Bubble–surface interactions with graphite in the presence of adsorbed carboxymethylcellulose

Abstract

The adsorption of carboxymethylcellulose (CMC), and the subsequent effect on bubble-surface interactions, has been studied for a graphite surface. CMC adsorbs on highly oriented pyrolytic graphite (HOPG) in specific patterns: when adsorbed from a solution of low concentration it forms stretched, isolated and sparsely distributed chains, while upon adsorption from a solution of higher concentration, it forms an interconnected network of multilayer features. The amount and topography of the adsorbed CMC affect the electrical properties as well as the wettability of the polymer-modified HOPG surface. Adsorption of CMC onto the HOPG surface causes the zeta potential to be more negative and the modified surface becomes more hydrophilic. This increase in both the absolute value of zeta potential and the surface hydrophilicity originates from the carboxymethyl groups of the CMC polymer. The effect of the adsorbed polymer layer on wetting film drainage and bubble-surface/particle attachment was determined using high speed video microscopy to monitor single bubble-surface collision, and single bubble Hallimond tube flotation experiments. The time of wetting film drainage and the time of three-phase contact line spreading gets significantly longer for polymer-modified HOPG surfaces, indicating that the film rupture and three-phase contact line expansion were inhibited by the presence of polymer. The effect of longer drainage times and slower dewetting correlated with reduced flotation recovery. The molecular kinetic (MK) model was used to quantify the effect of the polymer on dewetting dynamics, and showed an increase in the jump frequency for the polymer adsorbed at the higher concentration.

Bubble Attachment to Cellulose and Silica Surfaces of Varied Surface Energies: Wetting Transition and Implications in Foam Forming

“…26,36,37,39−41 However, there are few studies in which bubble interaction with biopolymers has been addressed. 38,40,41 In general, bubbles readily form a three-phase contact with hydrophobic particles but repel hydrophilic particles, and adsorption of surfactants and polymers can fully reverse this interaction. 26,41 Therefore, it is also important to study the connection between the bubble contact angle and surface tension of the system and model these phenomena.…”

“…Bubble attachment and detachment on (from) solid mineral particles are important for the recovery of collected minerals in froth flotation, , and the mechanisms underlying bubble–particle interactions have been studied comprehensively. − The stability of the wetting film between bubbles and particles dictates whether the bubble forms a three-phase contact with the surface. This stability depends greatly on the particle hydrophobicity, charge, and surface tension. , In froth flotation, also the kinetics of bubble collision with mineral particles is highly important and is usually studied using simple bubble–particle collision systems. ,, The collision kinetics has been studied for several mineral surfaces, such as mica, quartz, Teflon, graphite, and molybdenite. ,,,− However, there are few studies in which bubble interaction with biopolymers has been addressed. ,, …”

Adsorption of Carboxymethyl Cellulose onto Titania Particle Films Studied with in Situ IR Spectroscopic Analysis

“…In solution it obtains a random coil conformation; the extension of the coil depends on the ionic strength and pH . Semiflexible polyelectrolytes form predominantly two-dimensional adsorbed layers, attaching via longer quasi-planar trains. ,, The polymers can form lamellar or net-like structures depending on the screening and the intermolecular attractive interactions. − …”

Incorporation and antimicrobial activity of nisin Z within carrageenan/chitosan multilayers

“…AFM is a powerful technique providing information about the structure of adsorbed polymer in sub-monolayers 64,65 as well as topography of polymer films 66 in a liquid environment. PEM thickness and topography were determined using a Bruker Multimode 8 AFM with a Nanoscope V controller (Bruker, USA) which was located on an anti-vibration table (Vision IsoStation, Newport, USA).…”