Surfactants Under Pressure: 5 Unexpected Factors That Reduce Their Efficiency and How to Prevent Them

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Surfactants play an indispensable role in a wide range of industrial applications – from cleaning agents and cosmetics to additives for coatings and adhesives. However, their effectiveness is not a given. Even minor errors in storage, handling, or combination with other substances can lead to degradation, loss of surface activity, or even undesirable reactions. In this article, we focus on five often-overlooked factors that can negatively impact surfactant performance and provide advice on how to prevent them. The right approach not only extends the lifespan of the raw material but also ensures consistent quality of your products.

1. Temperature extremes: When heat or frost disrupt micellar structure

Surfactants are sensitive to temperature fluctuations, which can significantly affect their effectiveness. At temperatures below freezing, there is a risk of crystallization or separation of active components, leading to permanent damage to micelle structure. Conversely, high temperatures (above 40 °C) accelerate molecular degradation, particularly in non-ionic surfactants, where ethoxylated chains break down. The result is a loss of wetting, foaming, or emulsifying ability. For optimal storage, a temperature between 10–25 °C is recommended, in sealed containers protected from direct sunlight.

In practice, even short-term exposure to extremes, such as during transport in summer or winter months, is often underestimated. If recommended temperatures are exceeded, it is advisable to perform control efficacy tests before use, such as measuring surface tension or foam stability. In sensitive applications, such as cosmetic preparations or industrial machine cleaning agents, even slight degradation can result in the failure of the entire product.

2. Contamination with water or impurities: How to avoid unwanted reactions

Surfactants are often supplied in concentrated form, increasing the risk of contamination due to improper handling. The ingress of water into a surfactant container can cause hydrolysis or microbial growth, particularly in anionic and amphoteric types. This leads to sludge formation, odour, or loss of functionality. Equally problematic are mechanical impurities, such as dust or metal particles, which can catalyse unwanted reactions or clog filters in application equipment.

Prevention involves adhering to Good Manufacturing Practice (GMP) principles: using clean and dry tools, closed dosing systems, and regular inspection of storage containers. For open systems, it is advisable to use an inert atmosphere (e.g., nitrogen) to minimize contact with moisture. If contamination occurs, the product must be filtered or replaced before use to prevent damage to the final product.

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3. Incorrect pH environment: Why even a small deviation can mean a big problem

The effectiveness of surfactants is highly dependent on the pH of the environment in which they are used. Anionic surfactants, such as alkyl sulfates or sulfonates, exhibit optimal performance in slightly acidic to neutral pH (5–8). At extremely low pH, they undergo protonation and lose solubility, while high pH can cause hydrolysis of ester bonds. Cationic surfactants, such as quaternary ammonium salts, are stable in alkaline environments but lose their activity in acidic pH.

Before using a surfactant, it is therefore essential to verify the pH of the final product and adjust it if necessary using buffers or acids/bases. For example, in industrial cleaning agents, surfactants are often combined with pH regulators to ensure long-term stability. In emulsions or dispersions, it is advisable to test the pH during storage, as changes may indicate the onset of degradation.

4. Interactions with other components: When surfactants "don’t get along" with additives

Surfactants are often part of complex formulations where they can interact with other components, such as preservatives, thickeners, or dyes. For example, anionic surfactants may form insoluble complexes with cationic substances (e.g., quaternary ammonium compounds), leading to cloudiness or precipitation. Similarly, nonionic surfactants can be deactivated by strong electrolytes, such as metal salts, which disrupt micellar structure.

To avoid undesirable interactions, it is crucial to perform compatibility tests before the final mixing of components. It is recommended to gradually add individual components while continuously stirring and monitoring changes in viscosity, color, or stability. In case of uncertainty, laboratory tests such as zeta potential measurement or microscopic analysis can also be used to identify potential issues before production.

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5. Long-term storage: How time and conditions reduce performance

Even when all the above factors are observed, long-term storage can lead to gradual degradation of surfactants. Oxidation by atmospheric oxygen, particularly in unsaturated chains, causes rancidity and loss of efficacy. In ethoxylated surfactants, gradual cleavage of ethoxylate units may occur, altering their hydrophilic-lipophilic balance (HLB). The result is reduced emulsifying capacity or changes in foaming properties.

To minimise these effects, it is advisable to observe the recommended shelf life (usually 12–24 months from the date of manufacture) and store surfactants in their original, undamaged packaging. For opened containers, it is necessary to ensure tight sealing and, if necessary, use stabilisers such as antioxidants. Regular checking of organoleptic properties (colour, odour) can detect early degradation and prevent production issues.

Mechanical Stress: How Mixing and Pumping Degrade Surfactants

Surfactants are sensitive to mechanical stress, which can disrupt their structure and reduce efficacy. During intensive mixing or pumping, foam formation and shear stress occur, breaking down micelles and reducing surface activity. This phenomenon is particularly problematic for anionic and non-ionic surfactants, where it can lead to permanent loss of detergent or emulsifying properties. In practice, this manifests, for example, in cleaning agents, where aggressive mixing reduces the ability to remove dirt, or in emulsions, which begin to separate.

Prevention involves optimizing mixing and pumping processes. It is recommended to use low stirrer speeds (ideally up to 300 rpm) and avoid high-pressure pumping, which generates shear forces. For sensitive formulations, it is advisable to add stabilizers such as polymeric thickeners or special additives that protect the micellar structure. It is also important to regularly monitor viscosity and surface tension, which can signal surfactant degradation. When handling concentrates, care should be taken to dilute them gently to avoid local overloading.

Effect of water hardness: Why minerals block surfactant efficacy

Water hardness, caused by high levels of calcium and magnesium ions, is one of the most common reasons for reduced surfactant efficacy. These ions react with anionic surfactants to form insoluble salts, which precipitate and lose their ability to reduce surface tension. The result is reduced foaming, poorer wetting, and lower detergent efficacy. For nonionic surfactants, the effect of hardness is less pronounced, but interactions that reduce emulsion or dispersion stability may still occur.

The solution is water treatment or the use of hardness-resistant surfactants. In industrial applications, water softeners based on phosphates or chelating agents such as EDTA are often used to bind metal ions and prevent their reaction with surfactants. An alternative is special surfactants with a modified structure, such as alkyl ether carboxylates or sulfonates, which are less sensitive to hardness. When formulating cleaning agents, it is advisable to test efficacy under conditions corresponding to real-world use, including simulating hard water according to standard methods.

Oxidation and Light: How to Protect Surfactants from Degradation

Surfactants containing unsaturated chains or sensitive functional groups can undergo oxidation, leading to their degradation. This process is accelerated by the presence of oxygen, high temperatures, or exposure to UV radiation. Oxidation manifests as yellowing, odor, or loss of functional properties, such as reduced foaming or emulsifying ability. In some surfactants, such as fatty alcohol ethoxylates, ethylene oxide cleavage may occur, altering their hydrophilic-lipophilic balance (HLB) and disrupting the stability of formulations.

Preventing oxidation involves several key measures. Storing in sealed containers made of dark glass or opaque plastic minimizes light exposure. Adding antioxidants, such as tocopherols or butylated hydroxytoluene (BHT), can significantly extend stability. It is also important to control storage temperature—ideally below 25 °C—and avoid direct sunlight. When handling surfactants, it is advisable to use an inert atmosphere (e.g., nitrogen) in containers to limit contact with oxygen. Regular testing of the peroxide value can help detect early stages of oxidation and prevent greater losses.

Need Advice on Selecting or Storing Surfactants?

Every surfactant requires an individual approach – from proper storage to compatibility with other ingredients. GCG Group provides detailed technical and safety data sheets for each raw material, and our experts are happy to advise you on selection and process optimization. Contact us – or browse our catalog of over 1,300 products right away.