Application of mesoporous silica nanoparticles (MSNs) as antifouling/antibacterial carriers is limited and specifically with a dual synergetic effect. In the present work, MSNs modified with quaternary ammonium salts (QASs) and loaded with the biocide Parmetol S15 were synthesized as functional fillers for antifouling/antibacterial coatings. From the family of the MSNs, MCM-48 was selected as a carrier because of its cubic pore structure, high surface area, and high specific pore volume. The QASs used for the surface modification of MCM-48 were dimethyloctadecyl[3-(trimethoxysilyl)propyl]ammonium chloride and dimethyltetradecyl[3-(triethoxysilyl)propyl]ammonium chloride. The QAS-modified MCM-48 reveals strong covalent bonds between the QAS and the surface of the nanoparticles. The surface functionalization was confirmed by Fourier transform infrared spectroscopy, thermogravimetric analysis, elemental analysis, and ζ-potential measurements. Additional loading of the QAS-modified MCM-48 with a commercially available biocide (Parmetol S15) resulted in a synergetic dual antibacterial/antifouling effect. Either loaded or unloaded QAS-modified MSNs exhibited high antibacterial performance confirming their dual activity. The QAS-modified MCM-48 loaded with the biocide Parmetol S15 killed all exposed bacteria after 3 h of incubation and presented 100% reduction at the antibacterial tests against Gram-negative and Gram-positive bacteria. Furthermore, the QAS-modified MCM-48 without Parmetol S15 presented 77-89% reduction against the exposed Gram-negative bacteria and 78-94% reduction against the exposed Gram-positive bacteria. In addition, the modified MCM-48 was mixed with coating formulations, and its antifouling performance was assessed in a field test trial in northern Red Sea. All synthesized paints presented significant antifouling properties after 5 months of exposure in real seawater conditions, and the dual antifouling effect of the nanoparticles was confirmed.

The performance of solar-thermal conversion systems can be improved by incorporation of nanocarbon-stabilized microencapsulated phase change materials (MPCMs). The geometry of MPCMs in the microcapsules plays an important role for improving their heating efficiency andreliability. Yet few efforts have been made to critically examine the formation mechanism of different geometries and their effect on MPCMs-shell interaction. Herein, through changing the cooling rate of original emulsions, we acquire MPCMs within the nanocarbon microcapsules with a hollow structure of MPCMs (h-MPCMs) or solid PCM core particles (s-MPCMs). X-ray photoelectron spectroscopy and atomic force microscopy reveals that the capsule shell of the hMPCMs are enriched with nanocarbons and have a greater MPCMs-shell interaction compared to s-MPCMs. This results in the h-MPCMs being more stable and having greater heat diffusivity within and above the phase transition range than the s-MPCMs do. The geometry-dependent heating efficiency and system stability may have important and general implications for the fundamental understanding of microencapsulation and wider breadth of heating generating systems.3 Solar-thermal conversion, where solar irradiation is harvested and converted to heat for beneficial usage, has gained renewed interest in the past decade and made it a special asset in energy conversions due to its operational simplicity and high energy conversion efficiency. [1][2][3][4] Microencapsulated phase change materials (MPCMs, 1-100 µm diameter), often considered unique micrometer-scaled composites with a superior performance of latent heat thermal storage as compared with bulk PCMs, are currently emerging as positive additives/dopants to the solarthermal conversion systems. Nanocarbon-stabilized MPCMs are of particular interest as they combine the advantages of nanocarbons for their outstanding energy conversion/transfer performance, [5][6][7] MPCMs with an accelerated heat storage/release due to a relatively high surfacearea-to-volume ratio [8][9][10][11][12][13] and the PCM-nanocarbon interactions which often fosters an enhanced enthalpy and better crystallinity. 14,15 A new avenue is therefore opening to enhance the heatgenerating efficiency at a output temperature within and even higher than the solid-liquid phasetransition range (PTR). [16][17][18] By constantly storing and retracting latent heat, 19 the MPCMs are expected to maintain the dynamic equilibrium of output temperatures when the surrounding temperature is around the PTR. More attractively, since the liquid PCMs above PTR store a higher accumulative energy (latent heat + sensible heat) but exhibit a much lower specific heat capacity than the PCMs within PTR, 20,21 the temperatures of PCMs and heat-generating structures would increase synchronously. [22][23][24][25][26][27][28] Consequently, a higher energy storage capacity will be achieved; 17 meanwhile, more heat will be emitted from the MPCMs above PTR to eliminate the convective heat dissipation in the heat-gen...

The butyl methacrylate radical polymerization kinetics in the presence of graphene oxide nanoadditive is studied both experimentally and theoretically. The experimental study includes the formation of graphite oxide from the oxidation of graphite and its subsequent transformation to graphene oxide (GO) after ultrasonication and in situ polymerization. Monomer conversion versus time was monitored gravimetrically at various reaction temperatures and initial GO fractions. Formation of GO was verified by X‐ray diffraction spectra and the number and weight average molecular weights of the final polymer were obtained from GPC measurements. A detailed theoretical kinetic model was further developed. The model predictions were found to be in satisfactory agreement with the experimental data. The presence of GO was found to result in reduced initiator efficiency verified theoretically and explained through side reactions of primary radicals. Finally, nanocomposites showed enhanced thermal stability compared to neat PBMA. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017, 55, 1433–1441

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One of the current challenges in maritime antifouling is the development of new nanostructured coatings which can replace the old protection coatings based on tributyltin biocides prohibited by EU and US legislation as ecologically dangerous. In our study, antibacterial/ antifouling polymer coatings containing innovative dual functionalized nanocapsules demonstrate high antifouling activity in various tests. Capsules are MCM-48 SiO 2 nanoparticles loaded with eco-friendly 4,5dichloro-2-octyl-4-isothiazolin-3-one (DCOIT) antifouling agent and decorated with dimethyloctadecyl [3-(trimethoxysilyl) propyl] ammonium chloride or dimethyltetradecyl [3-(triethoxysilyl) propyl] ammonium chloride (quaternary ammonium salts, QASs) also possessing antifouling activity. Cross section images of the coatings demonstrated the absence of the capsule aggregates in the coatings with slight increase of the surface roughness. The formulated coatings revealed excellent antibacterial performance against E. coli and Staphylococcus aureus according to ISO 22196:2011 protocol. This antifouling activity was also confirmed by immersion of the coated polyvinyl chloride (PVC) panels at a depth of 8−9 m in the sea (Eilat, Israel). Biofouling coverage of 6.9% was observed for nanocapsulesloaded coatings (5 wt % concentration of nanocapsules) compared to the 49% of the coverage for nonmodified coating after 6 months of immersion. The nanocapsules-loaded coatings with dual antifouling functionality demonstrated antifouling activity even after complete release of encapsulated DCOIT because of chemically attached QAS groups on the nanoparticles surface. Moreover, active antifouling materials presented in nanocapsules do not demonstrate any toxicity to the brine shrimps Artemia salina, which are widely used in the food industry.