Eco-Friendly Fumed Nanosilica@Nanodiamond Hybrid Nanoparticles with Dual Sustainable Self-Healing and Barrier Anticorrosive Performances in Epoxy Coating

Fumed nanosilica@nanodiamond attached by APTES [(3-aminopropyl) triethoxysilane], named FSiO2@sND, was examined as an efficient anticorrosive nanohybrid for epoxy coating. Compared with fumed nanosilica (FSiO2), nanodiamond (ND) moderated the hydrophilic nature of FSiO2@sND and offered additional functional groups to the nanohybrid, i.e., carboxylic groups of ND and functional groups of APTES, while retaining the eco-friendly nature of FSiO2 in the hybrid nanoparticle. The hybrid nanoparticle showed pH-sensitive release behavior in which APTES is released considerably in an alkaline medium, acting as an efficient corrosion inhibitor. A thorough electrochemical impedance spectroscopy (EIS) study of scratched coatings in a 3.5% NaCl solution disclosed that FSiO2@sND nanoparticles (at 0.33 wt % loading) conferred significant active/self-healing anticorrosion properties for the epoxy coatings, thanks to the release of APTES and the presence of carboxylic groups of ND taking part in forming a stable protective film on the substrate. Accordingly, epoxy/FSiO2@sND coatings showed a corrosion improvement efficiency of 138% at an optimum immersion time of 5 h, which was higher than the 96% improvement for epoxy/FSiO2 coating. Epoxy/FSiO2@sND intact coating showed much higher low-frequency impedance, i.e., 7.23 Ω·cm2, compared with epoxy/FSiO2 coating, i.e., 5.44 Ω·cm2, and neat epoxy coating, i.e., 5.71 Ω·cm2, after 22 weeks of immersion in salty solution. This result along with a detailed analysis of EIS data for intact coatings suggested that FSiO2@sND brought about strong barrier anticorrosive performance for epoxy coating. Such behavior was attributed to improved dispersion of nanohybrid in the epoxy matrix, enhanced cross-link density of the epoxy matrix, and improved coating/substrate adhesion caused by APTES and the carboxylic groups of ND.

Incorporating Aminated Nanodiamonds to Improve the Mechanical Properties of 3D-Printed Resin-Based Biomedical Appliances

The creation of clinically patient-specific 3D-printed biomedical appliances that can withstand the physical stresses of the complex biological environment is an important objective. To that end, this study aimed to evaluate the efficacy of aminated nanodiamonds (A-NDs) as nanofillers in biological-grade acrylate-based 3D-printed materials. Solution-based mixing was used to incorporate 0.1 wt% purified nanodiamond (NDs) and A-NDs into UV-polymerized poly(methyl methacrylate) (PMMA). The ND and A-ND nanocomposites showed significantly lower water contact angles (p < 0.001) and solubilities (p < 0.05) compared to those of the control. Both nanocomposites showed markedly improved mechanical properties, with the A-ND-containing nanocomposite showing a statistically significant increase in the flexural strength (p < 0.001), elastic modulus (p < 0.01), and impact strength (p < 0.001) compared to the control and ND-containing groups. The Vickers hardness and wear-resistance values of the A-ND-incorporated material were significantly higher (p < 0.001) than those of the control and were comparable to the values observed for the ND-containing group. In addition, trueness analysis was used to verify that 3D-printed orthodontic brackets prepared with the A-ND- and ND-nanocomposites exhibited no significant differences in accuracy. Hence, we conclude that the successful incorporation of 0.1 wt% A-ND in UV-polymerized PMMA resin significantly improves the mechanical properties of the resin for the additive manufacturing of precisive 3D-printed biomedical appliances.

Polymer/nanodiamond composites - a comprehensive review from synthesis and fabrication to properties and applications

Nanodiamond (ND) is an allotrope of carbon nanomaterials which exhibits many outstanding physical, mechanical, thermal, optical and biocompatibility characteristics. Meanwhile, ND particles possess unique spherical shape containing diamond-like structure at the core with graphitic carbon outer shell which intuitively contains many oxygen-containing functional groups at the outer surface. Such superior properties and unique structural morphology of NDs are essentially attractive to develop polymer composites with multifunctional properties. However, despite a long history from the discovery of NDs, which is dated back to the1960s, this nanoparticle has been less explored in the field of polymer (nano)composites compared with other carbon nanomaterials, e.g. carbon nanotube (CNT) and graphene. However, open literature indicates that research works in the field of polymer/ND (PND) composites have gained great momentum in the past half a decade. The present article provides a comprehensive review on recent achievements in ND based polymer composites. This review covers a very broad aspect from the synthesis, purification and functionalization of NDs to dispersion, preparation and fabrication of polymer/ND (PND) composites with a look in their recent applications for both structural and functional basis. Therefore, the review would be useful to pave the way for researchers to take some advancing steps in this respect.

Polydimethylsiloxane/Nanodiamond Composite Sponge for Enhanced Mechanical or Wettability Performance

Polydimethylsiloxane (PDMS) is widely utilized in material science, chemical engineering, and environmental science due to its excellent properties. By utilizing fillers, so-called composite materials can be obtained with enhanced mechanical, wettability, or thermal conductivity performance. Here, we present a simple, cost-effective approach to vary either the mechanical properties (Young's modulus) or surface wettability of bulk PDMS and PDMS sponges simply by adding nanodiamond filler with different surface terminations, either oxidized (oND) or hydrogenated (reduced, rND) nanodiamond. Minuscule amounts of oxidized nanodiamond particles as filler showed to benefit the compressive Young's modulus of composite sponges with up to a 52% increase in its value, while the wettability of composite sponges was unaffected. In contrast, adding reduced nanodiamond particles to PDMS yielded inclined water contact angles on the PDMS/nanodiamond composite sponges. Finally, we show that the PDMS/rND composites are readily utilized as an absorbent for oil/water separation problems. This signifies that the surface termination of the ND particle has a crucial effect on the performance of the composite.

Fabrication of AIE-active amphiphilic fluorescent polymeric nanoparticles through host–guest interaction

Novel polymeric luminescent nanoprobes with aggregation induced emission (AIE) properties were fabricatedviahost–guest interaction between the β-CD pendant copolymers and adamantane-terminated AIE dye.

Supermolecular self assembly of AIE-active nanoprobes: fabrication and bioimaging applications

AIE active luminescent polymeric nanoprobes were fabricated for the first time via formation of supermolecular complexes between an adamantane capped AIE dye and β cyclodextrin.