Synthesis of amphiphilic triblock copolymers for the formation of magnesium fluoride (MgF₂) nanoparticles

Abstract

A series of amphiphilic poly(2-hydroxyethyl methacrylate)-b-polydimethylsiloxane-b-poly(2-hydroxyethyl methacrylate) (pHEMA-b-PDMS-b-pHEMA) (A-B-A) triblock copolymers were synthesized from three different carbinol-terminated polydimethylsiloxanes with varying molecular weight. A carbinol-terminated polydimethylsiloxane was modified with 2-bromoisobutyryl bromide to obtain a macroinitiator. The block copolymers were characterized by NMR, GPC, and dynamic light scattering (DLS). Reverse micelles of a copolymer were formed in mixture of benzene/methanol solution which served as nanoreactors for the synthesis of magnesium fluoride (MgF 2 ) nanoparticles. The MgF 2 was prepared via chemical precipitation using magnesium chloride and potassium fluoride as reactants. The MgF 2 -triblock copolymer composites were synthesized as a function of MgF 2 -weight ratio (0.5, 5, and 10 wt%) in copolymer. The MgF 2 colloids were dissolved in three organic solvents: methanol, isopropanol, and tetrahydrofuran. The polymer nanoparticles were characterized by DLS, transmission electron microscopy, thermogravimetric analysis, and X-ray diffraction (XRD) analysis. The formation of MgF 2 crystals was observed by XRD. Particle size and particle size distribution showed significant changes in different solvents. The thermal stability of MgF 2 colloids increased as the amount of nanoparticle increased in polymeric matrix.

Sol-Gel Processing of MgF2 Antireflective Coatings

“…Mg(OAc) 2 × 4H 2 O is commonly applied as magnesium source in combination with TFA. The role of heating rates during the film consolidation progress has been investigated [ 20 ]. Polyvinylacetate (PVA) can be used to induce phase separation in the films; using this tailored porosity the optical performance of large-area coatings on glass was optimized [ 21 ], and the annealing temperature was set to 450 °C.…”

The Effects of Various Parameters of the Microwave-Assisted Solvothermal Synthesis on the Specific Surface Area and Catalytic Performance of MgF2 Nanoparticles

“…In particular, nanoscopic magnesium fluoride MgF 2 is frequently applied in antireflective coatings [ 2 , 3 , 4 ], functional ceramics [ 5 ] and catalysis [ 6 , 7 , 8 , 9 ]. Many different synthesis approaches have been developed for the preparation of MgF 2 nanosized particles, such as mechanochemical synthesis [ 10 ], sol–gel processes (TFA [ 11 , 12 ] and fluorolytic [ 13 , 14 , 15 , 16 , 17 , 18 ]), the precipitation method [ 19 , 20 , 21 , 22 , 23 ], reversed micelle synthesis [ 24 , 25 ] and hydro(solvo)thermal synthesis [ 26 , 27 , 28 , 29 , 30 ]. In this last approach, the use of non-metal alkoxides precursors together with the microwave-assisted solvothermal method combines the advantages of rapid heating and the pressurized solvothermal process.…”

High yield synthesis and optical properties of MgF2nanowires with high aspect ratios

“…10 Among uorides and especially the alkaline earth uorides, [11][12][13] nanoscale magnesium uoride (MgF 2 ) is one of the least examined materials. 14,15 Metal uoride nanomaterials are of great interest because of their potential applications in optoelectronics, optics, biological labelling, catalysis elds, and so on. [16][17][18][19] MgF 2 is one of the most interesting materials because of its low refractive index, low chemical reactivity even at elevated temperatures, high thermal stability, high corrosion resistance and signicant hardness.…”