Low-fluorinated homopolymer from heterogeneous ATRP of 2,2,2-trifluoroethyl methacrylate mediated by copper complex with nitrogen-based ligand

A facile approach for preparing tadpole and barbell-shaped cyclic polymers through combining ATRP and atom transfer radical coupling (ATRC) reactions

A facile strategy was developed to prepare active tadpole-shaped cyclic polystyrene, which was then used to fabricate symmetrical barbell polystyrene.

Fluorinated bottlebrush polymers based on poly(trifluoroethyl methacrylate): synthesis and characterization

Fluorinated bottlebrush polymers thin films showed unique surface properties.

Preparation of superhydrophobic films based on the diblock copolymer P(TFEMA-r-Sty)-b-PCEMA

The diblock copolymer P(TFEMA-r-Sty)-b-PCEMA was synthesized and self-assembled to form spherical micelles. Photo-cross-linking the PCEMA domains of these micelles yielded cross-linked nanoparticles. The cross-linked nanoparticles were used to prepare superhydrophobic films.

Adhesion and friction properties of polymer brushes: fluoro versus nonfluoro polymer brushes at varying thickness

A series of different thicknesses of fluoro poly(2,2,2-trifluoroethyl methacrylate) and its analogous nonfluoro poly(ethyl methacrylate) polymer brushes were prepared via surface-initiated ATRP (SI-ATRP) on Si(111) surfaces. The thiol-yne click reaction was used to immobilize the SI-ATRP initiator with a high surface coverage, in order to achieve denser polymer brushes (grafting density from ~0.1 to 0.8 chains/nm(2)). All polymer brushes were characterized by static water contact angle measurements, infrared absorption reflection spectroscopy, and X-ray photoelectron spectroscopy. Adhesion and friction force measurements were conducted with silica colloidal probe atomic force microscopy (CP-AFM) under ambient and dry (argon) conditions. The fluoro poly(2,2,2-trifluoroethyl methacrylate) polymer showed a decrease in adhesion and friction with increasing thickness. The analogous nonfluoro poly(ethyl methacrylate) polymer brushes showed high adhesion and friction under ambient conditions. Friction coefficients down to 0.0057 (ambient conditions) and 0.0031 (dry argon) were obtained for poly(2,2,2-trifluoroethyl methacrylate) polymer brushes with 140 nm thickness, which are the lowest among these types of polymer brushes.

Synthesis of Fluorinated Amphiphilic Block Copolymers Based on PEGMA, HEMA, and MMA via ATRP and CuAAC Click Chemistry

Synthesis of fluorinated amphiphilic block copolymers via atom transfer radical polymerization (ATRP) and Cu(I) catalyzed Huisgen 1,3-dipolar cycloaddition (CuAAC) was demonstrated. First, a PEGMA and MMA based block copolymer carrying multiple side-chain acetylene moieties on the hydrophobic segment for postfunctionalization was carried out. This involves the synthesis of a series of P(HEMA-co-MMA) random copolymers to be employed as macroinitiators in the controlled synthesis of P(HEMA-co-MMA)-block-PPEGMA block copolymers by using ATRP, followed by a modification step on the hydroxyl side groups of HEMA via Steglich esterification to afford propargyl side-functional polymer, alkyne-P(HEMA-co-MMA)-block-PPEGMA. Finally, click coupling between side-chain acetylene functionalities and 2,3,4,5,6-pentafluorobenzyl azide yielded fluorinated amphiphilic block copolymers. The obtained polymers were structurally characterized by1H-NMR,19F-NMR, FT-IR, and GPC. Their thermal characterizations were performed using DSC and TGA.

Robust superamphiphobic coatings based on silica particles bearing bifunctional random copolymers

Reported herein is the growth of bifunctional random copolymer chains from silica particles through a "grafting from" approach and the use of these copolymer-bearing particles to fabricate superamphiphobic coatings. The silica particles had a diameter of 90 ± 7 nm and were prepared through a modified Stöber process before atom transfer radical polymerization (ATRP) initiators were introduced onto their surfaces. Bifunctional copolymer chains bearing low-surface-free-energy fluorinated units and sol-gel-forming units were then grafted from these silica particles by surface-initiated ATRP. Perfluorooctyl ethyl acrylate (FOEA) and 3-(triisopropyloxy)silylpropyl methacrylate (IPSMA) were respectively used as fluorinated and sol-gel-forming monomers in this reaction. Hydrolyzing the IPSMA units in the presence of an acid catalyst yielded silica particles that were adorned with silanol-bearing copolymer chains. Coatings were prepared by spraying these hydrolyzed silica particles onto glass and cotton substrates. A series of four different copolymer-functionalized silica particles samples bearing copolymers with similar FOEA molar fractions (fF) of ~80% but with different copolymer grafting mass ratios (gm) that ranged between 12.3 wt% and 58.8 wt%, relative to silica, were prepared by varying the polymerization protocols. These copolymer-bearing silica particles with a gm exceeding 34.1 wt% were used to coat glass and cotton substrates, yielding superamphiphobic surfaces. More importantly, these particulate-based coatings were robust and resistant to solvent extraction and NaOH etching thanks to the self-cross-linking of the copolymer chains and their covalent attachment to the substrates.

Superhydrophobic hierarchically assembled films of diblock copolymer hollow nanospheres and nanotubes

Reported are the formation of rough particulate films from cross-linked diblock copolymer vesicles and nanotubes and the wetting properties of the resultant films. The diblock copolymers used were F66M200 and F95A135, where the subscripts denote the repeat unit numbers, whereas M, A, and F denote poly(2-cinnamoyloxyethyl methacrylate), poly(2-cinnamoyloxyethyl acrylate), and poly(2,2,2-trifluoroethyl methacrylate), respectively. The precursory polymers to F66M200 and F95A135 were prepared by atom transfer radical polymerization. In 2,2,2-trifluoroethyl methacrylate (FEMA), a selective solvent for F, vesicles and tubular micelles were prepared from F66M200 and F95A135, respectively. Photo-cross-linking the M and A blocks of these aggregates yielded hollow nanospheres and nanotubes bearing F coronal chains. These particles were dispersed into CH2Cl2/methanol, where CH2Cl2 was a good solvent for both blocks and methanol was a poor solvent for F. Casting CH2Cl2/methanol dispersions of these particles yielded films consisting of hierarchically assembled diblock copolymer nanoparticles. For example, the hollow nanospheres fused into microspheres bearing nanobumps after being cast from CH2Cl2/methanol at methanol volume fractions of 30 and 50%. The roughness of these films increased as the methanol volume fraction increased. The films that were cast at high methanol contents were superhydrophobic, possessing water contact angles of ∼160° and water sliding angles of ∼3°.