Adsorption of Poly(vinylpyrrolidone)/Surfactant(s) Mixtures at the Silica/Water Interface: A Calorimetric Investigation

Thibaut, A; Misselyn-Bauduin, Anne-Marie; Broze, Guy; Jérôme, Robert

doi:10.1021/la000834v

Cited by 19 publications

(21 citation statements)

References 57 publications

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“…When the surfactant and the polymer have no attractive interactions but can both adsorb to the surface, a clear competitive mechanism is observed, − similar to the competition for interfaces between different polymer chains. , Here parameters such as the molecular weight of the polymer chain and the concentration and exact composition of the surfactant will determine which of the components dominates the adsorption to the interface . Much more focus has, however, been on systems in which the surfactant and the polymer have attractive interactions, for example, for nonionic polymers such as poly(ethylene oxide) (PEO) and poly(vinylpyrrolidone) (PVP), with the surfactant sodium dodecyl sulfate (SDS). ,− In these systems, the components have often been found to adsorb to the surface in a cooperative fashion. The combined adsorption of polymers and surfactants can significantly enhance or diminish colloidal stability …”

Section: Introductionmentioning

confidence: 99%

Adsorption and Surfactant-Mediated Desorption of Poly(vinylpyrrolidone) on Plasma- and Piranha-Cleaned Silica Surfaces

et al. 2014

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Optical flow cell reflectometry was used to study the adsorption of poly(vinylpyrrolidone) (PVP) to a silica surface and the subsequent surfactant adsorption and polymer desorption upon exposure to the anionic surfactant sodium dodecyl sulfate (SDS). We have studied these effects as a function of pH and surfactant concentration, but also for two different methods of silica preparation, O2 plasma and piranha cleaning. As a function of pH, a plateau in the amount adsorbed of ∼0.6 mg/m(2) is observed below a critical pH, above which the adsorption decreases to zero within 2-3 pH units. An increase in pH leads to dissociation of surface OH groups and a decreased potential for hydrogen bonding between the polymer and surface. For the plasma- and piranha-cleaned silica, the critical pH differs by 1-2 pH units, a reflection of the much larger amount of surface OH groups on piranha-cleaned silica (for a given pH). Subsequent rinsing of the adsorbed layer of PVP with an SDS solution leads to total or partial desorption of the PVP layer. Any remaining adsorbed PVP then acts as an adsorption site for SDS. A large difference between plasma- and piranha-cleaned silica is observed, with the PVP layer adsorbed to plasma-cleaned silica being much more susceptible to desorption by SDS. For a plasma-cleaned surface at pH 5.5, only 30% of the originally adsorbed PVP is remaining, while for piranha-cleaned silica, the pH can be increased to 10 before a similar reduction in the amount of adsorbed PVP is seen. For a given pH, piranha-cleaned silica has a higher surface charge, leading to a smaller amount of adsorbed SDS per PVP chain on a piranha-cleaned surface compared to a plasma-cleaned surface under identical conditions. In that way, the high negative surface charge makes desorption by negatively charged SDS more difficult. The high surface charge thus protects the neutral polymer from surfactant-mediated desorption.

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Section: Introductionmentioning

confidence: 99%

Adsorption and Surfactant-Mediated Desorption of Poly(vinylpyrrolidone) on Plasma- and Piranha-Cleaned Silica Surfaces

et al. 2014

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“…17 It was concluded that the surfactant−polymer interactions were very weak, and both species adsorb at the interface without forming complexes. Changing the charges in the system once more to give repulsive interactions between surface and surfactant, Thibaut et al 16 investigated the PVP/SDS/silica system using flow microcalorimetry and total concentration depletion. They found that PVP and SDS form "amalgamates" at the water/silica interface and that the amount and structure of PVP adsorbed were dependent on the SDS concentration.…”

Section: ■ Introductionmentioning

confidence: 99%

Surfactant-Mediated Desorption of Polymer from the Nanoparticle Interface

et al. 2012

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The surfactant-mediated desorption of adsorbed poly(vinylpyrrolidone), PVP, from anionic silica surfaces by sodium dodecyl sulfate, SDS, was observed. While photon correlation spectroscopy shows that the size of the polymer-surfactant-particle ensemble grows with added SDS, a reduction in the near-surface polymer concentration is measured by solvent relaxation NMR. Volume fraction profiles of the polymer layer extracted from small-angle neutron scattering experiments illustrate that the adsorbed polymer layer has become more diffuse and the polymer chains more elongated as a result of the addition of SDS. The total adsorbed amount is shown to decrease due to Coulombic repulsion between the surfactant-polymer complexes and between the complexes and the anionic silica surface.

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“…Há estudos da adsorção da PVP em sílica [16,17] , em alumina [18,19] , em caulinita [20] e em zircônio [21] . Francis e Levy [30] foram os primeiros pesquisadores a estudar a adsorção da PVP em montmorilonita, embora somente bastante tempo depois a investigação da natureza desta ligação viesse a ser realizada [22,23] .…”

Section: Resultsunclassified

Estudo do processo de intercalação via solução PVP-bentonita: a avaliação da influência do tempo reacional, da proporção de polímero-argila e da massa molar média

Dornelas¹,

Grillo²,

Irinaldo³

et al. 2010

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Resumo: Foram produzidas reações, via solução, PVP-bentonita (natural e organicamente modificada) nas quais foi estudada a influência das variáveis: tempo reacional (15, 30, 45 minutos, 1, 24, 48, 72 horas), proporção polímero-argila (2:1, 1:1, 1:2) e massa molar média (PVP K-30, PVP K-90). Com o auxílio de técnicas de difração de raios X (XRD), infravermelho com transformada de Fourier (FTIR) e análise termogravimétrica (TGA) foi possível não somente elucidar a formação de nanocompósitos intercalados como também o seu processo reacional. Palavras-chave: PVP, bentonita, nanocompósito polímero-silicato lamelar, intercalação. Study of PVP- IntroduçãoAinda hoje, não há uma definição realmente adequada para um material compósito. Reinhart e Clements (apud Botelho, 2006) [1] definem um compósito como uma combinação macroscópica de dois ou mais materiais distintos, havendo uma interface reconhecível entre eles. Nesta combinação, os constituintes retêm suas identidades. Deste modo, os compósitos têm, tipicamente, uma ou mais fases descontínuas, usualmente mais rígida e resistente, envolvidas por uma fase contínua, ou matriz. Os nanocompósitos são materiais modificados, da mesma forma do que os compósitos, no entanto, diferentemente destes, aqueles contêm pelo menos um dos componentes do reforço ou carga de dimensões nanométricas [2] . A nanotecnologia está relacionada a estruturas, propriedades e processos envolvendo materiais com dimensões numa escala de 1 a 100 nm [3] , valores estes considerados elevados quando comparados a moléculas simples, porém pequenos em relação ao comprimento de onda da luz visível. Os componentes de um nanocompósito podem ser de natureza inorgânica/inorgânica, orgânica/orgânica, ou, ainda, inorgânica/orgânica, de propriedades mais diferenciadas [4] . Dentre as diferentes fontes de nanomateriais de origem natural, destacamse os argilominerais, os quais apresentam inumeráveis aplicações e ampla diversidade de uso, o que se deve à facilidade com que esses materiais são modificados [5] . Nos últimos anos, os nanocompósitos poliméricos têm emergido como uma nova classe de materiais revolucionários, por demonstrarem incremento em uma série de propriedades [6,7]

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Adsorption of Poly(vinylpyrrolidone)/Surfactant(s) Mixtures at the Silica/Water Interface: A Calorimetric Investigation

Cited by 19 publications

References 57 publications

Adsorption and Surfactant-Mediated Desorption of Poly(vinylpyrrolidone) on Plasma- and Piranha-Cleaned Silica Surfaces

Adsorption and Surfactant-Mediated Desorption of Poly(vinylpyrrolidone) on Plasma- and Piranha-Cleaned Silica Surfaces

Surfactant-Mediated Desorption of Polymer from the Nanoparticle Interface

Estudo do processo de intercalação via solução PVP-bentonita: a avaliação da influência do tempo reacional, da proporção de polímero-argila e da massa molar média

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