A how-to approach for estimation of surface/Stern potentials considering ionic size and polarization

The Analyst ◽  
2015 ◽  
Vol 140 (21) ◽  
pp. 7217-7224 ◽  
Author(s):  
Xinmin Liu ◽  
Feinan Hu ◽  
Wuquan Ding ◽  
Rui Tian ◽  
Rui Li ◽  
...  

Based on the effects of ionic volume in Stern layer and polarization in diffuse layer, the relationship between surface potential and Stern potential is quantified.

Sensors ◽  
2021 ◽  
Vol 21 (13) ◽  
pp. 4397
Author(s):  
Kazuya Kikunaga

A mixture of positive and negative static charges exists in the same plane on an insulator surface, and this can cause production quality problems at manufacturing sites. This study developed a system with a vibration array sensor to rapidly measure the surface potential distribution of an object in a non-contact and non-destructive manner and with a high spatial resolution of 1 mm. The measurement accuracy differed greatly depending on the scanning speed of the array sensor, and an optimum scanning speed of 10 mm/s enabled rapid measurements (within <3 s) of the surface potential distribution of a charged insulator (area of 30 mm × 30 mm) with an accuracy of 15%. The relationship between charge and dust on the surface was clarified to easily visualize the uneven static charges present on it and thereby eliminate static electricity.


1990 ◽  
Vol 04 (03) ◽  
pp. 201-209
Author(s):  
A. GIEROSZYŃSKI

It was found that OSEE kinetics from electron bombarded cryosolidified NaCl solution, depend on electric charging of the sample surface. It was shown that from the relationship between the maximum surface potential and the parameters of OSEE kinetic, intensities of electric fields in the emitter layer could be estimated. It is supposed that nonhomogeneous electric fields existing in the emitter surface region, influence the emission levels responsible for the course of OSEE kinetics.


2008 ◽  
Vol 8 (6) ◽  
pp. 2971-2978 ◽  
Author(s):  
Tabitha Ku ◽  
Simardeep Gill ◽  
Raimar Löbenberg ◽  
Shirzad Azarmi ◽  
Wilson Roa ◽  
...  

The relationship between a model pulmonary surfactant system and various sized nanoparticles was investigated in this study. Diplamitoylphosphatidylcholine (DPPC) is the main lipid constituent of lung surfactant and has the ability to reach very high surface pressures (around 70 mN/m) upon compression. Due to these properties it was used as a model to simulate the lung surfactant film in vitro. The first objective of this study was to investigate the relationship between DPPC and various sized nanoparticles within the subphase through surface pressure—area isotherms. The second objective was to measure the surface potential of the different preparations (conducted on a mini-Langmuir trough) and to determine if an optimal nanoparticle size exists possessing a greater affinity for the DPPC film compared to other sizes. The results from the pressure area isotherms indicate that the interaction between DPPC and the nanoparticles is stable and that the 235 nm particles may represent an optimal size. Furthermore, the results from the surface potential experiments confirm that an interaction of the nanoparticles with the monolayer exists as indicated by surface-pressure area isotherms. Any even moderate interaction between nanoparticles and lung surfactant film might reduce or increase the surface potential of the surfactant film, and this might impact the deposition of the nanoparticles or other ligands which may be positively or negatively charged drugs within the surfactant film. Thus changes in surface potential due to nanoparticle interactions have to be taken into account for future drug targeting studies using nano-sized drug carriers.


2021 ◽  
Vol 5 (4) ◽  
pp. 47
Author(s):  
Karolina Kędra ◽  
Marzena Łazarczyk ◽  
Tajana Begović ◽  
Danijel Namjesnik ◽  
Karolina Lament ◽  
...  

Organic matter (OM) interactions with minerals are essential in OM preservation against decomposition in the environment. Here, by combining potentiometric and electrophoretic measurements, we probed the mode of coordination and the role of pH-dependent electrostatic interactions between organic acids and an iron oxide surface. Specifically, we show that malonate ions adsorbed to a hematite surface in a wide pH window between 3 and 8.7 (point of zero charge). The mode of interactions varied with this pH range and depended on the acid and surface acidity constants. In the acidic environment, hematite surface potential was highly positive (+47 mV, pH 3). At pH < 4 malonate adsorption reduced the surface potential (+30 mV at pH 3) but had a negligible effect on the diffuse layer potential, consistent with the inner-sphere malonate complexation. Here, the specific and electrostatic interactions were responsible for the malonate partial dehydration and surface accumulation. These interactions weakened with an increasing pH and near PZC, the hematite surface charge was neutral on average. Adsorbed malonates started to desorb from the surface with less pronounced accumulation in the diffuse layer, which was reflected in zeta potential values. The transition between specific and non-specific sorption regimes was smooth, suggesting the coexistence of the inner- and outer-sphere complexes with a relative ratio that varied with pH.


Author(s):  
Xinmin Liu ◽  
Rui Tian ◽  
Rui Li ◽  
Wuquan Ding ◽  
Hang Li ◽  
...  

The Gouy–Chapman surface potential is a key parameter for many interfacial phenomena in physical, chemical and biological systems. Existing theoretical approaches allow the determination of the surface potential at a solid–liquid interface only in single electrolyte solutions; however, mixed electrolytes are often encountered in practical applications. The development of a theoretical approach for the determination of the surface potential in mixed electrolyte solutions is therefore a desirable goal. In this study, this important issue was resolved for the first time. Based on the analytical solutions of the nonlinear Poisson–Boltzmann equation in different mixed electrolyte solutions, corresponding mathematical relationships were developed between the surface potential and the mean ionic concentration in the diffuse layer. As the mean ionic concentration in the diffuse layer can be easily determined, the surface potential could be calculated using the newly derived equations. The effects of electrolyte composition on the surface potential were theoretically quantified in the new equations, while only counterionic type was taken into account for mixed electrolyte solutions in the current studies.


2020 ◽  
Author(s):  
Miftah Hidayat ◽  
Jan Vinogradov ◽  
Stefan Iglauer ◽  
Mohammad Sarmadivaleh

&lt;p&gt;Electrochemical interactions of calcite with brines in natural subsurface settings have received ample attention in the last decades due to the broad range of their applications. These interactions can be described by an electrical property termed the zeta potential. Many numerical simulation studies using surface complexation modelling (SCM) have been performed to investigate the relationship between the zeta potential and a wide range of salinities and complex brine compositions. Although most of the simulated results, especially in low salinity conditions, successfully match the experimentally measured zeta potential, the simulated zeta potential for high salinity conditions is still poorly understood.&lt;/p&gt;&lt;p&gt;In this study, we present a new approach of SCM to simulate the zeta potential by considering the actual molecular-scale phenomena at the calcite-brine interface. Unlike previous SCM studies, our model considers the hydrated diameter of ions as the distance of approach, which depends on salinity. We also consider the permittivity of the Stern layer as a function of salinity, which is consistent with previous unrelated studies. We calculate the capacitance for each salinity based on the relationship between the hydrated diameter of ions and the permittivity of the Stern layer. Moreover, all calcite-brine surface reactions are described by new equilibrium constants independent of salinity and composition of brines.&lt;/p&gt;&lt;p&gt;Our results show that the simulated zeta potential which is obtained from our SCM at a broad range of salinities is successfully matched with the published experimental data for two different carbonate rock samples as long as the salinity dependence of the hydration diameter and electrical permittivity is accounted for. We find that the potential determining ions (Ca&lt;sup&gt;2+&lt;/sup&gt;, Mg&lt;sup&gt;2+&lt;/sup&gt;, SO&lt;sub&gt;4&lt;/sub&gt;&lt;sup&gt;2-&lt;/sup&gt;, HCO&lt;sub&gt;3&lt;/sub&gt;&lt;sup&gt;-&lt;/sup&gt;,CO&lt;sub&gt;3&lt;/sub&gt;&lt;sup&gt;2-&lt;/sup&gt;) play a dominating role compared to the indifferent ions (Na&lt;sup&gt;+&lt;/sup&gt;, Cl&lt;sup&gt;-&lt;/sup&gt;) in the calcite-brine surface reactions. The Implications of our findings are significant for wettability evaluation, characterisation of shallow and deep aquifers and CO&lt;sub&gt;2&lt;/sub&gt; geological sequestration.&lt;/p&gt;


Our knowledge of the structure of the electrical double layer at the interface between a solid and a liquid is so indefinite that it is difficult to give a precise definition or to make an exact measurement of electrokinetic potential. In the liquid in the immediate vicinity of the solid surface, there will be an excess of ions of opposite charge to that on the surface, forming an electrical double layer which is approximately a molecular diameter in thickness. All the potential drop, however, is not confined to this first double layer ; the excess ions in the solution are not rigidly held to the surface, they are able to break away and to form a diffuse layer which extends some distance into the solution. Experience has shown that gentle stirring of the solution can influence the distribution of these ions, and it is probable that the diffuse layer extends as far as 10 -5 to 10 -4 cm. from the solid surface. It is this diffuse layer of more or less loosely held ions which is responsible for the electrokinetic properties of liquids in contact with solid surfaces. No exact relation has been established connecting the diffuse, or electrokinetic potential, with the total potential drop between a solid and a liquid. Usually they are of the same sign, but there is evidence that the potential drop across the diffuse layer can even be opposite in sign from the main potential, indicating a twofold double layer. The presence of polar molecules adsorbed at the interface may have a profound effect on the distribution of the diffuse layer without sensibly affecting the total potential difference. Further work on the relationship between these quantities would be valuable.


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