three restorations with nanofill resin composites failed. Ten restorations failed due to fracture; the fracture rate was 12.3%. Statistically significant differences were found between nanohybrid and nanofill composites regarding marginal discoloration and surface texture after 3 years. Furthermore, statistically significant differences were observed with respect to color match after 4 years. The use of a nanohybrid or nanofill composite for anterior direct restorations in patients with AI was observed to be satisfactory, based on the rate of ideal and clinically acceptable restorations. The primary reason for restoration failure was fracture. The failure rate of nanohybrid composite restorations was higher than with nanofill composite restorations with respect to survival and marginal adaptation criteria.

Crosslinking of Pressure-Sensitive Adhesives with Polymer-Grafted Nanoparticles.

Nanocomposite filler particles provide multiple routes to mechanically reinforce pressure-sensitive adhesives (PSAs), as their large surface area to volume ratios provide a means of effectively crosslinking multiple polymer chains. A major advancement could therefore be enabled by the design of a particle architecture that forms multiple physical and chemical interactions with the surrounding polymer matrix, while simultaneously ensuring particle dispersion and preventing particle aggregation. Understanding how such multivalent interactions between a nanoparticle crosslinking point and the PSA polymer affect material mechanical performance would provide both useful scientific knowledge on the mechanical structure-property relationships in polymer composites, as well as a new route to synthesizing useful PSA materials. Herein, we report the use of polymer-grafted nanoparticles (PGNPs) composed of poly(n-butyl acrylate-co-acrylic acid) chains grafted to SiO2 nanoparticle (NP) surfaces to cohesively reinforce PSA films against shear stress without compromising their adhesive properties. The use of acrylic acid-decorated PGNPs allows for ionic crosslinking via metal salt coordination to be used in conjunction with physical entanglement, yielding 33% greater shear resistance and up to 3-fold longer holding times under static load. In addition, the effects of material parameters such as PGNP/crosslinker loading, polymer graft length, and core nanoparticle size on mechanical properties are also explored, providing insights into the use of PGNPs for the rational design of polymer composite-based PSAs.

A composite nanofiller with a nail column void structure to imitate beetle shell fiber to enhance the impact resistance of polyurethane elastomer

Polyurethane elastomer (PUE) is faced with cracking problems under the high-speed impact to limit its application in the protective field. Inspired by a “nail columns"—"nail columns” void structure of chitin fiber on the beetle shell, tetra vinyl polyhedral oligomeric silsesquioxanes (EVPOSS) composite multiwalled carbon nanotube (MCNTs) enhanced fillers (PDVBMC and PNHMC) were prepared by different bonding types and used to improve the impact resistance of PUE. The 1.5 wt% PDVBMC or PNHMC reinforced composite PUE exhibited simultaneous enhancements in maximum compression modulus (22.2% and 34.6%), energy absorption (40.1% and 53.7%) and storage modulus (16.5% and 30.6%). The excellent mechanical properties of composite PUE is not only attributed to the enhancement of interface strength between enhanced fillers and PUE matrix but also the bonding strength between enhanced fillers, which can be demonstrated by the differences in energy absorption, storage modulus and bonding fracture energy.

Nano-dimensional spheres and worms as fillers in polymer nanocomposites: effect of filler morphology

Poly(methyl methacrylate) based polymeric nanofillers are prepared via polymerization induced self-assembly (PISA). Nanofillers with worm-morphology result in more significant improvement in mechanical properties than spherical nanofillers.

A Trial to Estimate the Content and Distribution of Filler in Polymer Nanocomposites by SEM-EDX

A Trial to Estimate the Content and Distribution of Filler in Polymer Nanocomposites by SEM-EDX

Surface gloss, gloss retention, and color stability of 2 nano-filled universal resin composites.

This study compared the surface gloss (SG), gloss retention (GR), and color stability (CS) of 2 universal resin composites after chemical (CA) and mechanical (MA) aging. Twenty disc-shaped samples of G-ænial A´Chord (GC-Europe) and Filtek Universal (3M-ESPE) were polished with sequential abrasive papers. For CA, specimens were stored in 1 mL of 75% ethanol for 15 days at 37°C, and readings (SG, GR, and CS) were obtained at baseline and 5, 10, and 15 days. For MA, specimens were subjected to 10,750 simulated brushing cycles. SG and CS were evaluated after every 3,583 cycles. SG was measured with a glossmeter (geometrical configuration: 60°), and values were expressed in gloss units. Color was measured with a spectrophotometer using the CIE-L*a*b* color system. The Student's t-test, 1-way analysis of variance, and Scheffé test were used for statistical analysis (α = 0.05). G-ænial presented significantly higher SG values than Filtek (p = 0.02), with GR reductions of 5.2% (CA) and 5.3% (MA) for G-ænial and 7.6% (CA) and 7.2% (MA) for Filtek. The aging protocol had no statistically significant effect on SG or GR (p = 0.25) from baseline to the final readings. G-ænial-MA presented the lowest color difference (∆E = 1.8), and G-ænial-CA and Filtek-CA had the largest changes (∆E = 8.6 and ∆E = 11.8, respectively). G-ænial presented higher SG values and better CS. Both restorative materials demonstrated acceptable GR and CS. Aging protocols impacted these properties negatively.

Effect of Hydrogen Peroxide on the Color Stability and Roughness of Nano-Filled Composites: A Literature Review

This research seeks to ascertain the impact of hydrogen peroxide bleaching gel on the color stability and roughness of nano-filled composite restoration. The most important aesthetic elements of restoration are surface gloss, surface roughness, and color. It has been claimed that saliva, food ingredients, and beverages may compromise the integrity and aesthetics of dental composites, causing them to degrade in the mouth. For aesthetic restorations including anterior and posterior teeth, resin co

Influence of Nanosilica Particle Addition on Mechanical and Water Retention Properties of Natural Flax- and Sisal-Based Hybrid Nanocomposites under NaOH Conditions

Organic filament-based lightweight materials are increasingly being used because of their high strength-to-weight ratio, recyclability, and low cost. The application of nanofillers in addition to natural fibres is a fascinating one. The main purpose of the current experimental investigation is to manufacture and estimate the mechanical material of nanocomposites. Natural fibres like flax and sisal are used as reinforcement; nanosilica particles act as fillers, and epoxy resin as a matrix. The composites were created using the Taguchi L9 orthogonal array and a hand lay-up technique. The mechanical and water retention behaviour of the hybrid composites is based on the following three parameters, each with three different levels: (i) adding different weight ratios of nanofiller (1.5, 3, and 4.5 wt%), (ii) weight ratio of reinforcements (20, 30, and 40 wt%), and (iii) duration of NaOCl conditions (2, 4, and 6 hours). Mechanical possessions like tension, bending, and impact were tested as per the ASTM standard. The tested composites show that 30 wt% reinforcement, 3 wt% nanosilica, and 4 hours of alkaline processing provide the best materials and aquatic preoccupation belongings. When compared to nanofiller composites, nanoparticle-filled composites have 17% evolution in tension, 22% upsurge in flexural strength, 13% in impact strength, and 36% increase in impact strength hygroscopic behaviour. Scanning electron microscopes were used to analyze the fractured structure of hybrid composites. Compared to 1.5 and 4.5 wt% of nanofiller, the 3 wt% of filler provides high interfacial adhesion to the hybrid composites. It helps the reinforcement and matrix to contact each other.

Experimental and modeling analysis of p-type Bi0.4Sb1.6Te3 and graphene nanocomposites

The state-of-the-art Bismuth-Telluride (Bi2Te3) based systems are promising thermoelectric materials for efficient thermoelectric applications. In this study, the effect of graphene nanosheets (GNS) integrity on thermoelectric properties of a p-type Bi0.4Sb1.6Te3 alloy has been studied using high-energy ball milling and SPS sintering techniques. The synthesized pristine Bi0.4Sb1.6Te3 and 0.05wt% GNS/Bi0.4Sb1.6Te3 nanocomposites at different addition times of GNS have exhibited a single-phase and artifact-free bulk nanocrystalline Bi0.4Sb1.6Te3 with nanocrystals size of 17 nm. The TEM analysis confirmed the mechanical exfoliation of graphene filler in 5m nanocomposite into a single-layered nanostructure with an interplanar spacing of 0.343 nm. The prominent Raman features of the monolayered graphene sheet have appeared in the synthesized 5m-GNS/Bi0.4Sb1.6Te3 nanocomposite. This highlighted the crucial rule of graphene addition time on its structure and morphology of the synthesized nanocomposites. The ZT profile of 5m nanocomposite reached 0.801 at 348 K till 398 K. This resulted in 65% of improvements to the pristine Bi0.4Sb1.6Te3 pellet at 323 K. The obtained results were used to simulate a thermoelectric (TE) device module using ANSYS Workbench. The GNS nanocomposites have shown an ultrahigh output power of 95.57 W compared to 89.96 W for the pristine module at ΔT of 150 °C. The GNS addition has increased the output power of pristine Bi0.4Sb1.6Te3 by 7%, leading to comparable TE performance to other simulated Bi2Te3 systems.

Structural, morphological, optical, and dielectric properties of PVA‐PVP filled with zinc oxide aluminum‐graphene oxide composite for promising applications

AbstractPolymer nanocomposites of poly (vinyl alcohol) (PVA), poly (vinyl pyrrolidone) (PVP) filled with various concentration of nanocomposite (Zn0.97Al0.03O: 1 wt% GO)x; x = 1, 3, 5, and 7 wt% were prepared by solution mixing and then cast into films. X‐ray combined with energy dispersive spectroscopy (EDS) data elucidated the successful preparation of pure PVA/PVP and filled films. The identifiable diffraction lines are ascribable to the presence of filler (Zn0.97Al0.03O: 1 wt% GO) that further established by the data of EDS as well as selected area electron diffraction pattern (SAED) achieved by high‐resolution transmission electron microscopy (HRTEM) measurement. The optical band gap (Eg) of composite shows a significant decrement from 5.2 to 4.7 eV as the nanocomposite fillers were varied from 0 to 7 wt%. In addition, the refractive index (n), optical dielectric loss (ε2), and optical conductivity (σopt) were investigated. The PVA/PVP filled with merely 1 wt% of the particle has an extremely high dielectric permittivity and conductivity.