Stable colloidal dispersions of nanostructured semifluorinated acrylic particles with an unfluorinated core and an outer layer consisting of copolymers of the highly hydrophobic and lipophobic heptadecafluorodecyl methacrylate (FMA) were successfully synthesized with the assistance of three different cyclodextrins as phase-transfer catalysts: beta-cyclodextrin (beta-CD), hydroxypropyl beta-cyclodextrin (HpCD), and methyl beta-cyclodextrin (MeCD). While all the cyclodextrins form a stable inclusion complex (IC) with FMA, only the ICs with the more hydrophilic HpCD and MeCD are soluble in water. Nevertheless, incorporation of FMA in the particle shell copolymer could be achieved also when using beta-CD. On the other hand, the morphology of the nanostructured particles was characterized by a ‘‘patchy’’ fluorinated shell dependent on the cyclodextrin used, the best results being obtained with MeCD. A monomer-starved semicontinuous emulsion polymerization procedure was essential to favor the CD-mediated incorporation of FMA into the copolymer structure and to achieve a stable colloidal dispersion even in the presence of small amounts of mixed anionic–nonionic surfactants. The thermal and surface properties of the latex films showed a good correlation with the shell composition and patchy nanostructured morphology of the particles.
Three Different ß-Cyclodextrins Direct the Emulsion Copolymerization of a Highly Fluorinated Methacrylate Towards Distinctive Nanostructured Particle Morphologies
CASTELVETRO, VALTER;BIANCHI, SABRINA;
2011-01-01
Abstract
Stable colloidal dispersions of nanostructured semifluorinated acrylic particles with an unfluorinated core and an outer layer consisting of copolymers of the highly hydrophobic and lipophobic heptadecafluorodecyl methacrylate (FMA) were successfully synthesized with the assistance of three different cyclodextrins as phase-transfer catalysts: beta-cyclodextrin (beta-CD), hydroxypropyl beta-cyclodextrin (HpCD), and methyl beta-cyclodextrin (MeCD). While all the cyclodextrins form a stable inclusion complex (IC) with FMA, only the ICs with the more hydrophilic HpCD and MeCD are soluble in water. Nevertheless, incorporation of FMA in the particle shell copolymer could be achieved also when using beta-CD. On the other hand, the morphology of the nanostructured particles was characterized by a ‘‘patchy’’ fluorinated shell dependent on the cyclodextrin used, the best results being obtained with MeCD. A monomer-starved semicontinuous emulsion polymerization procedure was essential to favor the CD-mediated incorporation of FMA into the copolymer structure and to achieve a stable colloidal dispersion even in the presence of small amounts of mixed anionic–nonionic surfactants. The thermal and surface properties of the latex films showed a good correlation with the shell composition and patchy nanostructured morphology of the particles.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
