Interfacial Dilational Properties Research Articles

Methodological approach to characterize the interfacial and foaming properties of carbonated beverages

The adjustment and control of specific product characteristics, e.g., foaming behavior of carbonated beverages, requires an understanding of influencing factors along with reliable analytical methods. However, due to the overlay of different phenomena, i.e., release of CO2 and action of surface-active molecules contained in such beverages, it is difficult to assess their respective contribution to foam appearance and stability. This study aimed at evaluating a new methodological approach to investigate the interfacial and foaming properties of carbonated beverages. Using beer as an example, it was attempted to establish a correlation between interfacial properties and foaming behavior. To ensure a comprehensive dataset, surface tension, interfacial dilatational rheology, and foaming properties including foam structural characteristics of six different German beers of three different types (i.e., Pils, wheat beer and Koelsch), which are known to exhibit distinct foaming behavior, were measured. While foams prepared with CO2 as sparging gas did not show any differences in foam aging, use of air for foaming enabled differentiation based on beer type. Differences observed in foam structural characteristics and stability could not be related to dynamic surface tension but might be linked to interfacial dilatational properties. Overall, the presented multiscale approach can be seen as promising concept for further experimental studies on carbonated beverages.

Dilational rheological properties of extended anionic surfactants at decane-water interface

The dynamic interfacial dilational properties of extended surfactants octadecyl-(polypropylene oxide)m-(polyethylene oxide)n-carboxylic sodium (C18POmEOnC) with different numbers of polypropylene oxide (PO) and polyethylene oxide (EO) groups at the decane–water interface were investigated by means of oscillating drop method. The influences of interface ageing time, dilational frequency, bulk concentration and interfacial pressure on the dilational properties were investigated. The experimental results demonstrate that, at low concentrations, the adsorption film is predominantly influenced by diffusion exchange, while intermolecular interactions at the interface play a more significant role at high concentrations. Beyond the critical micelle concentration (CMC), the primary relaxation process in the adsorption film is driven by the formation of micellar structures. Additionally, the weak hydrophobic PO groups exhibit compressibility and extensibility, facilitating the formation of spring-like helical structures at the decane–water interface. As a result, the dilational modulus increases and the phase angle decreases in low concentration with the increase of PO number. With increasing concentration, the weak hydrophilic EO chains gradually transition from a partially flat state to an upright orientation toward the aqueous phase, forming sublayer structures through polar interactions. At this stage, the increase in EO group chain length has a more pronounced impact on the elastic modulus compared to PO groups. These experimental findings suggest the existence of a mechanistic model for the extended surfactant adsorption films.

Modulation of Lipid Digestion by Nanoarchitectonics of Complex Interfacial Structures with Tween 80 and Lecithin.

In recent years, there has been a growing interest in regulating lipid digestion through the construction of various interfacial structures. In the present work, a series of complex interfacial structures were designed by combining Tween 80 in the aqueous phase and lecithin in the oil phase at different concentration ratios. The emulsification properties, the roles in regulating lipid digestion, and the interfacial dilatational rheological properties of the composite emulsifying systems were characterized. The results showed that the combination of Tween 80 and lecithin at different ratios could effectively modulate the rate of lipid digestion. The polyoxyethylene chains of Tween 80 formed a network, that provided a spatial obstacle for the adsorption of bile salts and lipases. Thus, Tween 80 significantly delayed the lipid digestion. The introduction of lecithin gradually replaced Tween 80 molecules at the interface, thus providing space for the adsorption of bile salts and lipases. In addition, as the ratio of lecithin concentration to Tween 80 increased, lecithin gradually became the dominant factor in the interfacial properties. As a result, the rate of lipid digestion was accelerated. Therefore, by compounding different ratios of lecithin and Tween 80, a series of emulsions with different lipid digestion rates were obtained. This research provides a basis for rationally designing food emulsions according to specific needs.

The Interfacial Dilational Rheology Properties of Betaine Solutions: Effect of Anionic Surfactant and Polymer.

Interfacial dilational rheology is one of the important means to explore the interfacial properties of adsorption films. In this paper, the interfacial rheological properties of the mixed system of sulfobetaine ASB with a linear alkyl group and two anionic surfactants, petroleum sulfonate (PS) and alkyl polyoxyethylene carboxylate (AEC), were investigated by interfacial dilational rheology. The effect of the introduction of polymer hydrophobically modified polyacrylamide (HMPAM) on the interfacial properties of the mixed system was analyzed. In this experiment, the surfactant solution was used as the external phase and n-decane was used as the internal phase. A periodic sinusoidal disturbance of 0.1 Hz was applied to the n-decane droplets, and the changes of parameters such as droplet interfacial tension and interfacial area were monitored in real time with the help of a computer. The results show that the betaine ASB molecule responds to the dilation and compression of the interface through the change of ion head orientation, while the feedback behavior of petroleum sulfonate PS and AEC molecules embedded with oxygen vinyl groups in the molecule is diffusion and exchange between the interface and the bulk phase. Therefore, the interface film formed by ASB alone is higher, and the film formed by PS and AEC molecules alone is relatively lower. After adding two kinds of anionic surfactants to the betaine system, the ionic head of PS or AEC molecules will be attached to the positive center of the hydrophilic group of ASB molecules by electrostatic attraction and no longer adsorb and desorb with the interface deformation. The interfacial rheological properties of the compound system are still dominated by betaine, with higher dilational modulus and lower phase angle. When a small amount of HMPAM is added, or the content of hydrophobic monomer AMPS in the bulk phase is low, the intermolecular interaction at the interface is enhanced, the slow relaxation process is intensified, and the interfacial film strength is increased. As the content of AMPS further increases, hydrophobic blocks and surfactant molecules will form interfacial aggregates similar to mixed micelles at the oil-water interface, which will regulate the properties of the film by affecting the adsorption of surfactants at the interface. As long as the interfacial tension is the same, the properties of the interfacial film are the same. Based on the colloid interface science and the background of enhanced oil recovery, this study provides a reference for the field application of chemical flooding formulations.

Influences of asphaltene subfractions with different polarities on hydrate growth at water/oil interface

As a kind of typical natural surface-active substance, asphaltenes can not only lead to deposition and plugging accidents, but also affect the formation and slurry flow of hydrate during deep-sea oil and gas transportation process. This paper investigates the polarity effects of the asphaltene subfractions on the growth process of hydrate particles at oil–water interface. First of all, four asphaltene subfractions with different polarities were extracted by the solvent precipitation method. Then, the dynamic interfacial tension and dilational viscoelastic properties were measured to characterize the oil–water interfacial films adsorbed with the different asphaltene subfractions. Following that, the hydrate growth experiment was carried out using a self-designed atmospheric visualization unit. Specifically, the transformation process of a single droplet into a hydrate particle in oil phase containing asphaltenes was studied to determine the influence of asphaltene subfractions on hydrate growth. The change degree of particle morphology and the growth rate of hydrate shells were used as two analysis indexes. The results show that the change degree of particle morphology and the growth rate of hydrate shells were both affected by the dispersion state and interfacial adsorption amount of the asphaltene subfractions. Under the combined action of migration and surface covering, the asphaltene subfractions have different effects on hydrate growth process at various concentrations. At the concentration of 0.01 mg/g and 0.1 mg/g, a looser interfacial adsorption layer will result in a large effective interfacial area, i.e., a weaker mass transfer hindrance. At this time, the structural strength of the interfacial film is low. At the concentration of 0.2 mg/g, however, the transformation rate of the hydrate shells is accelerated owing to the trapped oil phase, so the structural strength of the interfacial film is enhanced. Therefore, with the increase of the asphaltene concentration, the hydrate particles are easier to maintain their original state.

Efficient pesticide formulation and regulation mechanism for improving the deposition of droplets on the leaves of rice (Oryza sativa L.).

The effective deposition of pesticide droplets on the target leaf surface is critical for improving the utilization of pesticides. We proposed a new way to enhance the droplet deposition on the target leaf surface by changing the properties of pesticide formulation, and this formulation can be sprayed directly or at a low dilution. In addition, it is a simple method to select a suitable concentration and formulation by evaluating the interfacial dilational rheological properties of pesticide droplets. The wetting behavior of two types of pesticide formulations prepared by oil-based solvent on the rice leaf surface was investigated based on the surface free energy, surface tension, contact angle, adhesion tension, and adhesion work. The interfacial dilational rheological properties of different pesticide solutions were measured as a function of concentration. This study clearly demonstrates the fact that water-in-oil emulsion has a better wettability than oil-in-water emulsion, especially with the increase of the concentration of the solution, the droplets can be wetted and spread faster on the leaves. Compared with vegetable oil (methyl oleate), mineral oil (solvent oil No. 200) has smaller dilational modulus and surface tension, showing excellent wetting properties. The water-in-oil emulsion prepared with solvent oil No. 200 has the smallest dilational modulus, and the spray droplets spread rapidly to the maximum wetting area on the rice leaves, which can be used in an ultra-low volume spray. The results provide new insights into how to increase the deposition of droplets on superhydrophobic leaf surfaces by screening formulations and concentrations. © 2021 Society of Chemical Industry.

Interfacial dilatational and emulsifying properties of ultrasound-treated pea protein

In this study, the structural, interfacial, and emulsifying properties of high-intensity ultrasound (HUS)-treated pea protein isolate (PPIUS) were investigated. HUS at 50% amplitude and 57–60 W·cm−2 for 5 min markedly improved protein solubility (by 132%), surface hydrophobicity (by 173%), and reduced particle size (by 52%). These physicochemical changes in PPIUS led to more rapid protein adsorption at the oil–water interface, improved emulsifying activity (by 18–27%) and capacity (by 11%), and enhanced emulsion physical stability. The multilayer nature, albeit less elastic, of the interfacial membrane formed by PPIUS when compared to control protein (PPIC), based on dilatational testing, contributed to the above results. Moreover, PPIUS-stabilized emulsions exhibited a tendency of being less susceptible to lipid oxidation during storage. Thus, structure-modifying HUS may be a valuable processing technology for the manufacture of pea protein-based emulsion foods.

Dilatational rheology of water-in-diesel fuel interfaces: effect of surfactant concentration and bulk-to-interface exchange.

Micrometer-sized water droplets dispersed in diesel fuel are stabilized by the fuel's surface-active additives, such as mono-olein and poly(isobutylene)succinimide (PIBSI), making the droplets challenging for coalescing filters to separate. Dynamic material properties found from interfacial rheology are known to influence the behavior of microscale droplets in coalescing filters. In this work, we study the interfacial dilatational properties of water-in-fuel interfaces laden with mono-olein and PIBSI, with a fuel phase of clay-treated ultra-low sulphur diesel (CT ULSD). First, the dynamic interfacial tension (IFT) is measured using pendant drop tensiometry, and a curvature-dependent form of the Ward and Tordai diffusion equation is applied for extracting the diffusivity of the surfactants. Additionally, Langmuir kinetics are applied to the dynamic IFT results to obtain the maximum surface concentration (Γ∞) and ratio of adsorption to desorption rate constants (κ). We then use a capillary pressure microtensiometer to measure the interfacial dilatational modulus, and further extract the characteristic frequency of surfactant exchange (ω0) by fitting a model assuming diffusive exchange between the interface and bulk. In this measurement, 50-100 μm diameter water droplets are pinned at the tip of a glass capillary in contact with the surfactant-containing fuel phase, and small amplitude capillary pressure oscillations over a range of frequencies from 0.45-20 rad s-1 are applied to the interface, inducing changes in interfacial tension and area to yield the dilatational modulus, E*(ω). Over the range of concentrations studied, the dilatational modulus of CT ULSD with either mono-olein or PIBSI increases with a decrease in bulk concentration and plateaus at the lowest concentrations of mono-olein. Characteristic frequency (ω0) values extracted from the fit are compared with those calculated using equilibrium surfactant parameters (κ and Γ∞) derived from pendant drop tensiometry, and good agreement is found between these values. Importantly, the results imply that diffusive exchange models based on the equilibrium relationships between surfactant concentration and interfacial tension can be used to infer the dynamic dilatational behavior of complex surfactant systems, such as the water-in-diesel fuel interfaces in this study.

Effect of pH on okara protein-carboxymethyl cellulose interactions in aqueous solution and at oil-water interface

The physicochemical and interfacial properties of Okara protein (OP) are susceptible to be affected by various factors. In this respect, the role of inter- and intramolecular interactions between OP and carboxymethyl cellulose (CMC) were explored by in situ experiments. OP/CMC aqueous mixtures, containing 1.0 wt% OP and 0–0.5 wt% CMC, were prepared at pH 7.0 and 4.0. Subsequently, their physicochemical properties, interactions, and interfacial adsorption were comparatively characterized. OP formed larger aggregates at lower pH as confirmed by the visual appearance. The addition of CMC reduced the surface hydrophobicity and increased viscosity of OP/CMC mixtures regardless of pH. CMC increased the hydrodynamic diameter of mixtures at pH 7.0, while it led to more negatively-charged complexes with decreasing size at pH 4.0. Noticeably, the results regarding the interfacial pressure, adsorption kinetics and interfacial dilatational viscoelastic properties presented three remarkable phenomena: Low concentrations of CMC hardly affected the initial interfacial performance of OP at pH 7.0, whereas the latter was greatly reduced at high CMC concentrations. Moreover, high CMC concentrations appropriately reinforced the interfacial performance of OP at pH 4.0.

Lignosulfonates in Crude Oil Processing: Interactions with Asphaltenes at the Oil/Water Interface and Screening of Potential Applications.

The goal of this article is to test the potential application of lignosulfonates (LSs) in crude oil production and processing. Three LS samples of varying hydrophobicity and average molecular weight were considered. First, the interfacial tension between brine and xylene and interfacial dilational rheology properties of LS samples were measured. It was found that the most surface-active LS sample has the lowest molecular weight in agreement with the results from the literature. In the presence of asphaltenes, all three LS samples were able to compete with asphaltenes, the most polar crude oil component, at the interface and form mixed LS–asphaltene interfaces. However, only the most surface-active LS sample among the three tested could fully desorb asphaltenes at the highest tested LS concentration (500 ppm). Second, three possible applications were screened. LSs were tested to prevent the formation of w/o crude oil emulsions or to break these. However, the opposite effect was observed, that is, stabilization of water-in-crude oil emulsions. The potential application of LS in produced water (PW) clarification was furthermore considered. The kinetics of PW clarification was found unaffected by the presence of LS, even at very high concentrations (1000 ppm). Finally, the potential of LS for enhanced oil recovery was assessed. The LS flood changed the surface wettability toward water wetness for one of the samples, yet LS injection did not recover additional oil beyond brine recovery. It was concluded that LS has interesting properties, such as the potential to compete with crude oil indigenous components at the oil/water interface. The stabilization action of LS was dominant over any destabilization effect, which led to the conclusion that LSs are more efficient for stabilizing emulsions rather than destabilizing.

Soy glycinin-soyasaponin mixtures at oil–water interface: Interfacial behavior and O/W emulsion stability

Soy glycinin (11S) was mixed with soyasaponin (Ssa) to elucidate the mechanism(s) involved in the stabilization of emulsions by mixed systems based on dynamic interfacial tension and dilatational rheology at the oil–water interface. The short/long-term properties of oil-in-water emulsions stabilized by 11S–Ssa mixtures included droplet-size distribution, droplet ζ-potential, microstructure, and Turbiscan stability index. The combination of Ssa (0.05%) with 11S significantly affected the interfacial dilatational and emulsion properties although the interfacial properties were still dominated by the protein. Higher concentrations (0.1% and 0.2%) of Ssa combined with 11S synergistically decreased the interfacial tension, which was attributed to the interaction between 11S and Ssa. Using high Ssa concentrations (0.25%–0.5%) enhanced the long-term stability of emulsions (in response to external deformations) after 42 d. These results will aid the basic understanding of protein–Ssa interfacial adsorption during emulsion formation and can help prepare natural food additives for designing emulsions.

Relationship between air-water interfacial dilational viscoelasticity and foam property in aqueous solutions of sodium alkylsulfates with different hydrocarbon chains

The influence of alkyl chain structures in sodium alkylsulfates (ASs) on their rheological properties was investigated in this study. Dilational viscoelasticity at the air-water interface, dynamic surface tension, and foam property were quantitatively evaluated in aqueous solutions of ASs with different hydrocarbon chains, and the relationship was systematically discussed. The experimental results show that the alkyl chain plays an important role in the interfacial dilational properties. For ASs with straight alkyl chains, AS with the longer alkyl chain showed the maximum value of the interfacial dilational viscoelasticity at the lower concentration. The longer the alkyl chain of AS was the larger the maximum value of the interfacial dilational viscoelasticity was. The frequency dependence of the interfacial dilational viscoelasticity was confirmed only in the range of high surfactant concentrations, suggesting that the interfacial relaxation process is mainly controlled by the diffusion of the surfactants. As for the relationship between interfacial dilational viscoelasticity and foam property, it was found that the maximum value of the interfacial dilational viscoelasticity was correlated with the foam stability under the conditions.

A simple and effective strategy to enhance the stability and solid-liquid interfacial interaction of an emulsion by the interfacial dilational rheological properties.

The development of an emulsion is an important challenge in many fields, such as agrochemicals, pharmaceutics, paints, cosmetics, inkjet printing, and food science. However, the traditional strategies that refer to the empirical value and complex secondary additives cannot reflect the influence of the structure, content, compound, and adsorption of emulsifiers. Here, we propose a simple and effective strategy to develop the emulsion, wherein the emulsifiers are chosen based on the dilational rheological properties of the interfacial films at the molecular level. The dilational rheological properties of polyoxyethylene (80) castor oil (EL-80), sorbitan monostearate (Span 60), and their emulsions were explored by the oscillating drop method. Based on the dilational rheological properties, the emulsions were prepared by the phase inversion emulsification technique. The results showed that the emulsion was stable and realized effective solid-liquid interfacial interaction, which was attributed to the large dilational modulus (intermolecular interaction) at the oil/water interface and loss modulus (molecular diffusion exchange) at the air/water interface. These factors reduced the Ostwald ripening and coalescence, and finally increased the spreading diameter. Additionally, the prochloraz 25% emulsion in water (EW) and difenoconazole 20% EW were developed to verify the feasibility of the strategy. Therefore, this research advances the understanding of an emulsion by interfacial dilational rheological properties, which can provide a simple and effective strategy to develop a stable emulsion and achieve an effective solid-liquid interfacial interaction of the emulsion.

Oil-water interfacial behavior of soy β-conglycinin–soyasaponin mixtures and their effect on emulsion stability

We investigated the dilatational rheology and dynamic interfacial tension of soy β-conglycinin (7S) and soyasaponin (Ssa) mixtures at the oil-water interface, followed by the formation and short/long-term stability of the subsequent emulsions to evaluate the mechanism(s) of stabilizing emulsions using a fixed concentration of 7S (0.5%) in all the samples. The presence of a low concentration of Ssa (0.05%) significantly affected the interfacial dilatational and emulsification properties although 7S dominated the interface. Higher concentrations of Ssa (0.1%–0.75%) showed synergistic effects on the changes in interfacial tension due to the interactions between 7S and Ssa. These effects were primarily attributed to the complexation of 7S with Ssa, thereby loosening the rigid conformation of the protein and unfolding 7S at the interface. Owing to the elasticity of the mixed adsorption layers, the interfacial 7S–7S and 7S-Ssa interactions were enhanced. The improved resilience to external deformations and interfacial behaviors of these mixed layers induced long-term stability (42 days) in these emulsions. These results provide a potential application for natural food additives in designing emulsions by modulating protein-saponin mixtures to induce long-term stability.

Studies of interfacial interactions between petroleum acids and associating polyacrylamide by dilational rheological measurements

In the present work, the interfacial dilational properties of hydrophobically modified polyacrylamide (HMPAM) at the kerosene/water interface were investigated by means of drop shape analysis method. The influence of petroleum acids on the dilational rheological behavior of HMPAM was expounded. The experimental results show that the dilational modulus of HMPAM layer can arrive at a high value of 80 mN/m for 2000 ppm polymer solution due to the formation of interfacial net structure by interactions among hydrophobic blocks of different HMPAM molecules. The petroleum acids molecules can interact with the hydrophobic blocks of HMPAM and form mixed micelle-like associations at interface, which will produce new fast relaxation process involving exchange of acid molecules between interfacial aggregates and free monomer at low HMPAM concentration, and destroy the interfacial net structure at high HMPAM concentration, respectively. Therefore, the moduli of HMPAM decrease obviously after adding petroleum acids, especially at higher HMPAM concentration.

Adsorption behavior and interfacial dilational properties of asphaltenes at the interface between n-decane/α-methylnaphthalene and brine water

As the complex component in crude oil, asphaltenes adsorb at the interface and exhibit unique interfacial properties, ruling the emulsifying properties and emulsion stability of produced fluid. Hence, this study deals with the adsorption behavior and interfacial dilational properties of asphaltenes. To investigate the adsorption behavior of asphaltenes, the dynamic interfacial tension is obtained with the pendant drop shape method at various concentrations and temperatures. Based on the adsorption kinetic equation, the adsorption behavior is found to be controlled by different mechanisms at different stages. The initial stage is dominated by the diffusion mechanism. Then, the adsorption process is gradually affected by diffusion and random sequential adsorption simultaneously. Finally, the controlling factor changes to the random sequential adsorption of adsorbed asphaltenes. A higher concentration of asphaltenes can accelerate the diffusion coefficient by increasing the concentration gradient, while the effect of temperature is weaker than concentration. Based on the experimental results, a new method is developed to quantify the influences of different mechanisms. After that, the droplet dilation experiment is carried out to probe the structural properties of the formed interfacial layer. By fitting the experimental data with the Langmuir equation of state, the average interfacial area occupied per asphaltene molecule is calculated. Finally, the emulsion stability experiments are carried out to support the conclusions in the interfacial experiments. This study enriches the adsorption kinetics theory of asphaltenes. It also contributes to the safe and economical transportation of produced fluid and rises the efficiency of demulsification.

Interfacial dilational properties of betaines and sulfonate mixtures: Effects of alkyl chain length

The dilational rheological properties of anionic/zwitterionic surfactant mixtures of sodium dialkyl sulfosucciantes (SNN10) and three betaines (SB12, SB14 and SB16) have been measured by means of a drop shape analysis method. It is established that SNN10 shows high interfacial activity due to tighter packing of the hydrophobic chains and the film properties of SNN10 is dominated by the in-interface process. When betaines and SNN10 are purposely mixed, the SNN10 molecule would be likely to displace the betaines molecule at the interface, and the displacement depends on the molecular structure of betaines: the shorter the hydrophobic chain, the easier it is to be replaced. In addition, adding SB16 to SNN10 would increase strength of the interfacial film at high surfactant concentrations.

Interfacial dilational properties of polyether demulsifiers: Effect of branching

The dilational rheology of two different types of polyether demulsifiers solutions, linear propylene glycol polyether and branched glycerol polyether, at the water-crude oil interface have been investigated by dilational rheological measurements. This paper research that except the concentration of 10 ppm, linear propylene glycol polyether appears higher moduli than those of branched polyether because branched one has shorter chain at the same molecular weight, which will result in the faster diffusion. However, at optimized concentration, the modulus of branched one is higher than that of linear one, which can be attributed to the stronger interactions between branched chains at interface. The linear demulsifier propylene glycol polyether shows stronger ability of reducing modulus for diluted crude oil with higher viscosity. On the contrary, branched demulsifier glycerol polyether acts well when concentrations of diluted crude oils are lower. The reason is that linear demulsifier has the stronger ability of adsorption and branched one shows the stronger ability of replacement of natural active fractions.

CO2-switchable dispersion of a natural chitosan and its application as a responsive pickering emulsifier

The natural chitosan aggregates obtained by increasing the pH of aqueous solutions are found to be responsive to CO2/N2 switching. These chitosan aggregates can be dispersed in water upon CO2 bubbling and precipitated out with N2 bubbling at room temperature. Liquid paraffin-in-water Pickering emulsions are prepared using these aggregates as the stabilizer. These emulsions can be demulsified completely with CO2 bubbling, and the separated two phases can be re-emulsified with N2 bubbling under mechanical mixing. This CO2/N2-switched demulsification/re-emulsification cycle can be repeated several times. The CO2/N2-switched dispersion/aggregation of the chitosan aggregates leads to desorption/adsorption of the aggregates at the oil/water interface and hence the disappearance/reconstruction of the three-dimensional network structure of the aggregates, which is responsible for the demulsification/re-emulsification. Experimental evidence including the measurement of interfacial tension, interfacial dilatational elastic modulus and rheological properties, and micrographs of formed emulsions is given to support the proposed stabilization mechanism.

Effect of EO group on the interfacial dilational rheology of fatty acid methyl ester solutions

The interfacial dilational rheological properties of oxyethylated fatty acid methyl ester solutions, C18=E3, C18=E5 and C18=E10, have been investigated by means of drop shape analysis method. The influences of oxyethylene (EO) numbers on interfacial dilational properties have been expounded. The experimental results show that the number of EO units plays a key role in controlling the interfacial film. C18=En is nonionic surfactant with long alkyl chain, meaning slower diffusion of the molecules to the interface. The EO units tend to lie flat at the interface as the number of EO unit increases and enter into the water sub-phase under compression, which causes the new relaxation process and results in an increase in the interfacial dilational modulus and the viscosity nature of film for C18=E5. The appearance of a more elastic film for the C18=E10 because the interfacial molecules can’t retain the compact structure due to the steric hindrance, which would weaken stronger intermolecular interaction and results in a decrease of dilational modulus.