Preparation and applications of a variety of fluoroalkyl end-capped oligomer/hydroxyapatite composites

A variety of fluoroalkyl end-capped oligomers were applied to the preparation of fluorinated oligomer/hydroxyapatite (HAp) composites (particle size: 38-356 nm), which exhibit a good dispersibility in water and traditional organic solvents. These fluoroalkyl end-capped oligomer/HAp composites were easily prepared by the reactions of disodium hydrogen phosphate and calcium chloride in the presence of self-assembled molecular aggregates formed by fluoroalkyl end-capped oligomers in aqueous solutions. In these fluorinated HAp composites thus obtained, fluoroalkyl end-capped acrylic acid oligomers and 2-methacryloyloxyethanesulfonic acid oligomer/HAp nanocomposites afforded transparent colorless solutions toward water; however, fluoroalkyl end-capped N,N-dimethylacrylamide oligomer and acryloylmorpholine oligomer were found to afford transparent colorless solutions with trace amounts of white-colored HAp precipitants under similar conditions. HAp could be encapsulated more effectively into fluorinated 2-methacryloyloxyethanesulfonic acid oligomeric aggregate cores to afford colloidal stable fluorinated oligomer/HAp composites, compared to that of fluorinated acrylic acid oligomers. These fluorinated oligomer/HAp composites were applied to the surface modification of glass and PVA to exhibit a good oleophobicity imparted by fluorine. HAp formation was newly observed on the modified polyethylene terephthalate film surface treated with fluorinated 2-methacryloyloxyethanesulfonic acid oligomers and acrylic acid oligomer/HAp composites by soaking these films into the simulated body fluid.     

Preparation of fluoroalkyl end-capped oligomers/magnetite nanocomposites possessing a good dispersibility and stability

Fluoroalkyl end-capped vinylphosphonic acid cooligomers-encapsulated magnetite nanocomposites were prepared by the magnetization of aqueous ferric and ferrous ions in the presence of the corresponding fluorinated cooligomers and magnetic nanoparticles under alkaline conditions. These fluorinated cooligomers magnetic composites are nanometer size-controlled very fine particles and have a good dispersibility and stability in water and traditional organic solvents. These fluorinated nanocomposites were also applied to the surface modification of poly(methyl methacrylate) to exhibit a good oleophobicity imparted by fluorine on their surface. Fluoroalkyl end-capped 2-methacryloyloxyethanesulfonic acid oligomer-encapsulated magnetite nanocomposites and fluoroalkyl end-capped 2-acrylamide-2-methylpropanesulfonic acid oligomer-encapsulated magnetite nanocomposites were prepared in good isolated yields by the magnetization of iron chlorides in the presence of the corresponding oligomers and magnetic nanoparticles under similar conditions. Colloidal stability of these fluorinated nanocomposites thus obtained in water was demonstrated to become extremely higher than that of fluorinated vinylphosphonic acid cooligomers/magnetic nanocomposites.     

Preparation and applications of novel fluoroalkyl end-capped 2-acrylamido-2-methylpropanesulfonic acid oligomer/clay nanocomposites

New fluoroalkyl end-capped 2-acrylamido-2-methylpropanesulfonic acid oligomers/clay composites were prepared by reaction of fluoroalkanoyl peroxide with the corresponding monomer in the presence of clay in aqueous solutions. These obtained fluorinated composites were nanometer size-controlled and were found to exhibit a good dispersibility in water and polar organic solvents such as methanol. The contents of clay in these nanocomposites were estimated to be 3～19% by the thermogravimetric analysis measurements. X-ray diffraction spectra showed the successful intercalation of fluorinated oligomers into the interlayer spaces of clay. These fluorinated clay nanocomposites were applied to the surface modification of poly(vinyl alcohol). In addition, these fluorinated nanocomposites were found to interact with methylene blue effectively to afford the fluorinated oligomers/clay/methylene blue nanocomposites.     

Preparation and applications of novel fluoroalkyl end‐capped oligomers/polyimide/silica nanocomposites

Fluoroalkyl end‐capped acrylic acid, N,N‐dimethylacrylamide, N‐(1,1‐dimethyl‐3‐oxobutyl)acrylamide and vinyltrimethoxysilane oligomers reacted with polyamic acid possessing trimethoxysilyl groups under alkaline conditions to yield the corresponding fluoroalkyl end‐capped oligomers/polyamic acid/silica nanocomposites. These isolated fluorinated composite powders were found to afford nanometer size‐controlled fine particles with a good dispersibility and stability in water and traditional organic solvents. We succeeded in preparing new fluoroalkyl end‐capped oligomers/polyimide/silica nanocomposites by the imidization of fluorinated polyamic acid silica nanocomposites through the stepwise heating at 110 and 270°C under air atmosphere conditions. These fluorinated polyimide/silica nanocomposites thus obtained were applied to the surface modification of glass and poly(methyl methacrylate) (PMMA) to exhibit good hydro‐ and oleo‐phobic characteristics imparted by fluoroalkyl groups in the composites on their surface. In addition, the surface morphology of the modified glass treated with these fluorinated nanocomposites were analyzed by using FE‐SEM and DFM. Copyright © 2011 John Wiley & Sons, Ltd.     

Preparation of novel cross-linked fluoroalkyl end-capped adamantane cooligomer/copper nanocomposites

Copper(II) oxide reacted with hydrazine in the presence of fluoroalkyl end-capped oxime-blocked isocyanato cooligomer containing adamantyl segments at 90 °C for 30 min in ethylene glycol, and the deprotecting reaction of the cooligomer in the resulting product at 120 °C for 15 min was found to afford the colloidal red-brown colored cross-linked fluorinated cooligomer/Cu nanocomposites, which were stabilized by fluoroalkyl end-capped cooligomer containing benzotriazole segments. On the other hand, the corresponding cross-linked fluorinated cooligomer possessing no adamantyl segments could not afford the copper nanocomposites under similar conditions. Dynamic light scattering measurements and TEM photography of these cross-linked fluorinated cooligomer/Cu composites showed that these composites are nanometer size-controlled very fine nanoparticles. These fluorinated Cu nanocomposites have a good dispersibility and stability in mixed solvents of ethylene glycol and methanol for two weeks under air atmosphere conditions. In addition, these fluorinated Cu nanocomposite powders have been found to be stable for more than three months.     

Novel self-assembled molecular aggregates formed by fluoroalkyl end-capped oligomers and their application

A variety of fluoroalkyl end-capped oligomers were prepared under mild conditions by the use of fluoroalkanoyl peroxide as a key intermediate. These oligomers can form the self-assembled molecular aggregates with the aggregations of end-capped fluoroalkyl groups in aqueous and organic media. Fluorinated self-assembled molecular aggregates containing carboxyl and sulfo groups were suggested to interact with positively charged HIV-1 to exhibit a potent anti-HIV-1 activity in vitro. In contrast, fluoroalkyl end-capped oligomers containing cationic segments exhibited not only the unique surface active properties imparted by fluorine as well as the usual low-molecular fluorinated surfactants, but also high surface antibacterial activity. Fluoroalkyl end-capped oligomers containing betaine-type segments were found to cause a gelation where the strong aggregation of the end-capped fluoroalkyl groups is involved in establishing the physical gel network in water and polar organic solvents under non-crosslinked conditions. Similarly, fluoroalkyl end-capped oligomers containing hydroxyl groups could cause a gelation, where the aggregation of fluoroalkyl groups and hydrogen-bonding interaction is involved in establishing a physical gel network in water and polar organic solvents under non-crosslinked conditions. Fluoroalkanoyl peroxide is also a convenient tool for the preparation of new fluoroalkyl end-capped oligomers containing recognition moieties such as diacetone segments. These fluorinated oligomers containing recognition moieties could form the self-assembled molecular aggregates to recognize selectively the hydrophilic amino and N,N-dimethylamino compounds as guest molecules.     

Fluoroalkyl end‐capped oligomers possessing nonflammable characteristic in calcium carbonate nanocomposites

Calcium chloride reacted with sodium carbonate in the presence of a variety of fluoroalkyl end‐capped oligomers such as fluoroalkyl end‐capped acrylic acid oligomer (R_F‐[ACA]_n‐R_F), 2‐methacryloyloxyethanesulfonic acid oligomer (R_F‐[MES]_n‐R_F), N,N‐dimethylacrylamide oligomer (R_F‐[DMAA]_n‐R_F) and acryloylmorpholine oligomer (R_F‐[ACMO]_n‐R_F) to afford the corresponding fluorinated oligomers/calcium carbonate composites. Each fluorinated oligomer/calcium carbonate composite thus obtained is nanometer size‐controlled very fine particles (25–114 nm) possessing a good dispersibility and stability in a variety of solvents including water. Thermal stability of these fluorinated calcium carbonate nanocomposites was studied by thermogravimetic analyses measurements. Fluorinated oligomes, in which the theoretical oligomer content in the composites is 19%, were able to give no weight loss corresponding to the content of oligomer in each case even after calcination at 800 °C. On the other hand, a slight weight loss corresponding to the contents of oligomers in the composites after calcination at 800 °C was observed in R_F‐(MES)_n‐R_F/, R_F‐(DMAA)_n‐R_F/ and R_F‐(ACMO)_n‐R_F/calcium carbonate nanocomposites, in which the theoretical contents of the oligomers were 36–53%, although R_F‐(ACA)_n‐R_F/calcium carbonate nanocomposites gave a clear weight loss corresponding to the contents of oligomer under similar conditions. Fluorinated oligomers/calcium carbonate nanocomposites possessing no weight loss at 800 °C were applied to the surface modification of poly(methyl methacrylate) (PMMA) to exhibit a good oleophobicity imparted by fluorines on the surfaces. Interestingly, these fluorinated calcium carbonate nanocomposites after calcination at 800 °C were found to exhibit the similar oleophobic characteristic on the modified PMMA surfaces as well as that of the nanocomposites before calcination. Copyright © 2013 John Wiley & Sons, Ltd.     

Preparation of novel fluoroalkyl end-capped oligomers/silica hybrid nanoparticles-encapsulation of a variety of guest molecules into fluorinated nanoparticles

Fluoroalkyl end-capped oligomers reacted with tetraethoxysilane and silica/nanoparticles under alkaline conditions to afford fluoroalkyl end-capped oligomers/silica nanoparticles (mean diameters: 31–54 nm) with a good dispersibility and stability in organic media. Interestingly, the isolated fluorinated particle powders were found to afford nanometer size-controlled colloidal particles with a good redispersibility and stability in these media. In addition, fluoroalkyl end-capped oligomers/silica nanoparticles-encapsulated guest molecules such as stable organic radicals and ionic liquids were prepared under similar conditions. These fluorinated nanoparticles-encapsulated guest molecules were applied to a new type of surface-modification agent, and these particles were able to disperse well above the poly (methyl methacrylate) films.     

Dispersion of nanodiamond into organic media by the use of fluoroalkyl end‐capped oligomers—applications to surface modification of poly(methyl methacrylate) with the dispersed nanodiamond

Self‐assembled fluorinated molecular aggregates formed by fluoroalkyl end‐capped oligomers were able to interact with nanodiamond powders to afford well‐dispersed fluorinated aggregates‐diamond nanocomposites in organic media, and these fluorinated aggregates‐diamond nanocomposites were applied to the surface modification of poly(methyl methacryate) films. Copyright © 2005 John Wiley & Sons, Ltd.     

Solubilization of fullerene into water with fluoroalkyl end-capped amphiphilic oligomers-novel fluorescence properties

Solubilization of fullerene into water was studied by the use of fluoroalkyl end-capped acryloylmorpholine oligomers, N,N-dimethylacrylamide oligomers, and acrylic acid oligomers. In these fluorinated oligomers, fluoroalkyl end-capped acryloylmorpholine oligomers were more effective in solubilizing fullerene into water. Interestingly, the aqueous solutions of fullerene were applicable to fluorescence analyses.     

Synthesis and applications of novel fluorinated dendrimer-type copolymers by the use of fluoroalkanoyl peroxide as a key intermediate

Fluoroalkanoyl peroxide reacted with 1,3,5,7-tetravinyl-1,3,5,7-tetramethylcyclotetrasiloxane (TTRV-Si) to afford fluoroalkyl end-capped oligomers containing some unreacted vinyl segments under very mild conditions. Fluoroalkyl end-capped cyclosiloxane oligomers containing some vinyl segments thus obtained reacted with N,N-dimethylacrylamide and fluoroalkanoyl peroxide to afford new fluorinated dendrimer-type block copolymers in good isolated yield. Similar reactions were also occurred by the use of 1,3,5-trivinyl-1,3,5-trimethylcyclotrisiloxane instead of TTRV-Si, and the corresponding fluorinated dendrimer-type block copolymer was obtained in good isolated yield. These fluorinated dendrimer-type block copolymers had an excellent solubility not only in water but also in traditional organic solvents including aliphatic fluorinated solvents. Interestingly, these fluorinated block copolymers were found to form the self-assembled dendrimer-type polymeric aggregates in aqueous solutions. More interestingly, these fluorinated block copolymers had an extremely higher dispersion ability of not only single-walled carbon nanotube and fullerenes but also magnetic nanoparticles into water, compared to that of the corresponding two fluoroalkyl end-capped oligomers.     

Preparation of self-assembled fluorinated molecular aggregates, fluorescein nanocomposites: an extremely enhanced light absorption in nanocomposites

Self-assembled fluorinated molecular aggregates formed by fluoroalkyl end-capped N-(1,1-dimethyl-3-oxobutyl)acrylamide oligomers, N,N-dimethylacrylamide oligomers, and acrylic acid oligomers in methanol could selectively recognize fluoresceins as guest molecules to form a new class of fluorinated aggregates-fluorescein nanocomposites. These fluorinated fluorescein nanocomposites that are obtained exhibit an extraordinarily enhanced light absorption (_max ca. 440 nm) compared to that (_maxs 452, 480 nm) of the parent fluorescein in the absence of fluorinated aggregates.     

Preparation and applications of novel fluoroalkyl end‐capped vinyltrimethoxysilane oligomer/hydroxyapatite nanocomposites

Novel fluoroalkyl end‐capped vinyltrimethoxysilane oligomer/hydroxyapatite (HAp) nanocomposites were prepared by the reaction of calcium nitrate tetrahydrate and phosphoric acid in the presence of the corresponding oligomer. These fluorinated oligomer/HAp composites thus obtained are nanometer size‐controlled fine particles (83–173 nm), and were found to exhibit good dispersibility in methanol, ethanol, and isopropyl alcohol. These fluorinated HAp nanocomposites were applied to the surface modification of glass and poly(methyl methacrylate) (PMMA) to exhibit good hydro‐ and oleophobic characteristics imparted by fluorine on their surface. In addition, the surface structural changes of the modified polyethylene terephtalate and PMMA films treated with these fluorinated nanocomposites before and after soaking in a simulated body fluid (SBF) were analyzed by using SEM, XRD, and EDX to observe the formation of spherical HAp deposits on the surface. Copyright © 2009 John Wiley & Sons, Ltd.     

Solubilization and applications of single-walled carbon nanotubes into aqueous and organic media by the use of nanometer size-controlled fluoroalkyl end-capped oligomeric aggregates

We have studied on the solubilization of single-walled carbon nanotubes (SW-CNTs) into aqueous and organic media by the use of a variety of nanometer size-controlled fluorinated self-assemblies, which were formed by the aggregations of end-capped fluoroalkyl segments in fluoroalkyl end-capped acrylic acid oligomers [R_F-(ACA)_n-R_F], N,N-dimethylacrylamide oligomers [R_F-(DMAA)_n-R_F], acryloylmorpholine oligomers [R_F-(ACMO)_n-R_F], and N-(1,1-dimethyl-3-oxobutyl)acrylamide oligomers [R_F-(DOBAA)_n-R_F]. Fluorinated self assemblies formed in organic media (colorless solutions) could solubilize SW-CNTs into organic media to afford the transparent pale yellow solutions. The dynamic light scattering measurements showed that the size of fluorinated self-assemblies increased after the solubilization of SW-CNTs into organic media. It was suggested that the solubilization of SW-CNTs into organic media is due to the encapsulation of SW-CNTs into fluorinated assemblies. Fluorinated assemblies were also able to solubilize SW-CNTs into water to give the transparent gray solutions. Among a variety of fluorinated assemblies, fluorinated assemblies formed by R_F-(ACMO)_n-R_F [R_F = CF(CF₃)OC₆F₁₃] oligomer was more effective for the solubilization of SW-CNTs into both aqueous and organic media. Contact angle measurements of dodecane and the fluorescence spectra for poly(methyl methacrylate) cast film modified by fluorinated self-assemblies—SW-CNTs complexes showed that SW-CNTs are dispersed above the PMMA surface.     

Preparation and applications of novel fluoroalkyl end-capped acrylamide oligomers/polythiophene nanocomposites

Thiophene monomer reacted with ferric chloride in the presence of a variety of fluoroalkyl end-capped N-(1,1-dimethyl-3-oxobutyl)acrylamide oligomers [R_F-(DOBAA)_x-R_F] to afford nanometer size-controlled R_F-(DOBAA)_x-R_F oligomers-polythiophene composites [R_F-(DOBAA)_x-R_F/PTh]. R_F-(DOBAA)_x-R_F/PTh nanocomposites thus obtained were demonstrated to have a good dispersibility and stability in methanol to give a transparent brown solution. In addition, these fluorinated nanocomposites were applied to the surface modification of common organic polymers such as poly(methyl methacrylate), and were dispersed regularly above the polymer surface.     

Coloring-decoloring behavior of amphiphilic fluoroalkyl end-capped N-(1,1-dimethyl-3-oxobutyl)acrylamide--acryloylmorpholine cooligomer/fluorescein nanocomposites in protic and aprotic solvents

Amphiphilic fluoroalkyl end-capped N-(1,1-dimethyl-3-oxobutyl)acrylamide-acryloylmorpholine cooligomer/fluorescein nanocomposites afforded brilliant yellow-colored solutions in not only protic solvents such as methanol and ethanol but also protic-like solvents such as dichloromethane and 1,2-dichloroethane, respectively. However, the corresponding non-fluorinated cooligomer/fluorescein composites and parent fluorescein gave the colorless solutions under similar conditions. On the other hand, unexpectedly, such brilliant yellow-colored solutions provided by these fluorinated nanocomposites completely disappeared in aprotic solvents such as N,N-dimethylformamide, dimethyl sulfoxide, and tetrahydrofuran. Thus, these fluorinated fluorescein nanocomposites can exhibit a coloring-decoloring behavior through solvatochromic response.     

Synthesis and properties of novel fluoroalkyl end‐capped oligomers having adamantane units in the main chains via a radical process

Fluoroalkanoyl peroxides were reacted with adamantane in the presence of radical polymerizable monomers such as acrylic acid, acryloylmorpholine, and N,N‐dimethylacrylamide to afford fluoroalkyl end‐capped oligomers having adamantane units in the main chains via a radical process under very mild conditions. Thermal stability of these new fluorinated adamantane co‐oligomers thus obtained became higher than that of the corresponding fluorinated homo‐oligomers having no adamantane units. Interestingly, these fluorinated adamantane co‐oligomers exhibited good solubility in traditional organic solvents such as methanol, ethanol, tetrahydrofuran, chloroform, benzene, dimethylsulfoxide and N,N‐dimethylformamide including water, although the parent adamantane exhibited no solubility in water, methanol and dimethylsulfoxide. Furthermore, these adamantane co‐oligomers were able to reduce the surface tension effectively to form the nanometer size‐controlled self‐assembled fluorinated molecular aggregates. Copyright © 2005 John Wiley & Sons, Ltd.     

Preparation of magnetic nanoparticles by the use of self-assembled fluorinated oligomeric aggregates—A new approach to the dispersion of magnetic particles on poly(methyl methacrylate) film surface

Fluoroalkyl end-capped acrylic acid oligomer-encapsulated magnetic nanoparticles were prepared by the coprecipitation of aqueous ferric and ferrous ions in the presence of the corresponding oligomers under alkaline conditions. The dynamic light scattering measurements showed that these fluorinated oligomer magnetic nanoparticles were encapsulated in the self-assemblies of fluoroalkyl end-capped oligomers. Fluoroalkyl end-capped oligomer-encapsulated magnetic nanoparticles thus obtained were applied to the dispersion of magnetic particles on the poly(methyl methacrylate) film surface to exhibit not only the surface active property imparted by fluorine but also magnetic behavior toward a permanent magnet.     

Preparation of colloidal stable fluoroalkyl end‐capped oligomer/silver nanocomposites––application to the surface modification of traditional organic polymers with these nanocomposites

A variety of fluoroalkyl end‐capped oligomers/silver nanocomposites were prepared by the reactions of silver ions with poly(methylhydrosiloxane) in the presence of fluoroalkyl end‐capped N,N‐dimethylacrylamide oligomer, N‐(1,1‐dimethyl‐3‐oxobutyl)acrylamide oligomer, N,N‐dimethylacrylamide cooligomer containing poly(dimethylsiloxane) segments in organic media such as toluene and 1,2‐ dichloroethane. These fluorinated oligomers/silver nanocomposites thus obtained were found to exhibit clear plasmon absorption bands around 420 nm related to the formation of silver nanoparticles. In particular, these composites could display narrow plasmon absorptions around 420 nm in toluene by the addition of trioctylamine (TOA). On the other hand, the corresponding non‐fluorinated N‐(1,1‐ dimethyl‐3‐oxobutyl)acrylamide oligomer was not able to afford such a plasmon absorption under similar conditions. These fluorinated oligomers/silver nanocomposites in organic media have been found to be stable for more than 10 days. Transmission electron microscopy (TEM) and dynamic light scattering (DLS) measurements showed that silver nanoparticles could be effectively encapsulated into fluorinated oligomeric aggregate cores to afford colloidal stable fluorinated oligomers/silver nanocomposites. Fluorinated oligomers/silver nanocomposites were also applied to the surface modification of traditional organic polymers such as polystyrene (PSt) and poly(methyl methacrylate) (PMMA) to exhibit not only a good oleophobicity imparted by fluorine but also a higher surface antibacterial activity related to the silver nanoparticles on their surface. Copyright © 2007 John Wiley & Sons, Ltd.     

Preparation and properties of novel cross-linked fluoroalkyl end-capped cooligomeric nanoparticles possessing double decker-type aromatic silsesquioxane segments as core units

Cross-linked fluoroalkyl end-capped cooligomers possessing double decker-type aromatic silsesquioxane segments as core units [R_F-(Ar-SiSQ) _x -(Co-M) _y -R_F] were prepared under mild conditions by the cooligomerizations of fluoroalkanoyl peroxide with the corresponding aromatic silsesquioxane possessing bifunctional vinyl groups (Ar-SiSQ) and comonomers (Co-M) such as acryloylmorpholine (ACMO), N,N-dimethylacrylamide (DMAA) and N-(1,1-dimethyl-3-oxobutyl)acrylamide (DOBAA). Interestingly, these cross-linked fluorinated cooligomers thus obtained were found to form the nanometer size-controlled nanoparticles with a good dispersibility in a variety of solvents including fluorinated aliphatic solvents. These fluorinated cooligomeric nanoparticles were demonstrated to have red-shifted fluorescent emissions related to the presence of aromatic silsesquioxane segments, compared with that of parent aromatic silsesquioxane, indicating that each aromatic moiety in these nanoparticles can interact effectively with each other through the π–π stacking between the aromatic moieties to afford the red-shifted fluorescent emissions. These fluorinated nanoparticles were also applied to the surface modification of poly(methyl methacrylate) (PMMA) to exhibit not only a good oleophobicity imparted by fluorine but also a fluorescent emission behavior related to aromatic silsesquioxane segments in nanoparticles on the modified PMMA surface. More interestingly, cross-linked R_F-(Ar-SiSQ) _x -(DOBAA) _y -R_F cooligomeric nanoparticles interacted with fluorescein to give the corresponding fluorinated cooligomeric particles/fluorescein nanocomposites in methanol. These fluorinated fluorescein nanocomposites were found to afford an extraordinarily enhanced light absorption (λ _max = 441 nm), compared with that of fluoroalkyl end-capped DOBAA oligomer [R_F-(DOBAA) _n -R_F] possessing no aromatic silsesquioxane segments.