Surface active ionic liquids: Study of the micellar properties of 1-(1-alkyl)-3-methylimidazolium chlorides and comparison with structurally related surfactants

The impetus for the increasing interest in studying surface active ionic liquids (SAILs; ionic liquids with long-chain ""tails"") is the enormous potential for their applications, e.g., in nanotechnology and biomedicine. The progress in these fields rests on understanding the relationship between surfactant structure and solution properties, hence applications. This need has prompted us to extend our previous study on 1-(1-hexadecyl)-3-methylimidazolium chloride to 1-(1-alkyl)-3-methylimidazolium chlorides, with alkyl chains containing 10, 12, and 14 carbons. In addition to investigating relevant micellar properties, we have compared the solution properties of the imidazolium-based surfactants with: 1-(1-alkyl)pyridinium chlorides, and benzyl (2-acylaminoethyl)dimethylammonium chlorides. The former series carries a heterocyclic ring head-group, but does not possess a hydrogen that is as acidic as H2 of the imidazolium ring. The latter series carries an aromatic ring, a quaternary nitrogen and (a hydrogen-bond forming) amide group. The properties of the imidazolium and pyridinium surfactants were determined in the temperature range from 15 to 75 degrees C. The techniques employed were conductivity, isothermal titration calorimetry, and static light scattering. The results showed the important effects of the interactions in the interfacial region on the micellar properties over the temperature range studied. (C) 2011 Elsevier Inc. All rights reserved.

Micellar properties of surface active ionic liquids: A comparison of 1-hexadecyl-3-methylimidazolium chloride with structurally related cationic surfactants

Ionic liquids, ILs, carrying long-chain alkyl groups are surface active, SAIIs. We investigated the micellar properties of the SAIL 1-hexadecyl-3-methylimidazolium chloride, C(16)MeImCl, and compared the data with 1-hexadecylpyridinium chloride, C(16)PYCl, and benzyl (3-hexadecanoylaminoethyl)dimethylammonium chloride, C(15)AEtBzMe(2)Cl. The properties compared include critical micelle concentration, cmc; thermodynamic parameters of micellization; empirical polarity and water concentrations in the interfacial regions. In the temperature range from 15 to 75 degrees C, the order of cmc in H(2)O and in D(2)O is C(16)PYCl > C(16)MeImCl > C(15)AEtBzMe(2)Cl. The enthalpies of micellization, Delta H(mic)(degrees), were calculated indirectly from by use of the van`t Hoff treatment; directly by isothermal titration calorimetry, ITC. Calculation of the degree of counter-ion dissociation, alpha(mic), from conductivity measurements, by use of Evans equation requires knowledge of the aggregation numbers, N(agg), at different temperatures. We have introduced a reliable method for carrying out this calculation, based on the volume and length of the monomer, and the dependence of N(agg) on temperature. The N(agg) calculated for C(16)PyCl and C(16)MeImCl were corroborated by light scattering measurements. Conductivity- and ITC-based Delta H(mic)(degrees) do not agree; reasons for this discrepancy are discussed. Micelle formation is entropy driven: at all studied temperatures for C(16)MeImCl; only up to 65 degrees C for C(16)PyCl; and up to 55 degrees C for C(15)AEtBzMe(2)Cl. All these data can be rationalized by considering hydrogen-bonding between the head-ions of the monomers in the micellar aggregate. The empirical polarities and concentrations of interfacial water were found to be independent of the nature of the head-group. (C) 2010 Elsevier Inc. All rights reserved.

Raman spectra of polymer electrolytes based on poly(ethylene glycol) dimethyl ether, lithium perchlorate, and the ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate

Raman spectra of polymer electrolytes based on poly(ethylene glycol) dimethyl ether (PEGdME) with LiClO(4), PEGdME/LiClO(4), and the ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate, PEGdME/[bmim]PF(6), are compared. Raman spectroscopy suggests stronger interactions in PEGdME/LiClO(4) than PEGdmE/[bmim]PF(6), thus corroborating previous results obtained by molecular dynamics simulations. Quantum Chemistry methods have been used to calculate vibrational frequencies and the equilibrium structure of segments of the polymer chain around the cation. A consistent picture has been obtained from Raman spectroscopy, density functional theory (DFT) calculations, and molecular dynamics simulations for these polymer electrolytes. (C) 2010 Elsevier B.V. All rights reserved.

Perspective: LaGuardia Community College Newsletter Vol. 1, No. 3

"A newsletter published periodically to keep the faculty, students, staff, and community informed about the activities taking place on the campus of LaGuardia Community College." No date [1973]; Vol. 1, No. 3; 4 pages; Color (green, black & white); black & white photographs. Cover article: “COMMENCEMENT SPEAKER NAMED, SHIRLEY CHISHOLM TO DELIVER GRADUATION ADDRESS”. Other entries include: “FIORELLO FUNDS COMMITTEE ANNOUNCES F INAL AWARDS;” “’TOWN MEETINGS’ PROGRAMS TO BEGIN ON TELEVISION MARCH 17;” “Highights of BLACK HISTORY WEEK.”

March 2012: Volume 1 Issue 3

In this Issue: Summertime, But the Livin' "Ain't" EasyDacus Library of Winthrop UniversityStudent Works on Medlin Papers and Efforts on Friends Endowment

Avaliação de IGF-1 (Insulin-like growth factor-1), IGFBP-1 e IGFBP-3 (Insulin-like to growth binding protein-1 e 3) no fluído folicular de pacientes infertéis com endometriose

Resumo não disponível.

New Ventures Brasil (Forum 2008) - Sustentabilidade empresarial (Parte 1, 2, 3)

Sustentabilidade empresarial: do capital somente à Bolsa de Valores - Luiz Maia - Instituto BM&FBOVESPA - Mario Monzoni - GVces / FGV-EAESP

New Ventures Brasil (Forum 2008) - Mesa redonda (Parte 1, 2, 3)

Mesa redonda - Cenário de investimento em negócios verdes - André Vitti - Axial Gestão, Fabio Bellotti - São Paulo Anjos, Juliano Graff- Master Minds, Oren Pinsky - Grupo Stratus, Renato Marques - Finep - Mediadora: Elisabeth Lerner - Tripod Investments

Mudanças climáticas: uma realidade (trailer parte 1, 2, 3)

Secas extremas, inundações, furacões, pessoas que perderam suas casas, suas plantações, seus animais, sua fé. Essa é a realidade enfrentada por brasileiros em diversas regiões do País. A causa? As mudanças do clima. Apesar de muita gente ainda achar que aquecimento global é coisa de cinema ou que só acontecerá daqui a muitas gerações, o documentário do Greenpeace "Mudanças do Clima, Mudanças de Vidas" mostra que tudo isso já é, infelizmente, uma realidade. Confira ao lado o filme e clique no menu acima para adquirir a sua cópia

Climate Justice: manifestação em Copenhague (partes 1, 2, 3 e 4)

Protesto realizado em 9/12, dia em que foi cancelada plenária que discutiria vinculação legal do acordo global. Manifestantes pediram teto de 1.5 graus para aumento de temperatura e posições ousadas e contundentes dos países em desenvolvimento

EPC: palestra com Paul Hardisty (parte 1, 2, 3 e 4)

A plataforma brasileira Empresas pelo Clima recebeu no dia 4 de maio Paul Hardisty, Diretor global da divisão EcoNomics & Sustainability da Worley Parsons, para uma apresentação sobre cases de sucesso em que a gestão de emissão de gases de efeito estufa foi aplicada como medida de adaptação às mudanças climáticas globais

Palestra - Wilson Nobre - (parte 1, 2, 3, 4, 5 e 6)

Em palestra realizada no dia 04 de julho, o professor Wilson Nobre (membro fundador e pesquisador do Fórum de Inovação da FGV-EAESP), falou sobre Inovação na Cadeia de Valor

Videoaula sobre precificação de carbono (partes 1, 2, 3, 4, 5 e 6)

Esta é uma das seis partes da videoaula que integra o conteúdo do especial P22_ON sobre precificação de carbono. Nesta série, a pesquisadora do GVces Inaiê Takaes Santos faz um exercício teórico no qual analisa o custo-benefício da tributação e do sistema de comércio de emissões

Lançamento da cartilha de políticas públicas em empreendedorismo: conteúdo e experiências (partes 1, 2, 3 e 4)

Laçamento da cartilha desenvolvimento de políticas públicas de fomento ao empreendedorismo em estados e municípios e políticas públicas de fomento ao empreendedorismo e às micro e pequenas empresas do projeto de pesquisa empowering brazilian states to Improve business environment, financiado pela Embaixada Britânica por meio do Prosperity Fund e elaborada por pesquisadores da Fundação Getúlio Vargas, do Centro de Estudos em Administração Pública e Governo (CEAPG) e do Centro de Empreendedorismo e Novos Negócios (CENN)