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A series of amphiphilic poly(2-hydroxyethyl methacrylate)-b-polydimethylsiloxane-b-poly(2-hydroxyethyl methacrylate) (pHEMAb-PDMS-b-pHEMA) (A-B-A) triblock copolymers were synthesized with varying block molecular weights. Control over the polymerization, micellar size and size distribution, dynamic mechanical properties, and film morphology of nine triblock copolymers was investigated as a function of block length. The polymerization resulted in copolymers with polydispersity index below 1.5. The self-assembly behavior of the triblock copolymers was studied in selective solvents for A and B blocks. The micellar diameter was determined by dynamic light scattering and transmission electron microscopy. The film morphologies were investigated by small angle X-ray scattering. Phase separation was observed when the blocks had similar molecular weights (symmetry). However, the ordering of the morphology was disrupted when the blocks lengths were asymmetric. Phase separation was observed by atomic force microscopy when the block molecular weights were symmetric. The viscoelastic properties were examined using dynamic mechanical analysis. The modulus and crosslink density increased with increasing pHEMA content.

Two methods were used to prepare polysiloxanefunctionalized acrylic latexes via emulsion polymerization. Ethyl acrylate and 2-ethylhexyl acrylate were used in both methods as acrylic phase. In the first method, an acrylic core was prepared with addition of a coupling agent, 3-(trimethoxysilyl) propyl methacrylate, after which cyclic siloxane monomer (octamethylcyclotetrasiloxane) was reacted with the coupling agent. In the second method, a silaneterminated polysiloxane (H-PDMS) was reacted with ethylene glycol dimethacrylate, and then copolymerized with ethyl acrylate and 2-ethylhexyl acrylate in a batch emulsion polymerization. Particle size distribution and particle morphology were evaluated by using dynamic light scattering (DLS) and transmission electron microscopy (TEM), respectively. Core-shell morphology was observed in TEM for the first preparation method as proposed. After film formation, surface tension, morphology and dynamic mechanical properties were investigated. Stratification of polysiloxane was examined by Fourier-transform infrared spectroscopy (FT-IR) and energy dispersive X-ray (EDX). Energy dispersive X-ray data indicated that only the second preparation method had higher silicon content at film-air interface than film-substrate interface. In both methods, storage modulus and surface energy of latex films decreased after grafting polysiloxane.

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.

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