Nanocontainer-Based Active Systems: From Self-Healing Coatings to Thermal Energy Storage

We highlight the development of nanocontainer-based active materials started in 2006 at the Max Planck Institute of Colloids and Interfaces under the supervision of Prof. Helmuth Moehwald. The active materials encapsulated in the nanocontainers with controlled shell permeability have been first applied for self-healing coatings with controlled release of the corrosion inhibitor. The nanocontainers have been added to the paint formulation matrix at 5−10 wt % concentration, which resulted in attaining a coating-autonomous selfhealing ability. This research idea has attracted the attention of many scientists around the world (>1500 publications during the last 10 years) and has already been transferred to the commercialization level. The current trend in nanocontainer-based active systems is devoted to the multifunctionality of the capsules which can combine self-healing, antibacterial, thermal, and other functionalities into one host matrix. This article summarizes the previous research done in the area of nanocontainer-based active materials together with future perspectives of capsule-based materials with antifouling or thermoregulating activity

Nanoencapsulation of phase change materials for advanced thermal energy storage systems

A review focusing on phase change materials for thermal energy storage, particularly their nanoencapsulation, and insight into future research possibilities.</p

A rapid synthesis of nanofibrillar cellulose/polystyrene composite via ultrasonic treatment

A new method of the synthesis of nanofibrillar cellulose/polystyrene composite based on ultrasonic treatment of styrene emulsion in cellulose-water solution was elaborated. A new approach does not require additional heating and proposes a significantly faster synthesis (15 min, 45 °C) of the target composite compared to the methods described previously. A comprehensive analysis did not reveal any significant differences between mechanical, physical and biodegradable properties of the composite obtained by ultrasonic method and that one obtained by conventional thermal method, which requires much higher temperature (above 75 °C) and reaction duration (from 3 h)

Generic Delivery of Payload of Nanoparticles Intracellularly via Hybrid Polymer Capsules for Bioimaging Applications

Towards the goal of development of a generic nanomaterial delivery system and delivery of the ‘as prepared’ nanoparticles without ‘further surface modification’ in a generic way, we have fabricated a hybrid polymer capsule as a delivery vehicle in which nanoparticles are loaded within their cavity. To this end, a generic approach to prepare nanomaterials-loaded polyelectrolyte multilayered (PEM) capsules has been reported, where polystyrene sulfonate (PSS)/polyallylamine hydrochloride (PAH) polymer capsules were employed as nano/microreactors to synthesize variety of nanomaterials (metal nanoparticles; lanthanide doped inorganic nanoparticles; gadolinium based nanoparticles, cadmium based nanoparticles; different shapes of nanoparticles; co-loading of two types of nanoparticles) in their hollow cavity. These nanoparticles-loaded capsules were employed to demonstrate generic delivery of payload of nanoparticles intracellularly (HeLa cells), without the need of individual nanoparticle surface modification. Validation of intracellular internalization of nanoparticles-loaded capsules by HeLa cells was ascertained by confocal laser scanning microscopy. The green emission from Tb3+ was observed after internalization of LaF3:Tb3+(5%) nanoparticles-loaded capsules by HeLa cells, which suggests that nanoparticles in hybrid capsules retain their functionality within the cells. In vitro cytotoxicity studies of these nanoparticles-loaded capsules showed less/no cytotoxicity in comparison to blank capsules or untreated cells, thus offering a way of evading direct contact of nanoparticles with cells because of the presence of biocompatible polymeric shell of capsules. The proposed hybrid delivery system can be potentially developed to avoid a series of biological barriers and deliver multiple cargoes (both simultaneous and individual delivery) without the need of individual cargo design/modification

Polymeric Nanocapsule from Silica Nanoparticle@Cross-linked Polymer Nanoparticles via One-Pot Approach

A facile strategy was developed here to prepare cross-linked polymeric nanocapsules (CP nanocapsules) with silica nanoparticles as templates. The silica nanoparticle@cross-linked polymer nanoparticles were prepared by the encapsulation of the silica nanoparticles by the one-pot approach via surface-initiated atom transfer radical polymerization of hydroxyethyl acrylate in the presence ofN,N′-methylenebisacrylamide as a cross-linker from the initiator-modified silica nanoparticles. After the silica nanoparticle templates were etched with hydrofluoric acid, the CP nanocapsules with particle size of about 100 nm were obtained. The strategy developed was confirmed with Fourier transform infrared, thermogravimetric analysis and transmission electron microscopy

Modified Mesoporous Silica Nanoparticles with a Dual Synergetic Antibacterial Effect

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