Size-Exclusion “Capture and Release” Separations Using Surface-Patterned Poly(<i>N</i>-isopropylacrylamide) Hydrogels

Castellanos, Alexandro; DuPont, Samuel J.; Heim, August J.; Matthews, Garrett; Stroot, Peter G.; Moreno, Wilfrido; Toomey, Ryan

doi:10.1021/la700338p

Cited by 37 publications

(31 citation statements)

References 27 publications

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“…That is, the alkyl groups are dehydrated on phase separation and an attractive interaction between polymer segments lead extended polymer chains to shrunk and globular conformation. The phenomenon has attracted a keen attention from both basic and technological points of view in the last two decades [4][5][6][7]. In particular, the phase transition of poly(N-isopropylacrylamide) (PiPA) in water has been extensively studied by using various methods (IR [8], Raman [9], NMR [10], and fluorescence [11] spectroscopy, calorimetry [12], light scattering [13], neutron scattering [14], and so on).…”

Section: Introductionmentioning

confidence: 99%

A unique phase behavior of random copolymer of N-isopropylacrylamide and N,N-diethylacrylamide in water

Maeda

Yamabe

2009

Polymer

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Section: Introductionmentioning

confidence: 99%

A unique phase behavior of random copolymer of N-isopropylacrylamide and N,N-diethylacrylamide in water

Maeda

Yamabe

2009

Polymer

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“…The free-standing PNIPAAm films have many potential uses due to their temperature-responsive hydrophilicity. 29,30 Our fabrication process is environmentally friendly because no organic solvents are used in any of the steps and ionic liquids are nonvolatile, nonflammable, and can be easily recycled. We demonstrated the generality of our fabrication 4 ]).…”

Section: ■ Conclusionmentioning

confidence: 99%

Ultrathin Free-Standing Polymer Films Deposited onto Patterned Ionic Liquids and Silicone Oil

2011

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We studied the vapor deposition of polymers onto the surfaces of silicone oil and imidazolium-based ionic liquids (ILs). We found that the deposition of poly(2-hydroxyethyl methacrylate) (PHEMA) and poly(N-isopropylacrylamide) (PNIPAAm) resulted in polymer particles on silicone oil whereas continuous polymer skins formed on 1-butyl-3-methylimidazolium hexafluorophosphate ([bmim][PF 6 ]), 1-butyl-3-methylimidazolium tetrafluoroborate ([bmim][BF 4 ]), and 1-ethyl-3-methylimidazolium tetrafluoroborate ([emim][BF 4 ]). The silicone oil and ILs were patterned onto a common substrate by exploiting their different wetting properties. Ultrathin free-standing PHEMA and PNIPAAm films of different shapes were produced by confining the shape of the IL within a wax barrier, surrounding it with silicone oil, and then depositing the polymer. The silicone oil prevented the polymer film from connecting to the underlying substrate and maintained the shape of the polymer film during deposition. Our process allows for multidimensional control over the resulting free-standing film: the area of the shape can be controlled by patterning the IL, and the thickness of the film can be controlled by adjusting the duration of polymer deposition. The films are highly pure and do not contain any residual monomer or solvent entrapment which extends their potential applications to include in vivo biomedical research. ■ INTRODUCTIONThe initiated chemical vapor deposition (iCVD) technique is a one-step, solventless free radical polymerization process that can be used to deposit a wide range of polymer films such as poly(2-hydroxyethyl methacrylate) (PHEMA), 1 poly(4-vinylpyridine) (P4VP), 2 and poly(1H,1H,2H,2H-perfluorodecyl acrylate) (PPFDA). 3 The iCVD technique is typically used to deposit polymer coatings onto solid substrates such as silicon wafers, 4 membranes, 5 wires, 6 carbon nanotubes, 7 and fibers. 8 We recently demonstrated the ability to deposit polymer coatings onto ionic liquids (ILs). 9 ILs are salts that are liquids at ambient temperatures, and they have recently attracted significant interest as environmentally friendly alternatives to traditional volatile organic solvents because they are nonvolatile, nonflammable, and can be easily recycled. 10,11 Our previous work examined the deposition of PHEMA and PPFDA in the presence of 1-butyl-3-methylimidazolium hexafluorophosphate ([bmim][PF 6 ]) droplets. We found that polymerization occurred at the vapor−IL interface and/or within the bulk IL depending on the solubility of the monomer within the IL and the reaction conditions such as the duration of deposition and stage temperature.In this paper, we use iCVD to deposit polymers onto silicone oil for the first time. We observe different polymer morphologies on the silicone oil as compared to the ILs, and we exploit this difference to fabricate ultrathin free-standing polymer films of different shapes by combining the silicone oil and ILs onto a common substrate. The generality of our fabrication method is demonstrated for multiple po...

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“…The hydrogel swells in water below the LCST and shrinks as the temperature increases. Due to this special property, PNIPAAm hydrogels have attracted great attention in biomedical and bioengineering applications such as drug delivery systems, separation operations, biosensors, and immobilization of enzymes [2][3][4][5][6][7]. However, the PNIPAAm hydrogels prepared by conventional methods are often restricted in their application due to very slow swelling/deswelling rates in response to an external stimulus.…”

Section: Introductionmentioning

confidence: 99%

Macroporous Poly(N‐isopropylamide‐co‐acrylamide) Hydrogels Prepared by Two‐Step Polymerization for Drug Delivery Applications

Huo

Hou

et al. 2010

Chem Eng & Technol

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Macroporous poly(N-isopropylamide-co-acrylamide) [P(NIPAAm-co-AAm)] hydrogels were successfully prepared by a two-step polymerization method. The initial polymerization was carried out at 18°C with different duration, followed by freezing polymerization at -18°C for 24 h. The results showed that the immediate performance of freezing polymerization played a dominant role in the final properties of the P(NIPAAm-co-AAm) hydrogels. The thermoresponsive rate and mechanical strength of the hydrogels were drastically changed by freezing the reaction mixture after 3 min of the first polymerization (PNA-3). Scanning electron microscopy (SEM) studies revealed that the hydrogel frozen after 3 min exhibited the most highly interconnected porous structures and the largest pore size. These open pore structures were very useful to accelerate the responsive rate of the hydrogels. In vitro BSA (bovine serum albumin) release from the hydrogel PNA-3 exhibited relatively small initial burst release followed by a steady release. Such results demonstrated that the P(NIPAAm-co-AAm) hydrogels frozen before gelation have the potential to be applicated for delivering proteins.

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Size-Exclusion “Capture and Release” Separations Using Surface-Patterned Poly(N-isopropylacrylamide) Hydrogels

Cited by 37 publications

References 27 publications

A unique phase behavior of random copolymer of N-isopropylacrylamide and N,N-diethylacrylamide in water

A unique phase behavior of random copolymer of N-isopropylacrylamide and N,N-diethylacrylamide in water

Ultrathin Free-Standing Polymer Films Deposited onto Patterned Ionic Liquids and Silicone Oil

Macroporous Poly(N‐isopropylamide‐co‐acrylamide) Hydrogels Prepared by Two‐Step Polymerization for Drug Delivery Applications

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