Natural Tubule Clay Template Synthesis of Silver Nanorods for Antibacterial Composite Coating

Abstract

Halloysite is naturally available clay mineral with hollow cylindrical geometry and it is available in thousands of tons. Silver nanorods were synthesized inside the lumen of the halloysite by thermal decomposition of the silver acetate, which was loaded into halloysite from an aqueous solution by vacuum cycling. Images of individual ca. 15 nm diameter silver nanorods and nanoparticles were observed with TEM. The presence of silver inside the tubes was also verified with STEM-EDX elemental mapping. Nanorods had crystalline nature with [111] axis oriented ~68° from the halloysite tubule main axis. The composite of silver nanorods encased in clay tubes with the polymer paint was prepared, and the coating antimicrobial activity combined with tensile strength increase was demonstrated. Coating containing up 5% silver loaded halloysite did not change color after light exposure contrary to the sample prepared with loading with unshelled silver nanoparticles. Halloysite tube templates have a potential for scalable manufacturing of ceramic encapsulated metal nanorods for composite materials.

Thin-walled nanoscrolls by multi-step intercalation from tubular halloysite-10 Å and its rearrangement upon peroxide treatment

“…The tubular morphology of halloysite with nano-sized diameter, the corresponding one-dimensional mesoor macroporosity offer various practical applications as catalysts, filling or packing materials, nanocontainers or nano-sized chemical reactors [1][2][3][4][5] and adsorbents [5]. Optimization of surface properties are of importance in the preparation of polymer hybrids [6], functional materials and intelligent surface coatings [7][8][9][10], biomimetric nanoreactor [3,11], as well as catalyst supports [12,13]. With the preparation of halloysite nanocomposites/hybrids novel types of materials with desirable properties can be generated.…”

Pharmaceutical properties of supramolecular assembly of co-loaded cardanol/triazole-halloysite systems

“…Modification of the halloysite tube outer surface via covalent bond formation may open up new applications based upon molecular recognition, such as molecular separation, molecular storage, catalysis, and drug delivery Abdullayev et al, 2011;Lvov et al, 2008;Massaro et al, 2014a,b,c).…”

Selective Functionalization of Halloysite Cavity by Click Reaction: Structured Filler for Enhancing Mechanical Properties of Bionanocomposite Films

“…1,2 All of these features make HNTs suitable for use in catalyst supports, 3−6 water decontamination, 7,8 encapsulation and controlled release of chemically and biologically active compounds with smart functions (antibacterial, 9,10 anticorrosion, 11 and self-healing 12 functionalities), and fillers for polymers. 13−16 HNTs are rather polydisperse in size with external diameters of 50−80 nm, lumens of 10−15 nm, and lengths of about 1000 nm.…”