Binary coalescence of air bubbles in viscous liquids in presence of non‐ionic surfactant

Giribabu, K.; Ghosh, Pallab

doi:10.1002/cjce.20086

Cited by 6 publications

(9 citation statements)

References 29 publications

(41 reference statements)

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“…The number or growth rate of micro-bubbles increased with the concentration of surfactant (P407) in solution, as well as air amount incorporated in the solution (i.e., more shaking times) [ 18 ]. The stability of micro-bubbles in solution was positively correlated with the concentration or viscosity of surfactant [ 19 ]. Thus, micro-bubbles would suspend in solution for a period because of the viscosity of the P407 solution.…”

Section: Discussionmentioning

confidence: 99%

Floating Hydrogel with Self-Generating Micro-Bubbles for Intravesical Instillation

et al. 2016

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Intravesical instillation is the main therapy for bladder cancer and interstitial cystitis. However, most drug solutions are eliminated from bladder after the first voiding of urine. To solve this problem, we proposed a floating hydrogel with self-generating micro-bubbles as a new delivery system. It floated in urine, avoiding the urinary obstruction and bladder irritation that ordinary hydrogels caused. In this study, we abandoned traditional gas-producing method like chemical decomposition of NaHCO3, and used the foamability of Poloxamer 407 (P407) instead. Through simple shaking (just like shaking SonoVue for contrast-enhanced ultrasound in clinical), the P407 solution will “lock” many micro-bubbles and float in urine as quickly and steadily as other gas producing materials. In vivo release experiments showed that drug was released continually from hydrogel for 10 h during the erosion process. Thus, the residence time of drug in bladder was prolonged and drug efficacy was improved. In vivo efficacy study using rabbit acute bladder injury model showed that prolonged drug residence time in bladder increased the efficiency of heparin in the protection of bladder mucosal permeability. Therefore, our floating hydrogel system with self-generating micro-bubbles was single-component, simply prepared and efficacy enhancing, successfully exempting users from worries on safety and clinical efficiency from bench to bedside.

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Section: Discussionmentioning

confidence: 99%

Floating Hydrogel with Self-Generating Micro-Bubbles for Intravesical Instillation

et al. 2016

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“…With increasing concentration of the salt, the electrostatic repulsive force decreases due to the presence of a 15 Effect of concentration of Span 80 on binary coalescence time of air bubbles in ethylene glycol 11 16 Effect of concentration of ethyl alcohol on coalescence time of air bubbles at flat air/water interface 5 5 Kumar and Ghosh, 7 Giribabu et al 9 and Bommaganti et al 10 In presence of certain surfactants and salts (e.g. SDS and LiCl, or CTAB and NaBr), the bubble does not coalesce at all.…”

Section: Effect Of Electrolyte In Presence Of Ionic Surfactantsmentioning

confidence: 99%

Coalescence of bubbles in liquid

Ghosh¹

2009

Bubble Science, Engineering & Technology

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Coalescence of bubbles is important for the destabilisation of gas-liquid dispersions. The theories of coalescence used at present are reviewed. The film drainage theory and the stochastic theory of coalescence have been discussed with their merits and drawbacks. The influence of van der Waals, electrostatic double layer, steric and solvation forces on the coalescence process has been discussed. The importance of adsorption of surfactant molecules at the air/water interface in presence and in absence of salt on coalescence time has been explained. Difference between the experimental conditions under which the foam films collapse and the bubble coalescence experiments has been pointed out. Possible reasons behind the failure of the film drainage models in predicting the coalescence time have been explained. Some directions for future research have also been discussed. List of symbolsa bubble radius, m a f area of the film, m 2 A surface area, m 2 A H Hamaker constant, J A min minimum surface area per adsorbed surfactant molecule, m 2 B modified Hamaker constant, J m c concentration of surfactant in the bulk solution, mol m 23 c s concentration of salt in the bulk solution, mol m 23 c ? i concentration of ions of type i in the bulk solution, mol m 23 C 1 ,C 2 constants in equation (14), N m 21 D C surface diffusivity, m 2 s 21 e electronic charge, C f r repulsive force generated by one mole of the surfactant at the barrier ring, N mol 21 F(t R ) cumulative probability distribution of coalescence time F h hydration force, N g acceleration due to gravity, m s 22 h film thickness, m h c critical film thickness, m k Boltzmann's constant, J K 21 K L equilibrium constant in Langmuir isotherm, m 3 mol 21 l length of a polymer segment, m L thickness of the polymer brush layer, m n ' number of ions per unit volume in the bulk solution, m 23 n s number of segments of the polymer molecule N total number of ruptured films N A Avogadro's number, mol 21 p pressure, Pa P C dimensionless coalescence threshold R gas constant, J mol 21 K 21 R b radius of barrier ring, m R m radius of curved surface, m s mean distance between the attachment points, m S C normalised standard deviation t time, s t c coalescence time, s t characteristic diffusion time, s T temperature, K w b width of the barrier ring, m z valence a fraction of C that remains at the barrier ring after the displacement of the surfactant molecules to the barrier ring c surface tension, N m 21 C surface excess, mol m 22 C mean value of the distribution of surface excess C, mol m 22 C number of adsorbed chains per unit area, m 22 C ' adsorption capacity, mol m 22 C m minimum value of the surfactant concentration at the barrier ring required to prevent coalescence, mol m 22 d separation between the surfaces, m Dp excess pressure in the film, Pa Dr density difference between the two phases, kg m 23 e dielectric constant of the medium e 0 permittivity of free space, C 2 J 21 m 21 k Debye-Hü ckel parameter, m 21 l i zeros of the Bessel function of the first kind and order one J ...

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“…In combination with other techniques, such as dynamic surface tension, surface potential or surface rheological measurements, these coalescence cells allow for a qualitative understanding of the mechanisms involved in the rate of film thinning and rupture, especially through relative comparison of different systems. While there are many studies on the coalescence of polymeric and ionic surfactants, as reviewed by Chaudhari and Hofmann [10], only few works report on the coalescence of bubbles in the presence of non-ionic surfactants [9,11,12]. The main mechanism of bubble stabilization, which has been proposed in these publications is steric stabilization.…”

Section: Introductionmentioning

confidence: 97%

“…In a more macroscopic approach, other types of devices have also been used to study phenomenologically the stability of isolated bubbles against coalescence [5][6][7][8][9]. In most of these devices, bubble stability is measured indirectly by recording a coalescence time spectrum and/or the evolution of bubble size as a function of time.…”

Section: Introductionmentioning

confidence: 99%