Nanomaterials

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17 pages, 9936 KiB

Open AccessArticle

Size-Dependent Thresholds in CuO Nanowires: Investigation of Growth from Microstructured Thin Films for Gas Sensing

by Christian Maier, Verena Leitgeb, Larissa Egger and Anton Köck

Nanomaterials 2024, 14(14), 1207; https://doi.org/10.3390/nano14141207 - 16 Jul 2024

Cited by 2 | Viewed by 853

Abstract

An experimental characterization of cupric oxide nanowire (CuO NW) growth from thermally oxidized, microstructured Cu thin films is performed. We have systematically studied the influence of the thickness and dimension of Cu layers on the synthesis of CuO NW. The objective was to [...] Read more.

An experimental characterization of cupric oxide nanowire (CuO NW) growth from thermally oxidized, microstructured Cu thin films is performed. We have systematically studied the influence of the thickness and dimension of Cu layers on the synthesis of CuO NW. The objective was to determine the optimum Cu geometries for increased CuO NWs growth to bridge the gap between adjacent Cu structures directly on the chip for gas sensing applications. Thresholds for CuO-NW growth regarding film thickness and lateral dimensions are identified based on SEM images. For a film thickness of 560 nm, NWs with lengths > 500 nm start to grow from the edges of Cu structures with an area ≥ 4 µm². NWs growing from the upper surface were observed for an area ≥ 16 µm². NW growth between adjacent thermally oxidized thin films was analyzed. The study provides information on the most relevant parameters of CuO NWs growth, which is mandatory for integrating CuO NWs as gas sensor components directly on microchips. Based on this result, the gap size of the structure was varied to find the optimum value of 3 µm. Full article

(This article belongs to the Special Issue Functional Nanocomposites: From Strategic Design to Applications)

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14 pages, 6554 KiB

Open AccessArticle

Wrinkled TiNAgNW Nanocomposites for High-Performance Flexible Electrodes on TEMPO-Oxidized Nanocellulose

by Loïk Gence, Franck Quero, Miguel Escalona, Robert Wheatley, Birger Seifert, Donovan Diaz-Droguett, María José Retamal, Sascha Wallentowitz, Ulrich Georg Volkmann and Heman Bhuyan

Nanomaterials 2024, 14(14), 1178; https://doi.org/10.3390/nano14141178 - 10 Jul 2024

Viewed by 843

Abstract

In this study, we present a novel method for fabricating semi-transparent electrodes by combining silver nanowires (AgNW) with titanium nitride (TiN) layers, resulting in conductive nanocomposite coatings with exceptional electromechanical properties. These nanocomposites were deposited on cellulose nanopaper (CNP) using a plasma-enhanced pulsed [...] Read more.

In this study, we present a novel method for fabricating semi-transparent electrodes by combining silver nanowires (AgNW) with titanium nitride (TiN) layers, resulting in conductive nanocomposite coatings with exceptional electromechanical properties. These nanocomposites were deposited on cellulose nanopaper (CNP) using a plasma-enhanced pulsed laser deposition (PE-PLD) technique at low temperatures (below 200 °C). Repetitive bending tests demonstrate that incorporating AgNW into TiN coatings significantly enhances the microstructure, increasing the electrode’s electromechanical robustness by up to four orders of magnitude compared to commercial PET/ITO substrates. Furthermore, the optical and electrical conductivities can be optimized by adjusting the AgNW network density and TiN synthesis temperature. Our results also indicate that the nanocomposite electrodes exhibit improved stability in air and superior adhesion compared to bare AgNW coatings. Full article

(This article belongs to the Special Issue Functional Nanocomposites: From Strategic Design to Applications)

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16 pages, 1191 KiB

Open AccessArticle

Nanoparticle-Modified 3D-Printed Denture Base Resins: Influence of Denture Cleansers on the Color Stability and Surface Roughness In Vitro

by Mohammed M. Gad, Abdulrahman Khattar, Doha M. Alramadan, Zainab H. Al Dawood, Sujood S. Al Shehab, Rabab H. Al Zaher, Layal Osama Alzain, Soban Q. Khan and Mohamed Y. Abdelfattah

Nanomaterials 2024, 14(10), 891; https://doi.org/10.3390/nano14100891 - 20 May 2024

Cited by 2 | Viewed by 1422

Abstract

This study aimed to evaluate the influence of denture cleansers on the color, stability, and surface roughness of three-dimensional (3D)-printed denture base resins modified with zirconium dioxide nanoparticles (nano-ZrO₂). A total of 440 specimens were fabricated using one heat-polymerized resin, and [...] Read more.

This study aimed to evaluate the influence of denture cleansers on the color, stability, and surface roughness of three-dimensional (3D)-printed denture base resins modified with zirconium dioxide nanoparticles (nano-ZrO₂). A total of 440 specimens were fabricated using one heat-polymerized resin, and two 3D-printed resins (NextDent and ASIGA). According to the nano-ZrO₂ content, the specimens for each resin were divided into five groups (0%, 0.5%wt, 1%wt, 3%wt, and 5%wt). Each concentration was divided into four subgroups (n = 10) based on the immersion solution (distilled water, sodium hypochlorite, Corega, and Fittydent) and immersion duration (360 and 720 days). The color changes (∆E₀₀) and surface roughness (Ra, µm) of each specimen were measured at different time intervals (base line, 360 days, 720 days) using a spectrophotometer and a non-contact profilometer, respectively. The results were statistically analyzed using ANOVA and a post hoc Tukey’s test (α = 0.05). Sodium hypochlorite showed the highest significant color change of all the denture base resins (p < 0.001). The average value of ΔE₀₀ for sodium hypochlorite was significantly higher than the values for the other solutions (Fittydent, Corega, and water) (p < 0.001). Color stability was significantly affected by immersion time for all types of solutions except Corega (p < 0.001). All of the tested immersion solutions (distilled water, sodium hypochlorite, Corega, and Fittydent) showed a significant increase in the surface roughness of all the denture base resins (p < 0.05). Surface roughness was substantially increased by immersion time for all types of solution except Fittydent (p < 0.001). Denture cleansers can result in substantial color change and affect the surface roughness of unmodified and nanoparticle-modified denture base resins. Therefore, the selection of denture cleanser and appropriate types of material is critical for denture longevity. Full article

(This article belongs to the Special Issue Functional Nanocomposites: From Strategic Design to Applications)

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14 pages, 989 KiB

Open AccessArticle

Impact of Nanoparticle Addition on the Surface and Color Properties of Three-Dimensional (3D) Printed Polymer-Based Provisional Restorations

by Maram A. AlGhamdi, Fatimah M. Alatiyyah, Rawan F. Almedarham, Zainab H. Al Dawood, Farah Y. Alshaikhnasser, Shaymaa Y. Alboryh, Soban Q. Khan, Reem Abualsaud and Mohammed M. Gad

Nanomaterials 2024, 14(8), 665; https://doi.org/10.3390/nano14080665 - 11 Apr 2024

Cited by 2 | Viewed by 1182

Abstract

This study aimed to evaluate and compare the impact of additives such as ZrO₂ and SiO₂ nanoparticles (ZrO₂NP or SiO₂NP) on the hardness, surface roughness, and color stability of 3D printed provisional restorations. Two hundred samples in [...] Read more.

This study aimed to evaluate and compare the impact of additives such as ZrO₂ and SiO₂ nanoparticles (ZrO₂NP or SiO₂NP) on the hardness, surface roughness, and color stability of 3D printed provisional restorations. Two hundred samples in total were printed using 3D printed resins (ASIGA, and NextDent). Each resin was modified with ZrO₂NPs or SiO₂NPs in two different concentrations (0.5 wt% and 1 wt%), while one group was kept unmodified (n = 10). Disc-shaped (15 × 2.5 mm) samples were designed and printed in accordance with the manufacturer’s recommendation. Printed discs were evaluated for color changes through parameters CIELAB 2000 system (ΔE₀₀), hardness using Vickers hardness test, and surface roughness (Ra) using a noncontact profilometer. After calculating the means and standard deviations, a three-way ANOVA and Tukey post hoc test were performed at α = 0.05. The addition of ZrO₂NPs or SiO₂NPs to ASIGA and NextDent resins significantly increased the hardness at a given level of concentration (0.5% or 1%) in comparison with pure (p < 0.001), with no significant difference between the two modified groups per resin type (p > 0.05). The highest hardness value was detected in 1% ZrO₂NPs with 29.67 ± 2.3. The addition of ZrO₂NPs or SiO₂NPs had no effect on the Ra (p > 0.05), with 1% ZrO₂NPs showing the highest value 0.36 ± 0.04 µm with NextDent resin. ZrO₂NPs induced higher color changes (∆E₀₀), ranging from 4.1 to 5.8, while SiO₂NPs showed lower values, ranging from 1.01 to 1.85, and the highest mean ∆E₀₀ was observed in the 1% ZrO₂NPs group and NextDent resin. The incorporation of ZrO₂NPs and SiO₂NPs in 3D printed provisional resins increased the hardness without affecting the surface roughness. The optical parameters were significantly affected by ZrO₂NPs and less adversely affected by SiO₂NPs. Consequently, care must be taken to choose a concentration that will improve the materials’ mechanical performance without detracting from their esthetic value. Full article

(This article belongs to the Special Issue Functional Nanocomposites: From Strategic Design to Applications)

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19 pages, 6692 KiB

Open AccessArticle

Comparative Evaluation of TiO₂ Nanoparticle Addition and Postcuring Time on the Flexural Properties and Hardness of Additively Fabricated Denture Base Resins

by Maram A. AlGhamdi, Shaimaa M. Fouda, Noha Taymour, Sultan Akhtar, Soban Q. Khan, Mohamed S. Ali, Ahmed M. Elakel, Essam A. Nassar and Mohammed M. Gad

Nanomaterials 2023, 13(23), 3061; https://doi.org/10.3390/nano13233061 - 30 Nov 2023

Cited by 5 | Viewed by 1632

Abstract

Three-dimensionally (3D)-printed fabricated denture bases have shown inferior strength to conventional and subtractively fabricated ones. Several factors could significantly improve the strength of 3D-printed denture base resin, including the addition of nanoparticles and post-curing factors. This study evaluated the effect of TiO₂ [...] Read more.

Three-dimensionally (3D)-printed fabricated denture bases have shown inferior strength to conventional and subtractively fabricated ones. Several factors could significantly improve the strength of 3D-printed denture base resin, including the addition of nanoparticles and post-curing factors. This study evaluated the effect of TiO₂ nanoparticle (TNP) addition and the post-curing time (PCT) on the flexural properties and hardness of three-dimensionally (3D)-printed denture base resins. A total of 360 specimens were fabricated, with 180 specimens from each type of resin. For evaluating the flexural properties, bar-shaped specimens measuring 64 × 10 × 3.3 mm were used, while, for the hardness testing, disc-shaped specimens measuring 15 × 2 mm were employed. The two 3D-printed resins utilized in this study were Asiga (DentaBASE) and NextDent (Vertex Dental B.V). Each resin was modified by adding TNPs at 1% and 2% concentrations, forming two groups and an additional unmodified group. Each group was divided into three subgroups according to the PCT (15, 60, and 90 min). All the specimens were subjected to artificial aging (5000 cycles), followed by testing of the flexural strength and elastic modulus using a universal testing machine, and the hardness using the Vickers hardness test. A three-way ANOVA was used for the data analysis, and a post hoc Tukey’s test was used for the pairwise comparisons (α = 0.05). Scanning electron microscopy (SEM) was used for the fracture surface analysis. The addition of the TNPs increased the flexural strength in comparison to the unmodified groups (p < 0.001), while there was no significant difference in the elastic modulus and hardness with the 1% TNP concentration. Among the TNP groups, the 2% TNP concentration significantly decreased the elastic modulus and hardness (p < 0.001). The SEM showed a homogenous distribution of the TNPs, and the more irregular fracture surface displayed ductile fractures. The PCT significantly increased the flexural strength, elastic modulus, and hardness (p < 0.001), and this increase was time-dependent. The three-way ANOVA results revealed a significant difference between the material types, TNP concentrations, and PCT interactions (p < 0.001). Both concentrations of the TNPs increased the flexural strength, while the 2% TNP concentration decreased the elastic modulus and hardness of the 3D-printed nanocomposites. The flexural strength and hardness increased as the PCT increased. The material type, TNP concentration, and PCT are important factors that affect the strength of 3D-printed nanocomposites and could improve their mechanical performance. Full article

(This article belongs to the Special Issue Functional Nanocomposites: From Strategic Design to Applications)

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24 pages, 5890 KiB

Open AccessEditor’s ChoiceArticle

Self-Healing Iron Oxide Polyelectrolyte Nanocomposites: Influence of Particle Agglomeration and Water on Mechanical Properties

by Bastian Oberhausen, Ajda Plohl, Bart-Jan Niebuur, Stefan Diebels, Anne Jung, Tobias Kraus and Guido Kickelbick

Nanomaterials 2023, 13(23), 2983; https://doi.org/10.3390/nano13232983 - 21 Nov 2023

Cited by 2 | Viewed by 1585

Abstract

Self-healing nanocomposites can be generated by organic functionalization of inorganic nanoparticles and complementary functionalization of the polymer matrix, allowing reversible interactions between the two components. Here, we report on self-healing nanocomposites based on ionic interactions between anionic copolymers consisting of di(ethylene glycol) methyl [...] Read more.

Self-healing nanocomposites can be generated by organic functionalization of inorganic nanoparticles and complementary functionalization of the polymer matrix, allowing reversible interactions between the two components. Here, we report on self-healing nanocomposites based on ionic interactions between anionic copolymers consisting of di(ethylene glycol) methyl ether methacrylate, sodium 4-(methacryloyloxy)butan-1-sulfonate, and cationically functionalized iron oxide nanoparticles. The materials exhibited hygroscopic behavior. At water contents < 6%, the shear modulus was reduced by up to 90%. The nanoparticle concentration was identified as a second factor strongly influencing the mechanical properties of the materials. Backscattered scanning electron microscopy and small-angle X-ray scattering measurements showed the formation of agglomerates in the size range of 100 nm to a few µm in diameter, independent of concentration, resulting in the disordering of the semi-crystalline ionic polymer blocks. These effects resulted in an increase in the shear modulus of the composite from 3.7 MPa to 5.6 MPa, 6.3 Mpa, and 7.5 MPa for 2, 10, and 20 wt% particles, respectively. Temperature-induced self-healing was possible for all composites investigated. However, only 36% of the maximum stress could be recovered in systems with a low nanoparticle content, whereas the original properties were largely restored (>85%) at higher particle contents. Full article

(This article belongs to the Special Issue Functional Nanocomposites: From Strategic Design to Applications)

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Review

Jump to: Research

34 pages, 7193 KiB

Open AccessReview

Recent Advances in Research from Nanoparticle to Nano-Assembly: A Review

by Shamili Bandaru, Deepshika Arora, Kalathur Mohan Ganesh, Saurabh Umrao, Sabu Thomas, Seemesh Bhaskar and Sabyasachi Chakrabortty

Nanomaterials 2024, 14(17), 1387; https://doi.org/10.3390/nano14171387 - 26 Aug 2024

Viewed by 1843

Abstract

The careful arrangement of nanomaterials (NMs) holds promise for revolutionizing various fields, from electronics and biosensing to medicine and optics. This review delves into the intricacies of nano-assembly (NA) techniques, focusing on oriented-assembly methodologies and stimuli-dependent approaches. The introduction provides a comprehensive overview [...] Read more.

The careful arrangement of nanomaterials (NMs) holds promise for revolutionizing various fields, from electronics and biosensing to medicine and optics. This review delves into the intricacies of nano-assembly (NA) techniques, focusing on oriented-assembly methodologies and stimuli-dependent approaches. The introduction provides a comprehensive overview of the significance and potential applications of NA, setting the stage for review. The oriented-assembly section elucidates methodologies for the precise alignment and organization of NMs, crucial for achieving desired functionalities. The subsequent section delves into stimuli-dependent techniques, categorizing them into chemical and physical stimuli-based approaches. Chemical stimuli-based self-assembly methods, including solvent, acid–base, biomolecule, metal ion, and gas-induced assembly, are discussed in detail by presenting examples. Additionally, physical stimuli such as light, magnetic fields, electric fields, and temperature are examined for their role in driving self-assembly processes. Looking ahead, the review outlines futuristic scopes and perspectives in NA, highlighting emerging trends and potential breakthroughs. Finally, concluding remarks summarize key findings and underscore the significance of NA in shaping future technologies. This comprehensive review serves as a valuable resource for researchers and practitioners, offering insights into the diverse methodologies and potential applications of NA in interdisciplinary research fields. Full article

(This article belongs to the Special Issue Functional Nanocomposites: From Strategic Design to Applications)

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26 pages, 8570 KiB

Open AccessEditor’s ChoiceReview

Polymeric Nanocomposites of Boron Nitride Nanosheets for Enhanced Directional or Isotropic Thermal Transport Performance

by Buta Singh, Jinchen Han, Mohammed J. Meziani, Li Cao, Subhadra Yerra, Jordan Collins, Simran Dumra and Ya-Ping Sun

Nanomaterials 2024, 14(15), 1259; https://doi.org/10.3390/nano14151259 - 27 Jul 2024

Viewed by 1484

Abstract

Polymeric composites with boron nitride nanosheets (BNNs), which are thermally conductive yet electrically insulating, have been pursued for a variety of technological applications, especially those for thermal management in electronic devices and systems. Highlighted in this review are recent advances in the effort [...] Read more.

Polymeric composites with boron nitride nanosheets (BNNs), which are thermally conductive yet electrically insulating, have been pursued for a variety of technological applications, especially those for thermal management in electronic devices and systems. Highlighted in this review are recent advances in the effort to improve in-plane thermal transport performance in polymer/BNNs composites and also the growing research activities aimed at composites of enhanced cross-plane or isotropic thermal conductivity, for which various filler alignment strategies during composite fabrication have been explored. Also highlighted and discussed are some significant challenges and major opportunities for further advances in the development of thermally conductive composite materials and their mechanistic understandings. Full article

(This article belongs to the Special Issue Functional Nanocomposites: From Strategic Design to Applications)

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