Complexation and coacervation of polyelectrolytes with oppositely charged colloids

Kizilay, Ebru; Kayitmazer, A. Basak; Dubin, Paul L.

doi:10.1016/j.cis.2011.06.006

Cited by 364 publications

(394 citation statements)

References 95 publications

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“…Less viscous material will increase shear rate thus produce smaller particle. This finding was supported by [40] that size of the coacervate suspensions decreased with decrease in viscosity of the material. …”

Section: Ft-ir Spectrasupporting

confidence: 77%

Microencapsulation of citronella oil by complex coacervation using chitosan-gelatin (b) system: operating design, preparation and characterization

et al. 2016

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Abstract. Citronella oil (CO) can be an effective mosquito repellent, but due to its nature which having high volatility, oils rapidly evaporates causing loss of efficacy and shorten the repellent effect. Therefore, microencapsulation technology was implemented to ensure the encapsulated material being protected from immediate contact with environment and offers controlled release. In this study, microencapsulation of CO was done by employing complex coacervation using chitosan-gelatin (B) system and utilized proanthocyanidins as the crosslinker. Remarkably, nearly all material involved in this study are from natural sources which are safe to human and environment. In designing operating process condition for CO encapsulation process, we found that wall ratio of 1:35 and pH 5 was the best operating condition based on zeta potential and turbidity analysis. FT-IR analysis found that gelatin-B had coated the CO droplet during emulsification stage, chitosan started to interact with gelatin-B to form a polyelectrolyte complex in adjust pH stage, CO capsules solidified at cooling process and were hardened during crosslinking process. Final product of CO capsules after settling process was identified at the top layer. Surface morphology of CO capsules obtained in this study were described having diameter varies from 81.63 Pm to 156.74 Pm with almost spherical in shape.

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Section: Ft-ir Spectrasupporting

confidence: 77%

Microencapsulation of citronella oil by complex coacervation using chitosan-gelatin (b) system: operating design, preparation and characterization

et al. 2016

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“…Oparin's hypothesis has however been dismissed in modern theories of the origin of life, particularly after the discovery of DNA as the genetic material [7]. Most of the earlier studies on polyelectrolyte complexation focused on coacervation of natural polymers such as albumin and gelatin, but recent studies [2,3,[8][9][10][11][12] have extended this to the complexation of synthetic polyelectrolytes. Renewed scientific interest in polyelectrolyte complexation is due, in part, to its use in polyelectrolyte assemblies and multilayer films [13,14], which have many technological applications [15,16].…”

Section: Introductionmentioning

confidence: 99%

pH and Salt Effects on the Associative Phase Separation of Oppositely Charged Polyelectrolytes

et al. 2014

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Abstract:The classical Voorn-Overbeek thermodynamic theory of complexation and phase separation of oppositely charged polyelectrolytes is generalized to account for the charge accessibility and hydrophobicity of polyions, size of salt ions, and pH variations. Theoretical predictions of the effects of pH and salt concentration are compared with published experimental data and experiments we performed, on systems containing poly(acrylic acid) (PAA) as the polyacid and poly(N,N-dimethylaminoethyl methacrylate) (PDMAEMA) or poly(diallyldimethyl ammonium chloride) (PDADMAC) as the polybase. In general, the critical salt concentration below which the mixture phase separates, increases with degree of ionization and with the hydrophobicity of polyelectrolytes. We find experimentally that as the pH is decreased below 7, and PAA monomers are neutralized, the critical salt concentration increases, while the reverse occurs when pH is raised above 7. We predict this asymmetry theoretically by introducing a large positive Flory parameter (= 0.75) for the interaction of neutral PAA monomers with water. This large positive Flory parameter is supported by molecular dynamics simulations, which show much weaker hydrogen bonding between neutral PAA and water than between charged PAA and water, while neutral and charged PDMAEMA show similar numbers of hydrogen bonds. This increased hydrophobicity of neutral PAA at reduced pH increases the tendency towards phase separation despite the reduction in charge interactions between the polyelectrolytes. Water content and volume of coacervate are found to be a strong function of the pH and salt concentration.

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“…This type of mechanical characterization can give insight into the molecular-level interactions present in the material, and is critical to enable effective processing of these materials. Generally, coacervates have been reported to have a Newtonian, or a shear-rate independent viscosity [71,111,171,172], as well as a shear thinning response [2,87,111,124,[171][172][173][174][175], depending on the shear rate. The occurrence of shear thinning is suggestive of a structural change in the material, and research has suggested that the tendency for shear thinning in coacervate-based materials may correlate with the strength of the underlying electrostatic interactions [2,174].…”

Section: Viscositymentioning

confidence: 99%

Linear viscoelasticity of complex coacervates

Liu

Winter

Perry

2017

Advances in Colloid and Interface Science

125

163

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Rheology is a powerful method for materials characterization that can provide detailed information about the self-assembly, structure, and intermolecular interactions present in a material. Here, we review the use of linear viscoelastic measurements for the rheological characterization of complex coacervate-based materials. Complex coacervation is an electrostatically and entropically-driven associative liquid-liquid phase separation phenomenon that can result in the formation of bulk liquid phases, or the self-assembly of hierarchical, microphase separated materials. We discuss the need to link thermodynamic studies of coacervation phase behavior with characterization of material dynamics, and provide parallel examples of how parameters such as charge stoichiometry, ionic strength, and polymer chain length impact self-assembly and material dynamics. We conclude by highlighting key areas of need in the field, and specifically call for the development of a mechanistic understanding of how molecular-level interactions in complex coacervate-based materials affect both selfassembly and material dynamics.

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Complexation and coacervation of polyelectrolytes with oppositely charged colloids

Cited by 364 publications

References 95 publications

Microencapsulation of citronella oil by complex coacervation using chitosan-gelatin (b) system: operating design, preparation and characterization

Microencapsulation of citronella oil by complex coacervation using chitosan-gelatin (b) system: operating design, preparation and characterization

pH and Salt Effects on the Associative Phase Separation of Oppositely Charged Polyelectrolytes

Linear viscoelasticity of complex coacervates

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