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1.
    
This work describes a strategy of assembling horizontally oriented Ag nanoplates (AgNPTs) with PSS‐Ag as the precursor of silver by the layer‐by‐layer (LbL) technique on planar substrates. These AgNPTs have a lateral dimension of 20–80 nm and a thickness of 9–12 nm. A corresponding formation mechanism of these AgNPTs is discussed considering the orientation of the polyelectrolytes molecules, as well as their confinement effect on the diffusion of Ag nanoparticles. The exposed horizontal surfaces of the AgNPTs correspond to low free energy; they show an active antimicrobial activity. No Staphylococcus aureus colonies appear on the nutrient agar medium inoculated and incubated with S. aureus solutions treated by LbL films containing AgNPTs. The horizontally oriented AgNPTs by the described strategy in this work not only provides a novel method for controlled assembly of AgNPTs, but also provides insight in the antimicrobial behavior of nanoplate surfaces with low free energy. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42070.  相似文献   

2.
    
Chitosan‐graft‐β‐cyclodextrin (CS‐g‐β‐CD) copolymer was synthesized by conjugating β‐cyclodextrins to chitosan molecules through click chemistry. The copolymer structure was characterized by Fourier transform infrared spectroscopy (FTIR) and nuclear magnetic resonance (NMR). CS‐g‐β‐CD/CMC nanoparticles were prepared by a polyelectrolyte complexation process in aqueous solution between CS‐g‐β‐CD copolymer and carboxymethyl chitosan (CMC), which was used to load anticancer drug (Doxorubicin hydrochloride, DOX·HCl) with hydrophobic group. The particle size, surface charge, zeta potential, and morphology of the nanoparticles were characterized with dynamic light scattering. The drug loading efficiency and in vitro release of DOX·HCl of the nanoparticles were measured by ultraviolet spectrophotometer. The results demonstrated that the size, surface charge and drug loading efficiency of the nanoparticles could be modulated by the fabrication conditions. The drug loading efficiency of CS‐g‐β‐CD/CMC nanoparticles was improved from 52.7% to 88.1% because of the presence of β‐CD moieties with hydrophobic cavities, which can form inclusion complexes with the drug molecules. The in vitro release results showed that the CS‐g‐β‐CD/CMC nanoparticles released DOX·HCl in a controlled manner, importantly overcoming the initial burst effect. These nanoparticles possess much potential to be developed as anticancer drug delivery systems, especially those drugs with hydrophobic group. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 41034.  相似文献   

3.
    
A soluble polyimide was synthesized from 2,2′‐bis[4‐(3,4‐dicarboxyphenoxy)phenyl]propane dianhydride (BPADA) and 3,3′‐dimethyl‐4,4′‐diaminodiphenylmethane (DMMDA) by a two‐step method, and it had good solubility both in strong bipolar solvents and in common low‐boiling‐point solvents. The BPADA–DMMDA polyimide was dissolved in chloroform (CHCl3) and cast onto a glass substrate in a humid atmosphere. The BPADA–DMMDA/CHCl3 solution easily formed honeycomb films. Some affecting factors, such as the polymer solution concentration, atmospheric humidity, and solvent volatility, were tested. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008  相似文献   

4.
    
Enhanced oil recovery (EOR) processes aim to recover trapped oil left in reservoirs after primary and secondary recovery methods. New materials and additives are needed to make EOR economical in challenging reservoirs or harsh environments. Nanoparticles have been widely studied for EOR, but nanoparticles with polymer chains grafted to the surface—known as polymer‐coated nanoparticles (PNPs)—are an emerging class of materials that may be superior to nanoparticles for EOR due to improved solubility and stability, greater stabilization of foams and emulsions, and more facile transport through porous media. Here, we review prior research, current challenges, and future research opportunities in the application of PNPs for EOR. We focus on studies of PNPs for improving mobility control, altering surface wettability, and for investigating their transport through porous media. For each case, we highlight both fundamental studies of PNP behavior and more applied studies of their use in EOR processes. We also touch on a related class of materials comprised of surfactant and nanoparticle blends. Finally, we briefly outline the major challenges in the field, which must be addressed to successfully implement PNPs in EOR applications. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40576.  相似文献   

5.
Novel tri‐armed star polystyrene‐block‐poly(N‐isopropylacrylamide) block copolymers with trimesic acid as central molecules were synthesized by successive two‐step atom transfer radical polymerization, and confirmed by Fourier‐transform infrared spectra, 1H nuclear magnetic resonance, and laser light scattering gel chromatography system. The copolymers could self‐assemble into spherical core‐shell micelles in aqueous media independent on drug loading. Physicochemical properties of the blank and drug‐loaded micelles were examined by surface tension, fluorescence spectroscopy, UV‐vis, transmission electron microscope, and dynamic light scattering measurements. The copolymer micelles exhibited thermo‐triggered phase transition, with low critical solution temperature of 33.7 and 34.6°C, varying with copolymer compositions. The critical aggregate concentrations were 11.62 and 47.61 mg L?1, and hydrodynamic diameters from 200 to 220 nm. Water‐insoluble 10‐hydroxycamptothecine was encapsulated into the micelle aggregates to investigate the change in the resulting physicochemical parameters, thermo‐triggered in vitro drug release, and the applicability as drug targeting release carriers. MTT assays were carried out to uncover cytotoxicity of the newly developed micelle‐based drug formulations. © 2014 American Institute of Chemical Engineers AIChE J, 61: 35–45, 2015  相似文献   

6.
    
2‐Hydroxyethyl methacrylate polymer brushes with various grafting densities and chain lengths were prepared through surface‐initiated atom transfer radical polymerization. X‐ray photoelectron spectra, ellipsometry measurement, contact angle measurement, and atom force microscope were used to characterize the prepared polymer brush. The biofouling assays of polymer brush were investigated by adhesion of Dunaliella tertiolecta, Navcular sp., and Bovine Serum Albumin protein and by static marine immersion field test. Besides, hydroxyl and sulfonate‐terminated self‐assembled monolayers, anionic charged 3‐sulfopropyl methacrylate potassium salt polymer brush were prepared for comparison. Results suggest that the settlement of microorganisms can be largely reduced by polymer with enough polymer chain length and grafting density. More importantly, static immersion field tests indicate that hydrophilic polymer film with enough hydration layer thickness is necessary for long‐term marine antifouling application. This comprehensive investigation is of great importance to understanding their influence on the adhesion of marine microorganism. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46232.  相似文献   

7.
    
The spontaneous formation of well‐ordered microstructures is an interesting research topic because such formation is useful for cost‐effective production of functional materials. In this article, we report a novel method for spontaneous formation of a discrete arrangement of particles using an ultraviolet/ozone‐treated poly(dimethylsiloxane) substrate. The substrate was first dipped in a solution (solvent: mixture of methanol and water, solute: sucrose or lithium perchlorate) in a sealed vessel filled with the vapor of the solvent, and was then dried in air to precipitate the solute as particles. In spite of the simplicity of the procedure, the particles were regularly and discretely arranged in a triangular lattice with a distance between the neighboring particles of about 48 µm. The mechanism of formation of the array was explained by considering the formation of regular dimples due to swelling of the substrate surface with the solution and the dewetting of the liquid film of the solution on the surface. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43506.  相似文献   

8.
    
Hydrophobically modified water‐soluble polymers have been prepared by copolymerization of 2‐acrylamido‐2‐methylpropane sulfonic acid (AMPS) and isodecyl methacrylate (iDMA) in N,N‐dimethylformamide under nitrogen atmosphere, varying the composition feed. Fluorescence spectroscopy was used to further confirm the copolymers self‐aggregate in water. Critical concentration of the self‐aggregate formation (CAC) decreased by increasing the molar fraction of iDMA in the AMPSco copolymers and varied between 1.20 and 0.04 g/L depending on the degree of hydrophobic modification. Hence, copolymer composition and charge density allowed tuning the pseudomicellar characteristics of these new amphiphilic copolymers. The addition of a salt or a low‐molecular‐weight surfactant was studied. Binding of CTAB to the AMPSco copolymers leads to a high decrease of CAC, i.e., 0.006 g/L. Effect of the composition in the viscosimetric behavior of the hydrophobically modified copolymers AMPSco was investigated. The removal of single metal ions, Cu2+, and m‐cresol from aqueous solutions by ultrafiltration with the help of the copolymers was investigated. Equilibrium dialysis experiments demonstrate that the formation of hydrophobic microdomains can be used to control the sequestration of foulants, and thus these novel copolymers have potential application as polymeric surfactants in micellar‐enhanced ultrafiltration processes for water purification. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007  相似文献   

9.
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10.
    
An easy approach was reported to achieve the simultaneous reinforcement and toughening of polypropylene (PP) via thermally induced self‐assembly of β‐nucleating agent (TMB‐5). The results showed that the processing temperatures dictated the solubility and self‐assembly of TMB‐5 in the polymer melts to determine the subsequent morphology development of PP. At low processing temperature, TMB‐5 did not dissolve into the polymer melt but remained original shape to induce PP to crystallize into spherulites so that it only promoted the formation of β‐form crystals to enhance the toughness of the samples. At high processing temperature, TMB‐5 gradually dissolved into the polymer melts. On cooling, the dissolved nucleating agent self‐assembled into high aspect ratio fibrils through intermolecular hydrogen‐bonding interactions. Due to a favorable matching between PP and TMB‐5, PP preferred to nucleate and grow orthogonally to the fibril axis and into oriented hybrid shish‐kebab morphology with rich β‐form crystals. Compared with isotropic spherulites, the anisotropic structure exhibited excellent properties of the β‐form crystal and shish‐kebab morphology to simultaneously improve the strength and toughness of TMB‐5‐modified PP samples. With the increasing processing temperature, more dissolved TMB‐5 was involved in the self‐assembly procedure to generate longer fibrils and induce more lamellae to grow on the surface. As a consequence, the anisotropy of the PP samples increased further, bringing out more improvements of the tensile strength. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40605.  相似文献   

11.
    
The self‐assembly of pH‐responsive poly (methyl methacrylate‐co‐acrylic acid) latex particles at emulsion droplet interfaces was achieved. Raising pH increases the hydrophilicity of the latex particles in situ and the latex particle acts as an efficient particulate emulsifier self‐assembling at emulsion droplet interface at around pH 10–11 but exhibits no emulsifier activity at higher pH. This effect can be reversibly induced simply by varying the aqueous phase pH and thus the latex emulsifier can be reassembled. The effect factors, including the aqueous phase pH, the surface carboxyl content, ζ‐Potential of the latex particles and oil phase solvent have been investigated. Using monomer as oil phase, the latex particles could stabilize emulsion droplets during polymerization and cage‐like polymer microspheres with hollow core/porous shell structure were obtained after polymerization. The mechanism of the latex particles self‐assembly was discussed. The morphologies of emulsion and microspheres were characterized by optical microscopy, scanning electron microscopy, and transmission electron microscopy. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007  相似文献   

12.
    
Polystyrene (PSt) or poly(vinylbenzyl chloride) (PVBC) crosslinked with divinylbenzyl (DVB) materials were synthesized through free radical polymerization into templates formed by the surfactant polyoxyethylene (4) lauryl ether (Brij‐30). The chemical composition of the final products was verified through attenuated total reflectance infrared spectroscopy (ATR‐IR) and the thermal behavior was investigated through thermogravimetric analysis (TGA). Depending on the organization of Brij‐30 in aqueous solution, three characteristic structures, namely spherical nanoparticles, platelet‐like objects and three‐dimensional networks, were identified through scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The spherical nanoparticles and the platelet‐like objects form rather stable dispersions, especially in aqueous surfactant solutions, as exemplified by the evolution of the turbidity of the PSt‐based materials, using sodium dodecyl sulfate as surfactant. All materials retain their integrity even after thermal treatment at high temperature (～200–250°C). The benzyl chloride group of the PVBC‐based materials offers a significant potential for further elaboration and practical applications, since they can be further functionalized while retaining their integrity. This potential is demonstrated here through hydrolysis to obtain hydroxyl‐functionalized three‐dimensional networks. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43297.  相似文献   

13.
    
Polystyrene latex dispersions were prepared by emulsion polymerization, using a mixture of hydrophobically modified Inulin (INUTEC® SP1) and various nonionic surfactants (cosurfactants). Two series of nonionic surfactants were used, namely Synperonic A (C13–15 alkyl chain with 7, 11, and 20 moles of ethylene oxide, EO) and Synperonic NP (nonylphenol with 10 and 15 moles of EO). For 5 wt % latex, the INUTEC SP1 concentration was kept constant at 0.0165 wt % and the initiator concentration was also kept constant at 0.0125 wt %, whereas the cosurfactant concentration was varied between 0.1 and 0.5 wt %. With the exception of Synperonic A20, all other cosurfactants showed an initial increase in particle diameter followed by a decreased reaching a value comparable with that obtained using INUTEC SP1 alone. However, A20 produced a continuous reduction in particle diameter with increase of surfactant concentration, reaching a value of 100 nm at 0.5 wt % which is lower than the value obtained using INUTEC SP1 alone (188 nm). In all cases, addition of a cosurfactant enhanced the stability of latexes by co‐adsorption at the solid–liquid interface. The enhanced stability produced by the addition of cosurfactants to INUTEC SP1 could be illustrated by using the mixture of INUTEC SP1 and Synperonic A7 at 40 wt % of styrene latex concentration. In this case, the mixture produced lower particle size, much lower polydispersity index and much higher stability. These results are of significant value for industrial applications. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008  相似文献   

14.
    
A variety of fluoroalkyl end‐capped 3‐[N‐(3‐acrylamido)propyl‐N,N‐dimethylammonio]propanesulfonate polymers [RF–(APDAPS)n–RF] were prepared by the reactions of fluoroalkanoyl peroxides with the corresponding monomer under very mild conditions. Similarly, fluoroalkyl end‐capped 2‐vinylpyridinio propane sulfonate polymer was obtained by the use of fluoroalkanoyl peroxide. These fluoroalkyl end‐capped sulfobetaine polymers exhibited a good solubility in water; however, these polymers have a poor solubility in other solvents. In particular, RF–(APDAPS)n–RF polymers caused gelation in methanol, although RF–(VPPA)n–RF polymer showed no gelation in methanol. RF–(APDAPS)n–RF polymers were found to form the self‐assembled molecular aggregates with the aggregations of the end‐capped fluoroalkyl segments and the ionic interactions between sulfobetaine segments in aqueous solutions. On the other hand, it was suggested that RF–2‐vinylpyridinio propane sulfonate (VPPS)n–RF polymer is not likely to form the self‐assemblies in aqueous solutions because of the steric hindrance of pyridiniopropyl betaine units in polymer. We also studied the surfactant properties of RF–(APDAPS)n–RF and RF–(VPPS)n–RF polymers compared with those of other fluoroalkyl end‐capped betaine‐type polymers such as 2‐acrylamido‐2‐methylpropanesulfonic acid polymers and 2‐(3‐acrylamidopropyldimethylammonio) ethanoate polymers. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 1144–1153, 2004  相似文献   

15.
    
The speed and scalability of film fabrication can dictate the translation of technologies from the laboratory scale to industrial level mass production. Spray‐assisted layer‐by‐layer (LbL) film assembly enables the rapid coating of geometrically complex and porous substrates with functional polyelectrolyte multilayers. Unfortunately, the encapsulation efficiency can be as low as one percent, making this technique prohibitively costly with even modestly priced materials. Herein, we used containment chambers to separately capture the aerosolized solutions for each step in the spray‐LbL process and analyzed the effect of recycling on multilayer film assembly. With potential biomedical applications, we studied the controlled release films of (Poly 2/heparin/lysozyme/heparin)n films and tracked the distribution of lysozyme after film assembly. In a “Conventional” Spray‐LbL protocol, only 6% of the aerosolized lysozyme is incorporated into the film. By collecting and returning the expended solutions to their respective reservoirs (Recycle Spray‐LbL), we increased this efficiency to 15%. We also tuned the final distribution of lysozyme by adjusting the spray times (Optimized Spray‐LbL), which minimized the amount of lysozyme lost to non‐specific adsorption and reduced the fraction of lysozyme lost to the wash step from 30% and 75% (Conventional and Recycle Spray‐LbL, respectively) to 13%. Despite the changes in film assembly parameters, each film demonstrated similar controlled release properties. With the inherent limitations of time and cost facing Dip and Conventional Spray‐LbL technologies, respectively, the implementation of recycling to the latter demonstrates improvements in efficiency and time that may make it more attractive for the manufacture of biomedical coatings. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43563.  相似文献   

16.
    
An aqueous core containing a disinfectant agent (chlorhexidine digluconate) was encapsulated in a poly(methyl acrylate) shell with a modified nanoprecipitation technique. After redispersion of the capsules in an aqueous medium, the remaining amount of the disinfectant agent was as high as 90%. The nanocapsules were successfully adsorbed via the layer‐by‐layer technique onto a γ‐radiation‐vulcanized natural rubber latex sheet. Water contact angle measurements and scanning electron microscopy confirmed the presence of nanocapsules on the rubber surface. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009  相似文献   

17.
    
The friction coefficient of the sulphur‐prevulcanized natural rubber (SPNR) film could be effectively reduced by deposition of poly(methyl methacrylate) (PMMA) particles. The nanoscale surface roughness of rubber, determined by atomic force microscope, was directly proportional to the particle size of PMMA particle at 12% surface coverage (Cs). The %Cs and surface roughness of the modified SPNR increased, while the friction coefficient decreased, with increasing PMMA latex concentration and immersion time. By using a mixture of latexes having both large and small sizes, the increase in the amount of small particles resulted in the better distribution of large particles deposited on the rubber surface. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010  相似文献   

18.
    
Injection of bionic synovial fluid (BSF) is a conventional method to improve the lubricity of artificial joints, but BSF cannot maintain long due to the dilution and degradation of BSF in human body. To prolong the effectiveness of hyaluronic acid (HA), which is the major component of BSF, this study applies a temperature‐sensitive poly(?‐caprolactone)–poly(ethylene glycol)–poly(?‐caprolactone) (PCEC) hydrogel loaded with HA to achieve long‐term lubrication. In addition, Fourier transform infrared, nuclear magnetic resonance analysis, X‐ray diffraction, scanning electron microscopy (SEM), and gel permeation chromatography spectra were used to analyze the structure of the synthetic hydrogel. Rheological test and test tube inverting method were used to characterize the thermosensitivity. The lubrication properties of the released solution were characterized by UV–vis, tribological tests, SEM, and 3D laser confocal scanning microscope. The experimental results reveal that the triblock PCEC hydrogel contains both hydrophilic block and hydrophobic block, and both PCEC and PCEC/HA hydrogels have phase‐changed effect when the temperature increases from room temperature to body temperature. Moreover, the friction coefficient of the released solution from PCEC/HA hydrogel is approximatively 38% lower than that of phosphate buffer saline. And the ability of shear resistance and creep recovery of PCEC/HA hydrogel are better than that of PCEC hydrogel. This study provides an effective approach to achieve long‐time lubrication effect for artificial joints. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46228.  相似文献   

19.
    
Polymeric micelles can be designed and synthesized to bear polymeric blocks with different hydrophilicities; this triggers their self‐assembly into micellar aggregates similar to those generated with traditional surfactants. The basic structure consists of a hydrophobic core, capable of containing guest substances, and a hydrophilic shell, which stabilizes the payload and protects it from external degradation or prevents its quick elimination from the body. The accumulation of block copolymer micelles (BCMs) in a target cell or tissue can be accomplished by two main mechanisms, passive and active targeting; this allows the payload release at the site of action when desired. Hence, in this general overview, we pay special attention to newly developed single‐stimulus‐ and multi‐stimuli‐responsive delivery systems capable of disassembling and reassembling (in some cases) as a response to changes in their physicochemical properties. Also, special interest is also devoted to multifunctional BCMs incorporating multiple therapeutic agents and/or multiple imaging contrast agents, which can be considered the new generation (third generation) of drug‐delivery systems, that is, nanotheranostic platforms. Finally, a summary of BCM‐based drug‐delivery systems currently under clinical trials is given. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42650.  相似文献   

20.
    
Fluorescent cellulose nanocrystals (CNCs) were prepared through a two‐step approach. Reactive amino groups were first introduced onto the CNCs through a silanization reaction with 3‐aminopropyltrimethoxysilane. The fluorescent moieties were then attached onto the cellulose by covalent grafting between the amino groups and 1‐pyrenebutyric acid N‐hydroxy succinimide ester or fluorescein isothiocyanate. The synthesized fluorescent CNCs were investigated and characterized with attenuated total reflectance Fourier transform infrared spectroscopy, ultraviolet–visible absorbance and fluorescence spectroscopy, confocal microscopy, and dynamic light scattering. The same fluorescent functionalization strategy could also be applied to other cellulose materials, such as microcrystalline cellulose and bulky paper sheets. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010  相似文献   

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