Adsorption Of Gelatin Research Articles

Simultaneous adsorption of gelatin and long-chain amphiphiles at solid-water interface

Simultaneous adsorption of gelatin and anionic or cationic long-chain amphiphiles from the solution to the surface of alumina has been studied as function of protein concentration, pH, and temperature of the medium. The long-chain amphiphiles used are cetyltrimethyl ammonium bromide (CTAB), myristyltrimethyl ammonium bromide (MTAB), dodecyltrimethyl ammonium bromide (DTAB), cetylpyridinium bromide (CPB), and sodium dodecyl sulfate (SDS). At a fixed total concentration of the surfactant ( C s 1), adsorption of gelatin at the alumina-water interface increases with increase of gelatin concentration ( C p) in the bulk solution until a constant value Γ p m is reached. Γ p m changes considerably with increase of net charge of gelatin and with increase of temperature. The effects of hydrocarbon chain length and the nature of the head groups of the surfactant on Γ p m have also been critically examined. The adsorption isotherms of bovine serum albumin (BSA) and gelatin at hydrophobic graphite-water interface have been compared at different pH in presence and absence of long-chain amphiphiles. The number of moles of amphiphile ( Γ s a) associated per mole of gelatin at the interface and that ( Γ s eq) of the same surfactant bound per mole of gelatin in the bulk phase have been compared. The binding of surfactant to the protein at the interface is massive and cooperative at a critical bulk concentration of the surfactant in solution. Free energy changes of amphiphile-protein interaction in the interface have been calculated using the Tanford equation. The standard free energies for the transfer of protein from bulk solution to the alumina-water interface have been calculated using appropriate thermodynamic relations.

Influence of gelatin on the precipitation of amorphous calcium phosphate

The influence of gelatin on the formation, stability and transformation of amorphous calcium phosphate, ACP, at 298 K and initial pH 7.4 was investigated. Precipitation of ACP was brought about from equimolar solutions (3×10 −3 mol dm −3) of calcium chloride and sodium phosphate while the concentration of gelatin varied from 0.0001 to 1.12 g dm −3. The interaction between gelatin and ACP was characterized by particle electrophoretic mobility, pH and turbidity measurements. The ACP electrophoretic mobility during the precipitation in the presence of gelatin indicated gelatin adsorption onto ACP as the dominating interaction mode. By adsorbing on the surface of primary particles gelatin slows down or even prevents ACP aggregation thus stabilizing its colloidal state. Besides, the presence of gelatin promotes the transformation of ACP into a crystalline phase.

Study of the Desorption of Gelatin on Silver Bromide by Means of Sodium Polystyrene Sulphonate

AbstractThe physical-chemical interactions between sodium polystyrene sulphonate (PSS), gelatin and a silver bromide sol are studied under different reaction conditions (pH, ionic strength, concentration of the reaction partners) by means of several experimental techniques: acidimctry, viscosimetry, micro-electrophoresis, calorimetry and measurement of the hydrodynamic adsorption layer thickness.The gelatin—PSS interaction in solution is mainly ruled by electrostatic attraction between protonated cationic sites of the gelatin and the sulphonate groups of PSS. This interaction results in a hindrance or at least in a substantially reduction of the adsorption of gelatin on a negatively charged silver bromide surface. The mechanism is not based on a surface replacement of gelatin by PSS but on the reaction in solution of PSS with gelatin, competitive with the adsorption of gelatin.

Core treatment for improving microencapsulability in simple gelatin coacervation method.

In microencapsulation by way of simple coacervation by gelatin, some core materials are encapsulated easily, whilst others are difficult to encapsulate or show an encapsulability dependent on the coacervation-inducing agent. The treatment of core materials to improve encapsulability was studied. It was found that core particle encapsulability can be improved by recrystallization from aqueous solution of an ionic polymer. Electrophoresis, microscopical observation and pH dependency of encapsulability of recrystallized cores revealed that the electrostatic attractive force between gelatin molecules in solution and a polymer attached to the core particle cause gelatin adsorption on the core surface to result in a great improvement in encapsulability.

Factors affecting microencapsulability in simple gelatin coacervation method.

Microencapsulation by way of simple coacervation by gelatin was examined. Five kinds of core material and six kinds of coacervation-inducing agent (CIA) were chosen and the encapsulability of each combination was studied. Some core materials are easily encapsulated, others are difficult to encapsulate, and some show a dependency of encapsulability on the CIA. Electrophoresis and gelatin adsorption studies revealed that encapsulation by way of simple coacervation by gelatin is caused by the affinity between core and coacervate resulting from gelatin adsorption on the core surface. These studies further revealed that cores onto which a large amount of gelatin has been adsorbed before coacervation can be encapsulated.

Preparation, Optimization, and Cathodoluminescent Properties of a Line Emission Penetration Phosphor

A multicolor line emission penetration phosphor, suitable for use in high brightness CRT's, has been developed. The system consists of multilayered powder particles containing a green‐emitting core, a nonluminescent middle layer, and a cover coating of small (∼1 μm) red‐emitting particles. Preparation of the phosphor involves two basic steps: (i) the controlled oxidation of particles to produce an onionskin surface layer of and (ii) coating of the core particles with the small particles using a gelatin adsorption technique. Optimization with respect to brightness and color range yielded a system that was significantly brighter than previously developed line emission penetration phosphors while providing a comparable color range. Further, large size core particles were found to improve the phosphor system performance due to a saturation of the red component brightness at high working voltages. The paper discusses details of the preparation, optimization, and cathodoluminescent properties of this system.

An Ellipsometric Study of the Adsorption of Gelatin on Silver Bromide

AbstractOptically-polished surfaces of silver bromide were examined by ellipsometry to establish their optical properties. The adsorption of gelatin onto the surfaces from an aqueous solution at 40° C was then followed ellipsometrically. Measurements were carried out as a function of time and as a function of pH at pBr 3. From the measurements, it was possible to obtain the adsorption excess of the gelatin at the surface, the optical thickness of the adsorbed layer and the concentration of gelatin in the adsorbed layer. The optical thickness of the adsorbed layer was found to vary significantly with pH and to reach a maximum value of ca. 400 A at the isoelectric point of the gelatin.

Researches on the Nature of the Functional Groups Involved in the Adsorption of Gelatin on AgBr.

Adsorption isotherms for normal and modified gelatin on silver bromide at various pH were obtained. The amount of gelatin adsorbed is in relation with the pH, but the variations appear to be determined not only by electrostatic interactions, but also by functional active groups that play an important part in the adsorption process of gelatin. The importance of - NH3 and -COOH groups is so demonstrated.

The Adsorption of Gelatin on Silver Bromide

AbstractThe adsorption heat of gelatin on AgBr was determined calorimetrically in function of the pH for gelatins with high and low isoelectric point (IEP). The adsorption heat increases for pH-values lower than the IEP and remains constant for the higher pH-values. The differences in adsorption heat are also revealed by competitive adsorption with dyes. The amount of adsorbed gelatin is also strongly pH-dependent. The results obtained completely confirm the hypothesis of Pouradier and Roman concerning the structure of the adsorbed gelatin layer; the first molecules are spread over the AgBr surface so as to form a monolayer. If more gelatin is added a reorganisation of the adsorbed molecules occurs. Segments of one definite molecule are replaced by segments of another one. In this way the quantity of gelatin adsorbed can be multiplied.

The Adsorption of Gelatin to Silver Bromide Microcrystals

A strong bond formation between the aspartic acid residues of gelatin molecule and the silver bromide surface in various conditions gives good reason to believe that these residues are the groups by means of which the gelatin adsorbs to the silver bromide; this must be a true chemisorption. Such assumption allowed one (a) to calculate the length of a segment (ioop) of a single-chain gelatin molecule between the possible points of adsorption and (b) to draw some conclusions on the thickness and structure of gelatin adsorption layer on the silver bromide microcrystals. These results are in good agreement with the data of other authors.

Adsorption of Gelatin to Silver Bron1ide

Adsorption and desorption isotherms for gelatin on silver bromide at both pH 6 5 and 3 5 were obtained. At pH 6 5 the adsorption was higher than at pH 3 5 but a proportion of the gelatin was desorbable. There was no detectable desorption at pH 3-5. In addition the effect of adsorbed gelatin on the fixation time of silver bromide sols was examined. The decrease in fixation time observed with added gelatin was most marked at pH values below the isoelectric point, and at the lower temperatures examined. It is concluded that the net charge on the gelatin molecule in relation to the charge on the surface plays an important part in the configuration of the adsorbed layer although it has a comparatively small effect on the total amount of gelatin adsorbed. When the charge is the same as that on the surface, the proportion of adsorbed segments is small and the rate of desorption becomes significant

Effects of time, surface area, pH and some ions on protein adsorption by bovine enamel

Some aspects of protein adsorption were studied by measuring nitrogen uptake on 100–200 mesh bovine enamel. Using casein, it was found that after initial rapid adsorption uptake continued at a slowing rate for 60 min. Protein adsorption increased with decreasing size of enamel powder, with mesh size below 270 taking up more than 7 times that of 20–40 mesh particles. Less casein, bovine serum gamma globulin and gelatin were adsorbed from 0.01M phosphate buffer as the pH was raised from pH 6 to pH 8. Comparisons of the effect of various ions showed that potassium phosphate and sodium citrate interfered with adsorption of gelatin, while calcium chloride gave evidence of increasing it. Sodium fluoride gave ambiguous results.

The Adsorption of Gelatin to a Silver Powder

AbstractA silver powder was prepared by borohydride reduction of freshly precipitated silver bromide. Its surface area was estimated by dye adsorption to be 1·6m2g.–1. The adsorption of gelatin from solution at pH6 was studied and isotherms were derived at 25° and 35°C. The results showed features typical of polymer adsorption generally. For gelatin concentrations below about 0·25 per cent, adsorption was not detectably dependent on temperature. Above this level, adsorption is greater at 25°, which is attributed to the effect of gelling forces in the adsorbed layer. A Langmuir plot of the 35° isotherm was approximately linear. The adsorbed gelatin could not be desorbed. The last fact does not necessarily forbid the application of equilibrium thermodynamic theory, since the apparent irreversibility may reside solely in the need to desorb many polymer segments simultaneously. Heat of adsorption was investigated with the aid of a microcalorimeter. With a 0·2 per cent gelatin solution, a slow heat evolution w...

The Adsorption of Gelatin to a Silver Bromide Sol

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTThe Adsorption of Gelatin to a Silver Bromide SolH. G. Curme and C. C. NataleCite this: J. Phys. Chem. 1964, 68, 10, 3009–3016Publication Date (Print):October 1, 1964Publication History Published online1 May 2002Published inissue 1 October 1964https://doi.org/10.1021/j100792a047RIGHTS & PERMISSIONSArticle Views76Altmetric-Citations44LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (871 KB) Get e-Alerts

The Adsorption of Gelatin by Suspended Solids and the Mechanism of Flocculation

AbstractPrevious work on the adsorption of gelatin from solution onto the surface of suspended solids is reviewed in the light of recent theoretical and practical investigations on the adsorption of synthetic high polymers. The sensitization and protection of gold sols, and the mechanism of flocculation of suspensions with gelatin is discussed.

The Adsorption of Gelatin to Developed Silver and the Role of Gelatin in Development

The adsorption of gelatin to developed silver is demonstrated and semi-log isotherms are constructed at two temperatures in the presence and absence of developer components. Analysis of the isotherms suggests that the adsorption is weak (physicol) but this is contradicted by its observed irreversibility. The induction period and apparent energy of activation of development in the liquid system studied are shown to increase with gelatin concentration.The effect of a cationic wetting agent on adsorption and development is described. The specific gravity of silver developed under various conditions is recorded.The possibility is suggested that the firmly bound layer of gelatin on emulsion groins, creates a "thermal" barrier as a result of a difference (not proven) in the heat of adsorptions to silver hol1de and silver. Loosely bound gelatin is believed to form a conventional negative charge barrier.

THE EFFECT OF ADDITION AGENTS ON CATHODE POLARIZATION DURING ELECTRODEPOSITION OF COPPER AT SINGLE CRYSTAL COPPER CATHODES

The polarization–time relations for the initial (Pi), maximum (Pmax), and pseudo-steady-state (Ps) polarizations on copper single crystals in the absence and presence of gelatin and gelatin plus chloride ion were found to depend upon crystal orientation. The Pi and Pmax in the absence of gelatin, the Pi in its presence, and the static potentials were all similarly related to the reticular density. The Pi increased, and the time to maximum polarization (tmax) decreased, with increase of current density; the relations between these quantities showed marked differences for the different crystals. The variation with reticular density of Pi and Pmax in the absence of addition agents and of Pi in its presence probably represents differences in activation overpotential at the various crystal faces. The adsorption of gelatin on different crystal faces was also found to be markedly different. Polarization in the presence of gelatin was decreased by small amounts of chloride ion; a linear relation for all the crystals used was obtained by plotting the increase in polarization caused by gelatin against the decrease caused by 2 mgm./liter chloride ion in the presence of gelatin. In the absence of addition agent, change of acid concentration from 50 to 200 gm./liter had no effect on Pi and addition of chloride ion had no effect on Ps at single crystal cathodes.

The Adsorption of Gelatin to Silver Bromide

Experimental data are presented illustrating a specific case of amphipathic adsorption, namely, of gelatin to silver bromide. In this there is mutual coagulation of the silver hydrosol and protein, followed by peptization in excess of dissolved protein. The phenomena in their relation to the isoelectric point of the protein and the pH of the solution are interpreted in terms of a basically duplex polar: non-polar structure in proteins, and of a resonance factor, involving both adsorbent and adsorbate, in similar cases.

CATHODE SURFACE CHANGES IN THE PRESENCE OF GELATIN DURING ELECTRODEPOSITION OF COPPER

Measurements of the cathode polarization during electrodeposition of copper from acid copper sulphate solutions indicate that introduction of gelatin into the electrolyte decreases the area of the cathode available for deposition, or active area, owing to adsorption of gelatin on the active centres. This decrease in area causes an increase in the true current density, with a resulting increase in cathode polarization, the former being assumed the main factor in causing an increase in the rate of nuclear formation and decrease in grain size.

THE ADSORPTION OF GELATIN BY COLLODION MEMBRANES

An experimental study has been made of the adsorption of gelatin from solution at 37 degrees C. by collodion membranes. In the case of membranes of high permeability, very high concentrations of gelatin were required to produce maximum adsorption, and the maximum amounts adsorbed were independent of the pH values of the solutions over the range 3.8 to 4.8. With membranes of low permeability, maximum adsorption was reached at lower gelatin concentrations, and the maximum amounts adsorbed varied with the pH, being lower on either side of the isoelectric point, over the range 3.8 to 6.6. The addition of salt in such experiments raised the maximum amount adsorbed to a value equal to that obtained with solutions at the isoelectric point in the absence of salt. These experiments can be explained by, and seem to lend support to, the theory proposed by Loeb and further developed by Kunitz concerning the effects of pH and salt on the size of gelatin particles in solution.