Fluorine-containing Block Copolymers Research Articles

Two-dimensional directed lamellar assembly in silicon- and fluorine-containing block copolymer with identical surface energies

A block copolymer (BCP) with specific monomer structures of fluoroacrylate polymers was designed by exploiting the inorganic superhydrophobicity and low glass transition temperature of polydimethylsiloxane (PDMS). With the use of a fluorine-containing block providing a surface tension as low as that of PDMS (19.9 < γ\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\gamma$$\\end{document} < 21.5 mN/m), PDMS-b-poly(2,2,3,3,3-pentafluoropropyl acrylate) (PDMS-b-PPeFPA) copolymer was synthesized to create a volume-symmetric lamellar structure. The compositional randomness of the BCP chains adsorbed onto the substrates provided well-balanced interfacial interactions toward the overlaid PDMS-b-PPeFPA (γ\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\gamma$$\\end{document}PDMS-ads ≈ γ\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\gamma$$\\end{document}PPeFPA-ads). Under this symmetric confinement with simultaneous dual neutral interfaces, lamellar microdomains with a sub-10 nm half-pitch feature size were successfully oriented perpendicular to the interfaces at room temperature. We showed the response of the BCP films to a lateral electric field, demonstrating that the perpendicular lamellae were adaptively aligned along the electric vector within a short treatment period. Furthermore, the PDMS-b-PPeFPA system exhibited a remarkable etch contrast for O2 reactive ion etching, yielding unidirectionally aligned air–inorganic nanoarrays emanating from the perpendicular lamellae between the electrodes. This study reports a system engineering approach for conceiving highly immiscible, silicon- and fluorine-containing BCP whose components exhibit identical surface tensions (γ\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\gamma$$\\end{document}PDMS ≈ γ\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\gamma$$\\end{document}PPeFPA) and for generating perpendicularly oriented lamellar microdomains due to substrate neutrality.

Rapid Self-Assembly and Sequential Infiltration Synthesis of High χ Fluorine-Containing Block Copolymers

We leverage the attractive properties of a high χ–low N BCP, i.e., poly(styrene)-block-poly(2-fluoroethylmethyl acrylate) (PS-b-P2FEMA), and illustrate its utility for next-generation nanomanufacturing. The synthesis, physical characterization, and thin film self-assembly of a series of lamellar and cylindrical PS-b-P2FEMA BCPs are delineated. PS-b-P2FEMA BCPs with total molecular weights ranging from 7 to 22 kg mol–1 were synthesized by using reversible addition–fragmentation chain-transfer (RAFT) polymerization. Temperature-resolved small-angle X-ray scattering (SAXS) measurements revealed a large χ value (0.13 at 150 °C) for PS-b-P2FEMA. Solvothermal vapor annealing of PS-b-P2FEMA films produced highly oriented fingerprint patterns in as short as 60 s. Lamellar period sizes ranged from 25.9 down to 14.2 nm with feature sizes as small as 7 nm observed. We also demonstrate the integration feasibility of PS-b-P2FEMA BCPs through alumina hardmask formation using sequential infiltration synthesis. The highly favorable characteristics of the P2FEMA-based BCPs detailed here provide a versatile material option to the current library of available BCPs for sub-10 nm nanolithography.

Amphiphilic Fluorine-Containing Block Copolymers as Carriers for Hydrophobic PtTFPP for Dissolved Oxygen Sensing, Cell Respiration Monitoring and In Vivo Hypoxia Imaging with High Quantum Efficiency and Long Lifetime.

New amphiphilic star or multi-arm block copolymers with different structures were synthesized for enabling the use of hydrophobic oxygen probe of platinum (II)-tetrakis (pentafluorophenyl) porphyrin (PtTFPP) for bioanalysis. The amphiphilic star polymers were prepared through the Atom Transfer Radical Polymerization (ATRP) method by using hydrophilic 4-arm polyethylene glycol (4-arm-PEG) as an initiator. Among the five block copolymers, P1 series (P1a, P1b, and P1c) and P3 possess fluorine-containing moieties to improve the oxygen sensitivity with its excellent capacity to dissolve and carry oxygen. A polymer P2 without fluorine units was also synthesized for comparison. The structure-property relationship was investigated. Under nitrogen atmosphere, high quantum efficiency of PtTFPP in fluorine-containing micelles could reach to 22% and long lifetime could reach to 76 μs. One kind of representative PtTFPP-containing micelles was used to detect the respiration of Escherichia coli (E. coli) JM109 and macrophage cell J774A.1 by a high throughput plate reader. In vivo hypoxic imaging of tumor-bearing mice was also achieved successfully. This study demonstrated that using well-designed fluoropolymers to load PtTFPP could achieve high oxygen sensing properties, and long lifetime, showing the great capability for further in vivo sensing and imaging.

Poly(Pentafluorophenyl Methacrylate)-Based Nano-Objects Developed by Photo-PISA as Scaffolds for Post-Polymerization Functionalization.

The preparation of a functional fluorine-containing block copolymer using reversible addition-fragmentation chain-transfer dispersion polymerization in DMSO as a "platform/scaffold" is explored. The nanostructures, comprised of poly(ethyleneglycol)-b-poly(pentafluorophenyl methacrylate) or PEG-b-P(PFMA), are formulated via photo-initiated polymerization-induced self-assembly (PISA) followed by post-polymerization modification using different primary amines. A combination of light scattering and microscopy techniques are used to characterize the resulting morphologies. It is found that upon varying the degree of polymerization of the core-forming block of PFMA, only uniform spheres (with textured surfaces) are obtained. These nanostructures are subsequently modified by cross-linking using a non-responsive and a redox-responsive diamine, thus imparting stability to the particles in water. In response to intracellular glutathione (GSH) concentration, destabilization of the micelles occurs as evidenced by dynamic light scattering. The well-defined size, inherent reactivity of the nanoparticles toward nucleophiles, and GSH-responsiveness of the nanospheres make them ideal scaffolds for drug delivery to intracellular compartments with reductive environments.

Precise Synthesis of Fluorine-containing Block Copolymers via RAFT

Precise Synthesis of Fluorine-containing Block Copolymers via RAFT

含フッ素セグメントをもつブロックコポリマーの精密合成および水/有機層間を往復可能な高分子ミセルの創製

含フッ素セグメントをもつブロックコポリマーの精密合成および水/有機層間を往復可能な高分子ミセルの創製

Flow Microreactor Synthesis of Fluorine-Containing Block Copolymers

Living anionic polymerization of perfluoroalkyl methacrylates initiated by 1,1-diphenylhexyllithium was conducted without adding lithium chloride in an integrated flow microreactor system. The high degree of polydispersity index (PID) control was achieved at 0°C (2-(nonafluorobutyl)ethyl and 2-(tridecafluorohexyl)ethyl methacrylates) or −40°C (2,2,2-trifluoroethyl methacrylate). The subsequent reaction of a reactive polymer chain end with alkyl methacrylates or tert-butyl acrylate led to the formation of fluorine-containing block copolymers with narrow PDI.

Formation of Breath Figure Arrays in Methanol Vapor Assisted by Surface Active Agents

Breath figure (BF) process is a promising technique for fabricating honeycomb polymer films. It is usually conducted in water vapor. While, in organic vapors only unique polymer can be used to prepare BF arrays as reported in our previous article (Breath Figure in Nonaqueous Vapor. Soft Matter, 2013, 506-514), although new structure features are induced in the film. In this paper, a universal modified BF processing is devised for preparing porous films in methanol vapor with conventional polymers, by adding a small amount of surface active agent into the casting solution, such as siloxane- and fluorine-containing block copolymers. The pores in the PS films prepared with this method are of cylindrical shape with large depth-diameter aspect ratio, and the diameter and depth of pores can be well controlled by the experiment conditions. Based on these results, the formation mechanism of honeycomb structure in methanol vapor is discussed.

Dual Mode Patterning of Fluorine-Containing Block Copolymers through Combined Top-down and Bottom-up Lithography

Integrated nanopatterns were successfully obtained from a combination of high lateral ordering of newly designed self-assembling fluorine-containing block copolymers and degradation of the fluorine-containing polymer nanodomains in e-beam irradiated areas. The fluorine-containing block copolymers of poly(styrene-block-2,2,2-trifluoroethyl methacrylate) (PS-b-PTFEMA) and poly[styrene-block-(methyl methacrylate-co-2,2,2-trifluoroethyl methacrylate)] (PS-b-(PMMA-co-PTFEMA)), which are capable of both top-down and bottom-up lithography, were developed. The reported block copolymers were synthesized by either anionic polymerization or atom transfer radical polymerization (ATRP). Characterization of bulk and thin films were carried out using differential scanning calorimetry (DSC), transmission electron microscopy (TEM), and small-angle X-ray scattering (SAXS), and these studies revealed the formation of highly ordered self-assembled structures. Lateral ordering of arrays of PS dots was observed in the thin film of PS-b-PTFEMS, in which PS was the minor block, and the thin film of PS-b-(PMMA-co-PTFEMA), in which PS was the major block. These thin films were subjected to conventional lithographic processing using e-beam and deep-UV radiation to create integrated patterns such as “dots in lines”.

Fluorine-containing block copolymer particles with surface and internal hierarchical microphase separation structures

Polymeric particles with diverse surface and internal hierarchical nanostructures were prepared by the dynamic self-assembly of a fluorine-containing diblock copolymer, poly(tert-butylacrylate)-b-poly(2-[(perfluorononenyl) oxy] ethyl methacrylate) (PtBA-b-PFNEMA) in THF/water mixtures. The surface patterns and internal structures both originated from the microphase separation of PtBA-b-PFNEMA and could be tuned by the preparation conditions. Besides, the interface limitations and geometric confinement of the particles' morphology resulted in the formation of different phase separation structures on the surface and inside the particles. By tuning the water content and preparation temperature, almost parallel cylindrical domains, twisted interconnected cylindrical domains, or spherical domains were obtained on the surface of the particles. Meanwhile, the internal structures of the particles transformed from inner stacked lamella with outer onion-like structures, inner disordered with outer onion-like structures, to bicontinuous structures as the chain mobility and incompatibility of the two blocks could be controlled by the preparation condition. Therefore, the integration of diverse cylindrical surface structures and bicontinuous or onion-like inner structures into hierarchical nanoparticles was achieved.

Association behavior of fluorine-containing and non-fluorine-containing methacrylate-based amphiphilic diblock copolymer in aqueous media.

Fluorine-containing amphiphilic block copolymers, poly(sodium methacrylate)-block-poly(nonafluorohexyl methacrylate) (NaMAm-b-NFHMAn) (m:n = 61:12, 72:33, 64:57), and the corresponding non-fluorine-containing amphiphilic block copolymer, poly(sodium methacrylate)-block-poly(hexyl methacrylate) (NaMAm-b-HMAn) (m:n = 64:10, 69:37, 67:50), were synthesized. Both polyNaMA-b-polyNFHMA and polyNaMA-b-polyHMA formed micelles above critical micelle concentrations, (cmc's), around 3 x 10(-5) to 1 x 10(-4) mol/L, while neither polymer decreased surface tension of aqueous solutions. The size and shape of the micelles were examined by dynamic light scattering, small-angle neutron scattering, and small-angle X-ray scattering. PolyNaMA-b-polyHMA appeared to form only spherical micelles, while polyNaMA-b-polyNFHMA with a long NFHMA segment formed both spherical and rodlike micelles. The micelles of fluorine-containing block copolymers were obviously larger than those of non-fluorine-containing block copolymers with the same chain length and the same hydrophilic/hydrophobic chain ratio. The fluorine-containing block copolymer selectively solubilized fluorinated dye into the water phase when a mixture of decafluorobiphenyl and 2,6-dimethylnaphthalene was added to the micelle solution.

Fluorinated Amphiphilic Vinyl Ether Block Copolymers: Synthesis and Characteristics of Their Micelles in Water

Fluorine-containing amphiphilic block copolymers, poly(2-hydroxyethyl vinyl ether)-block-poly(2-(2,2,2-trifluoroethoxy)ethyl vinyl ether)) (poly(HOVE-b-TFEOVE) (m = 78, n = 23)), poly(2-hydroxyethyl vinyl ether)-block-poly(2-(2,2,3,3,3-pentafluoropropoxy)ethyl vinyl ether) (poly(HOVE-b-PFPOVE) (m = 74, n = 22)), and poly(2-hydroxyethyl vinyl ether)-block-poly(2-(2,2,3,3,4,4,4-heptafluorobutoxy)ethyl vinyl ether) (poly(HOVE-b-HFBOVE) (m = 79, n = 19)) were synthesized along with the non-fluorine-containing amphiphilic block copolymer, poly(2-hydroxyethyl vinyl ether)-block-poly(n-butyl vinyl ether) (poly(HOVE-b-NBVE) (m = 70, n = 22)), where m and n are polymerization degrees of hydrophilic segment and hydrophobic segment, respectively. These fluorine-containing block copolymers considerably reduced the surface tension of the aqueous solutions, indicating the high surface activity of the block copolymers. They formed core−shell rodlike and/or core−shell spherical micelles in aqueous solutions, which were e...

Water-Soluble Fluorine-Containing Amphiphilic Block Copolymer: Synthesis and Aggregation Behavior in Aqueous Solution

Fluorine-containing block copolymers consisting of poly(2-hydroxyethyl vinyl ether) (polyHOVE) and poly(2-(2,2,2-trifluoroethoxy)ethyl vinyl ether) (polyTFEOVE) with different degrees of polymerization were synthesized by sequential cationic polymerization of 2-(acetoxyethyl) vinyl ether (AcOVE) and TFEOVE, followed by hydrolysis of the acetyl protecting group. Poly(HOVE-b-TFEOVE) (m:n = 32:10, 28:13, 34:20, 34:31, where m and n represent the degree of polymerization of HOVE and TFEOVE segments, respectively) showed amphiphilic characters and was soluble in water and nonpolar solvents such as toluene. The surface tension of the polymer aqueous solution decreased to ca. 30 mN/m at polymer concentrations around 1 × 10-4 mol/L. SAXS measurement of the aqueous polymer solution revealed that the polymers formed core−shelled spherical micelles at concentrations of 1.0 wt %. Poly(HOVE-b-TFEOVE) (m:n = 34:31) aqueous solution solubilized more hexafluorobenzene than the nonfluorinated amphiphilic block polymer, poly(HOVE-b-n-butyl vinyl ether) did, which was confirmed by measurement of the UV absorption of each solution.

Synthesis of fluorine-containing block copolymers via ATRP 2. Synthesis and characterization of semifluorinated di- and triblock copolymers

A series of semifluorinated fluorocarbon/hydrocarbon di- and triblock copolymers were prepared by atom transfer radical polymerization (ATRP). The mono- and difunctional macroinitiators, which were obtained from bulk ATRP of styrene, butyl acrylate and methyl acrylate, initiated solution ATRP of 2-[(perfluorononenyl)oxy]ethyl methacrylate and ethylene glycol mono-methacrylate mono-perfluorooctanoate, respectively. The formation of the block copolymer was confirmed with size exclusion chromatography and 1H NMR spectrum.

Synthesis of fluorine-containing block copolymers via ATRP 1. Synthesis and characterization of PSt-PVDF-PSt triblock copolymers

A technique is described for the synthesis of polystyrene- block-poly(vinylidene fluoride)- block-polystyrene (St-VDF-St) triblock copolymers through a poly(vinylidene fluoride) macroinitiator. The bromine terminated poly(vinylidene fluoride), which was prepared by radical telomerization of vinylidene fluoride with 1,2-dibromotetrafluoroethane, initiated polymerization of styrene in presence of copper(I) bromide and α,α′-bispyridine complexes. It was found that molecular weights increased linearly in styrene conversion and polydispersities were low. The macroinitiator and block copolymers were characterized by g.p.c. and n.m.r.

Surface modification of epoxy resin with fluorine‐containing methacrylic ester copolymers

AbstractTo improve oil and water repellency, fluorine‐containing block copolymers, which were composed of methyl methacrylate (MMA), glycidyl methacrylate (GMA), and 1H, 1H, 2H, 2H‐heptadecafluorodecyl acrylate (PFA), were blended with an epoxy resin. It was expected that a glycidyl group would mesh with the epoxy resin by primary bonding, and the low surface energy fluorocarbon segment would absorb and orient to the exterior to fluorinate the surface. X‐ray photoelectron spectroscopy, contact angle, and peel strength of pressure‐sensitive adhesives for modified epoxy resin surface were determined. The amount of fluorine obtained via angular‐dependent ESCA investigation in the modified resin surfaces increased with the shallowing of the sampling depth. With increasing modifier content, the amount of fluorine in the modified resin surface layer increased, and the critical surface tension of modified resin surfaces and the peel strength of a silicone pressuresensitive adhesive affixed to the modified epoxy resin, decreased. A considerable amount of fluorine in the resin surface modified with GMA‐containing block copolymers remained after Soxhlet extraction, whereas in the surface modified with copolymer without GMA, more fluorine was extracted. It was extracted. It was shown that these copolymers were good surface modifiers to improve oil and water repellency. © 1993 John Wiley &amp; Sons, Inc.

ブロックおよびグラフトコポリマーの合成とその応用に関する研究 ＩＸ 含フッ素ブロック共重合体の界面特性

ブロックおよびグラフトコポリマーの合成とその応用に関する研究 ＩＸ 含フッ素ブロック共重合体の界面特性