Vapor-Phase Free Radical Polymerization in the Presence of an Ionic Liquid

Haller, Patrick; Frank-Finney, Robert J.; Gupta, Malancha

doi:10.1021/ma102807n

Cited by 34 publications

(48 citation statements)

References 39 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Ionic liquids have been investigated in radical polymerization since several years as summarized and discussed in several reviews . Compared to the use of traditional solvents, rates of polymerization are mostly higher in ionic liquids, and molecular weights are often increased .…”

Section: Introductionmentioning

confidence: 99%

Ionic Liquids as Advantageous Reaction Media for Free Radical Polymerization

Strehmel

Wetzel

Laschewsky

2014

Macromolecular Symposia

View full text Add to dashboard Cite

Ionic liquids are attractive solvents for polymer synthesis because their properties can be easily and broadly tuned by varying the structure of both the cation and the anion. Application of ionic liquids as reaction medium for free radical polymerization of vinyl monomers, such as methacrylates or styrene, results in high yields and high molecular weights of the polymers. Reasons for these effects are only partially due to the high viscosity of ionic liquids, which may reduce bimolecular termination of the propagating chains, but are also due to solvent cage effects that differ from those in traditional organic solvents because of strong ionic interactions between the individual ions of the ionic liquids. Furthermore, the high dissolving power of ionic liquids for both weakly polar as well as highly polar monomers makes ionic liquids interesting as solvents for statistical copolymerization. Interestingly, variation of the alkyl chain length of substituents at the cation of the ionic liquid allows altering of copolymer composition.

show abstract

Section: Introductionmentioning

confidence: 99%

Ionic Liquids as Advantageous Reaction Media for Free Radical Polymerization

Strehmel

Wetzel

Laschewsky

2014

Macromolecular Symposia

View full text Add to dashboard Cite

show abstract

“…We used a quartz crystal microbalance to ensure that neither the n -butyl acrylate nor the 4-vinylpyridine monomer signifi cantly absorbs into the PDMS so that polymerization will only occur at the liquid-vapor interface and will not occur within the bulk liquid. [ 21 ] We deposited the polymers onto the uncured PDMS for 5 min and then observed the cured PDMS using a scanning electron microscope (SEM). The equilibrium contact angle of uncured PDMS liquid on a P n BA fi lm is 21° so the particles should not submerge based on the equation for Δ G , which is what we found as shown in Figure 1 A, which includes multiple particles to show the size distribution and Figure 1 C, which is a magnifi ed image of the larger particles.…”

Section: Resultsmentioning

confidence: 99%

Synthesis of Polymer Nanoparticles via Vapor Phase Deposition onto Liquid Substrates

Haller

Gupta

2014

Macromol. Rapid Commun.

View full text Add to dashboard Cite

In this article, the growth of polymer nanoparticles formed at the liquid-vapor interface via vapor phase polymerization is studied. The particles grow by polymer aggregation, which is driven by the surface tension interaction between the liquid and polymer. It is demonstrated that the mechanism of particle growth is determined by whether polymer particles remain at the liquid-vapor interface or submerge into the liquid. The position of the particles depends on the interaction between the polymer and the liquid. For example, the deposition of poly(n-butyl acrylate) onto poly(dimethyl siloxane) and Krytox liquids leads to the formation of nanoparticles that remain at the liquid-vapor interface. The size of these particles increases as a function of deposition time. The deposition of poly(4-vinylpyridine) onto poly(dimethyl siloxane) and Krytox leads to the formation of nanoparticles that submerge into the liquid. The size of these particles does not significantly change with deposition time. Our study offers a new rapid, one-step synthetic approach for fabricating functional polymer nanoparticles for applications in catalysis, photonics, and drug delivery.

show abstract

“…The increased thickness at the center of the film is caused by the integration of polymer chains that form within the bulk IL since polymerization takes place simultaneously at both the vapor−IL interface and within the IL at the conditions used for our study. 9 Similar to PHEMA, the deposition of poly(N-isopropylacrylamide) (PNIPAAm) also results in polymer particles on silicone oil and polymer skins on each of the three ILs. Therefore, we can use our fabrication method to form shaped PNIPAAm films.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

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

2011

View full text Add to dashboard Cite

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...

show abstract

Vapor-Phase Free Radical Polymerization in the Presence of an Ionic Liquid

Cited by 34 publications

References 39 publications

Ionic Liquids as Advantageous Reaction Media for Free Radical Polymerization

Ionic Liquids as Advantageous Reaction Media for Free Radical Polymerization

Synthesis of Polymer Nanoparticles via Vapor Phase Deposition onto Liquid Substrates

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

Contact Info

Product

Resources

About