A Panoramic Guide to Surfactants: Definitions & Mechanisms, Key Metrics, Application Scenarios, and Selection Navigation (Tables 1–3)

1) What is a surfactant?

A surfactant (surfactant / surface-active agent) refers to a class of substances that reduce the surface tension of the solution/continuous phase in which they are dissolved, and/or reduce the interfacial tension with another phase. Therefore, they preferentially adsorb at gas–liquid or liquid–liquid / liquid–solid interfaces. Substances that are only slightly soluble but can spontaneously spread at the surface and likewise reduce surface tension may also be called surfactants.

A simple way to understand it: a surfactant is like a molecule that automatically “runs to the boundary to stand guard.” One end “likes” water, while the other end “likes” oil/air—so it is especially good at making things that are originally incompatible more willing to come into contact.

2) What do surfactants do?

The most fundamental role of surfactants is:

Reduce surface/interfacial tension → easier spreading, wetting, emulsification, dispersion, foaming, or defoaming.

Break the mechanism into three steps:

• First, “occupy” the interface: molecules preferentially adsorb at interfaces such as water–air, water–oil, and water–solid (the interface is “rearranged”).
• Lower the “cost” of forming an interface: surface/interfacial tension decreases, so water spreads more readily, and oil droplets are easier to break up and remain stably dispersed.
• At sufficient concentration, they “self-assemble”: when the surfactant concentration reaches a certain level, aggregates such as micelles (micelles/aggregates) form. Their hydrophobic core can encapsulate oily soil/hydrophobic molecules and carry them away. This threshold is the CMC (critical micelle concentration). CMC is not a constant—it is strongly affected by temperature, salinity/electrolytes, cosolvents, etc.

Note: More foam ≠ stronger cleaning. Cleaning performance depends more on wetting, emulsification/solubilization, and detachment of soil from surfaces; foam is mainly an observable “appearance.”

3) How are surface-active substances classified?

A. Classification by “hydrophilic headgroup charge”

Category	Typical characteristics	Common use examples
Anionic	Strong detergency and foaming; skin irritation is relatively more common	Main surfactant in laundry detergents/dishwashing liquids; shampoos
Cationic	Easily adsorbs to negatively charged surfaces/fibers; often used for antimicrobial or conditioning/softening	Hair conditioners; disinfection/antibacterial formulations; fabric softeners
Amphoteric / zwitterionic	Mild, hard-water tolerant, good compatibility with other surfactants	Mild personal care; baby/sensitive-skin systems
Nonionic	Strong emulsification/solubilization; relatively less sensitive to electrolytes (depending on structure)	Emulsions; food/pharmaceutical excipients; industrial cleaning

Notes:

• Amphoteric: charge state changes with pH (can be cationic or anionic).
• Zwitterionic: carries both positive and negative charges on the same molecule; overall electrically neutral (often remains zwitterionic over a wide pH range).

B. Classification by source or “greenness”

• b1 Petrochemical synthetic surfactants: stable performance and controllable cost, but biodegradability and ecotoxicity should be considered.
• b2 Natural/biological surfactants (biosurfactants): e.g., glycolipids, lipopeptides, etc., often highlighted for renewability and environmental friendliness; however, cost, batch-to-batch consistency, and regulatory pathways may be more complex (product-dependent).

4) What are the “key metrics” for surfactants?

Metric	What it answers	Why it matters	Common methods / standards
Surface tension / interfacial tension (γ)	“How low can it reduce the tension?”	Impacts wetting, spreading, emulsification, and cleaning efficiency	du Noüy ring and Wilhelmy plate methods are commonly used; ASTM D1331 covers related measurement methods
CMC (critical micelle concentration)	“At what concentration do micelles start to form?”	Determines the turning point for solubilization/detergency; above the CMC, adding more surfactant typically no longer significantly lowers surface tension (cost-effectiveness)	Inflection point of the surface-tension–concentration curve, etc.; CMC is a core physicochemical parameter
HLB (hydrophilic–lipophilic balance)	“More hydrophilic or more lipophilic?”	Quick screening for whether it is better suited to O/W vs W/O emulsification and solubilization	HLB 0–20 is a commonly used scale; classic rule of thumb: low HLB → W/O, high HLB → O/W (the Griffin system is widely cited)
Krafft point (common for ionic surfactants)	“Will it fail to dissolve or stop working at low temperature?”	Below this temperature, solubility is insufficient and micelles are difficult to form → performance drops	Definitions and the solubility/CMC relationship are commonly used to evaluate ionic surfactants
Cloud point (common for EO-type nonionics)	“Will it become cloudy and phase-separate upon heating?”	Affects high-temperature cleaning, formulation stability, and phase behavior	ISO 1065 mainly targets cloud-point determination for ethoxylated (EO-derived) nonionic surfactants
Biodegradability / ecotoxicity	“What happens after discharge into the environment?”	Determines regulatory compliance and environmental risk; many cleaning systems prioritize these assessments	OECD 301 is a commonly used screening framework for ready biodegradability; eco-label schemes for cleaning products often differentiate surfactants by biodegradability and aquatic toxicity

Additional note on HLB: HLB is most useful as an empirical starting point for nonionic emulsifiers/monomeric surfactants. For mixed surfactants, polymeric emulsifiers, or strongly ionic systems, HLB is only a rough starting point—phase behavior, droplet size, and stability must be verified experimentally.

5) What capabilities do surfactants provide, and where are they used?

A practical table of “engineering capabilities” created by converting ‘tension reduction’ into function:

Engineering capability	What “interfacial problem” it solves	Typical application scenarios	Common surfactant types / selection tips
Wetting	Lowers liquid–gas / liquid–solid interfacial tension so liquids spread and penetrate pores/rough surfaces	Coating, cleaning, pesticide spraying, substrate pre-wetting	Low surface tension / fast-adsorbing types; silicone surfactants wet strongly but require attention to formulation compatibility
Emulsification	Lowers oil–water interfacial tension and forms an interfacial film to prevent droplet coalescence; stability also depends on interfacial film strength/rheology and electrostatic/steric repulsion	Cosmetic emulsions, food emulsification, drug/fragrance emulsification	Nonionics are common (HLB approach: high HLB → O/W, low HLB → W/O); often blended with co-emulsifiers
Dispersion	Helps solid particles “wet + deagglomerate,” and prevents re-agglomeration via electrostatic/steric stabilization; also depends on ζ-potential/steric layer, ionic strength, and shear history	Pigments, ceramic slurries, nanomaterials, carbon black/filler dispersion	Anionic/nonionic/polymeric dispersants are common; key is particle size, ionic strength, and shear conditions
Solubilization	Above CMC, micelles encapsulate hydrophobes in the hydrophobic core, greatly increasing apparent solubility	Fragrance solubilization, solubilizing hydrophobic actives, lab membrane solubilization/lysis	Pay attention to CMC and micelle structure
Detergency	Wetting + emulsification/solubilization + lifting soil off surfaces and keeping it suspended to prevent redeposition	Laundry, dishwashing, industrial degreasing	Anionics: strong cleaning + foaming; amphoteric/nonionic: reduce irritation and improve hard-water tolerance
Foaming / foam stabilization	Forms an elastic film at the gas–liquid interface to delay foam collapse (sometimes foam suppression is needed instead)	Personal-care foaming, firefighting foam, foamed materials; fermentation/coating often requires foam control	Strong foaming ≠ strong detergency; industrial processes often need low foam or a defoamer
Antistatic / conditioning	Cationics adsorb onto negatively charged surfaces (fibers/hair/skin), reducing friction and static and improving feel	Fabric softening, hair-conditioning, antistatic finishing	Typically quaternary-ammonium cationic surfactants; watch compatibility with anionic systems (can “fight” and lose efficacy)

6) Advantages and risk points of surfactants

Table A | Advantages of surfactants

Advantage	Detailed description	Notes
High efficiency	Small dosages can markedly change interfacial properties; many properties show clear turning points/slope changes as concentration approaches CMC.	Solubilization usually requires ≥ CMC; detergency is not fully equivalent to micellization
Multi-functionality	The same class of molecules can work across different interfacial processes: wetting, emulsification, dispersion, solubilization, foaming/defoaming, etc.	Emphasizes a “toolbox for interfacial processes”
Strong tunability	By tuning headgroup, chain length, EO number, branching/aromatic rings, ion pairing, etc., one can emphasize strong cleaning, mildness, low foam, salt tolerance, and other priorities	Performance trade-offs exist

Table B | Risk points and mitigation

Risk point	Typical mechanism/manifestation	Notes	Common mitigation
Skin irritation / barrier disruption	May cause dryness, stinging, and barrier damage risks via protein denaturation and disruption/extraction of stratum-corneum lipids; anionics (e.g., SLS) are often considered “harsher.” Cationic quaternary ammonium surfactants may also be more irritating/stronger membrane-active (especially for skin/mucosa), though they are more often used for conditioning/antimicrobial effects than as high-dose primary cleaners.	“Related to surfactant type, but more strongly influenced by concentration, pH, contact time, and the overall formulation system.”	Blend with amphoteric/nonionic; reduce active level; add oils/humectants/lipid replenishment; shorten contact time for rinse-off products
Large variation in environmental burden	Biodegradability and aquatic toxicity vary greatly with structure; eco-labels/regulations often control based on biodegradability and aquatic-toxicity metrics.	“OECD 301 is a ready-biodegradability screen; assessment must also consider products and use scenarios.” “Biodegradable” depends on structure and environmental conditions.	Prioritize OECD 301 screening; combine aquatic-toxicity assessment and frameworks such as total formulation CDV, etc.
Formulation compatibility / stability issues	Hard-water Ca²⁺/Mg²⁺ can precipitate some anionic surfactants; salt/electrolytes and temperature shift CMC, phase behavior, and cloud point/turbidity, causing phase separation, abnormal viscosity, foam runaway, etc.	“Environmental changes = changes in interfaces and aggregation states—this is a common root cause of failure.”	Choose hard-water-tolerant systems or add chelators; control salinity/temperature windows; adjust nonionic EO number/HLB; use blends to improve phase behavior

7) Surfactant Selection Guide and Representative Product Tables

Selection Navigation

Dimension (ask yourself first)	Typical scenarios / keywords	Which table to check first	Selection logic	Representative products
Cell lysis / protein extraction (preserve activity when possible, or routine lysis)	“Lysis buffer, RIPA, co-IP, WB/ELISA wash, permeabilization, membrane-protein solubilization”	Table 1 | Detergents for bio/protein/membrane research	Table 1 focuses on lab-favorite detergent systems (nonionic / amphoteric / bile salts / glycosides), spanning a practical “mild → strong” gradient that maps well to biochemical workflows.	Triton™ X-100 / NP-40 type; CHAPS/CHAPSO; sodium cholate/sodium deoxycholate; DDM/maltosides; SDS (strongly denaturing)
Membrane-protein structural work / reconstitution (cryo-EM, X-ray, NMR)	“Membrane-protein stability, micelles, detergent exchange & reconstitution, low background/high purity, structural biology”	Table 1 | Detergents for bio/protein/membrane research	Membrane proteins are sensitive to detergent mildness, purity, and stabilizing behavior; in Table 1, glycosides/maltosides/zwitterionic detergents are often used as a primary screening set.	DDM (n-dodecyl-β-D-maltoside); 1-O-decyl-β-D-maltoside; DPC; CHAPS/CHAPSO; OGP
Denaturing electrophoresis sample prep	“SDS-PAGE, full denaturation, sharper bands”	Table 1	Denaturing electrophoresis typically requires a strong anionic detergent to impart charge and unfold proteins; Table 1 includes the canonical option.	Sodium dodecyl sulfate (SDS)
Endotoxin removal / temperature-controlled phase separation enrichment	“Triton X-114 phase separation, cloud point, endotoxin, phase-partition enrichment”	Table 1	These applications rely on specific detergent physicochemical properties (cloud point/phase separation) and are closer to biochemical process operations.	Triton™ X-114
Emulsification / solubilization / formulation development (cosmetics, cleaning, pharma solubilization)	“HLB, O/W or W/O, clear solubilization, essential oils/fragrances, microemulsions, emulsion stability”	Table 2 | Formulation emulsifiers/solubilizers & mild cleansing systems	Table 2 centers on “formulation engineering” surfactants—Tween/Span/PEG-40 HCO/Poloxamer, etc.—suited to emulsion and solubilization system design.	Tween® 20/80; Span® 20/60/80; PEG-40 hydrogenated castor oil; Kolliphor® P 407; AOT (microemulsions/reverse micelles)
Mild cleansing / foaming systems (low-irritation blending)	“Mild, low irritation, foaming/foam stability, facial cleanser/shampoo, irritation reduction by blending”	Table 2	Table 2 includes common mild routes: amino-acid surfactants, betaines, APG, SLES/SLSA, etc.—ideal for a “primary surfactant + co-surfactant” framework.	Cocamidopropyl betaine; sodium lauroyl glutamate; dodecyl glucoside; SLES; SLSA; sodium lauroyl isethionate
Materials synthesis / surface modification / templated nanomaterials	“Mesoporous templates, nanoparticle surface modification, phase transfer, cationic modification”	Table 3 | Cationic surfactants/antimicrobial preservatives/analytical standards (priority) + check Table 2 if needed	These uses often rely on cationic quaternary ammonium salts (templating/adsorption/phase transfer). If emulsification/solubilization is needed, return to Table 2 for formulation surfactants.	CTAB; DTAB; HTAC; (for phase transfer/emulsification, blend with Tween/Span as needed)
Antimicrobial / preservative / disinfection-related (formulations or methods)	“Quats, antimicrobial, disinfection, preservative challenge test”	Table 3	Table 3 compiles typical cationic antimicrobial systems and pharmacopeial/solution-form products—good for direct screening along the antimicrobial route.	Benzalkonium chloride; cetylpyridinium chloride (Ph. Eur.); DDAC
Analytical methods / QC / standards (not for formulation dosing)	“Standard solution, calibration, environmental analysis, titration”	Table 3	Table 3 includes standards and titrants—more suitable for QC/method development than as bulk formulation ingredients.	PFOA analytical standard; SDBS standard solution; benzethonium chloride titrant
Only know “milder vs stronger,” not sure what to pick	“Mild, activity-preserving, strong detergency, blending”	Start with Table 1 (biochem) or Table 2 (formulation), then return to Table 3 when charge/antimicrobial/templating is needed	First choose the table by application field, then within the table screen progressively: nonionic/amphoteric → strong anionic detergency → cationic special uses for maximum efficiency.	Biochem: DDM/CHAPS → Triton → SDS; Formulation: APG/CAPB/amino-acid → SLES/AOS; Special: CTAB/BAC/DDAC

Table 1 | Common Detergents for Bio/Protein/Membrane Research

(Lysis, membrane-protein solubilization, bile salts / zwitterionics / glycoside systems)

Category	CAS No.	Aladdin Cat. No.	Name	Spec / Purity	Key features & applications
Nonionic | PEG alkyl ether	9002-92-0	T434384	Polyethylene glycol monododecyl ether	For membrane research	Mild nonionic detergent/solubilizer; used for membrane studies, membrane-protein solubilization and reconstitution; relatively less denaturing.
Anionic | Sulfate (strong detergency/denaturing)	151-21-3	S432158	Sodium dodecyl sulfate (SDS)	For electrophoresis, anionic	Classic strong anionic detergent; for SDS-PAGE denaturing sample prep and thorough protein solubilization; strongly disrupts protein structure, not suitable for activity-preserving extraction.
Nonionic | Alkyl aryl poly(oxyethylene) ether (Triton-type)	9002-93-1	T109028	Triton X-100 (Triton™ X-100)	For electrophoresis	Classic nonionic lysis agent; cell lysis, mild membrane-protein solubilization, tissue/membrane permeabilization; often used to reduce background in immunoassays (detergent choice may need screening for certain membrane proteins).
Nonionic | Alkyl aryl poly(oxyethylene) ether (Triton-type)	9036-19-5	T101474	Triton™ X-114	Reagent grade	Nonionic detergent with cloud-point phase separation; used for temperature-controlled phase partition enrichment of membrane proteins and removal of LPS/endotoxin; suitable for workflows requiring thermal phase separation.
Nonionic | Alkylphenol ethoxylate (NP-40 type)	9016-45-9	N1372295	Nonylphenol ethoxylate (Tergitol NP-40)	Isomer mixture, white flakes	NP-40-type nonionic lysis detergent; for cell lysis, protein solubilization, and immunoassay washing; alkylphenol ethoxylates require extra attention to environmental/compliance considerations (more common in research settings).
Anionic | Amino-acid surfactant (sarcosinate)	137-16-6	N432003	Sodium N-lauroyl sarcosinate	Detergent for cell lysis	Relatively mild anionic surfactant; for cell lysis/protein extraction, cleaning, and irritation reduction in formulations; often chosen as a “milder than SDS” option.
Anionic | Bile salt	302-95-4	S485305	Sodium deoxycholate	For manufacturing of diagnostic kits and reagents	Bile-salt detergent; common in RIPA lysis systems to solubilize membrane proteins/lipoproteins; milder for some proteins but sensitive to salt/temperature/pH (formulation optimization needed).
Anionic | Bile salt	361-09-1	S161419	Sodium cholate	Moligand™, ≥98%	Bile-salt detergent; used for solubilizing membrane-protein/lipid systems and building mixed micelles; common in liposome/membrane-mimetic systems; ≥98% supports better reproducibility.
Anionic | Taurocholate	145-42-6	S100834	Sodium taurocholate	≥95%	More hydrophilic bile salt; used for membrane-protein solubilization and lipid/cholesterol micelle construction; often used as a “more physiologically relevant bile-salt” model.
Zwitterionic | CHAPS (bile-acid-based sulfobetaine)	75621-03-3	C274335	3-[(3-cholamidopropyl)dimethylammonio]-1-propanesulfonate (CHAPS)	Ultra-pure grade	Classic zwitterionic detergent; mild and more activity-friendly; widely used for membrane-protein solubilization, IEF, and protein complex studies; “ultra-pure” suits high-sensitivity experiments.
Zwitterionic | CHAPSO (more hydrophilic CHAPS-type)	82473-24-3	C434255	CHAPSO	UltraBio™, ultra-pure	Mild zwitterionic detergent (CHAPSO-type); more hydrophilic; used to solubilize/stabilize membrane proteins/complexes and reduce aggregation; suitable when purity/low background is critical.
Zwitterionic | Phosphocholine (DPC)	29557-51-5	N130416	n-Dodecylphosphocholine (DPC)	≥99%	Zwitterionic detergent; commonly used for membrane-protein micelles, NMR/structural screening, and functional maintenance; ≥99% is suitable for impurity/background-sensitive studies.
Nonionic | Glycoside (alkyl glucoside, short-chain OG)	29836-26-8	O105510	n-Octyl-β-D-glucopyranoside (OGP)	For protein analysis, ≥98%	Mild glycoside detergent; used for membrane-protein solubilization/refolding and structural work; relatively easy to dialyze/remove (higher CMC, helpful for downstream reconstitution).
Nonionic | Glycoside (APG, decyl glucoside)	58846-77-8	D112862	Decyl glucopyranoside	Biochemical reagent	Mild, low-irritation sugar-based surfactant; used for gentle membrane-protein solubilization and stabilization of enzyme/protein systems; also common in personal-care/cleaning as a mild primary/co-surfactant.
Nonionic | Maltoside (DDM)	69227-93-6	N475300	n-Dodecyl-β-D-maltoside (DDM)	UltraBio™, ultra-pure, ≥98%	One of the “gold-standard” mild detergents for membrane proteins; often preserves structure/activity well; widely used in structural biology (cryo-EM/X-ray) and functional studies; ultra-pure grade improves reproducibility and lowers background.
Nonionic | Maltoside (decyl maltoside)	82494-09-5	D124517	1-O-Decyl-β-D-maltoside	≥97%	Mild nonionic detergent (shorter chain → easier removal/higher CMC); used for membrane-protein solubilization and reconstitution; suitable when rapid detergent exchange/removal is needed downstream.
Amphoteric / zwitterionic | Amine oxide	1643-20-5	N755731	Dodecyldimethylamine oxide	BioReagent, ≥99%(NT), ≥99.0% (NT)	Amine-oxide surfactant (relatively mild, good compatibility); used for membrane-protein solubilization, cleaning, and formulation foaming/foam stabilization; can be blended with anionics to improve detergency while moderating irritation.
Natural surfactant | Saponin (Digitonin)	11024-24-1	D104508	Digitonin	50%	Classic mild saponin detergent; cholesterol-affine; used for selective plasma-membrane permeabilization, solubilization of cholesterol-rich membrane domains, and preserving protein-complex architecture as much as possible.

Table 2 | Formulation Emulsification/Solubilization & Mild Cleansing Systems

(HLB tuning, solubilization, foaming, and mild routes)

Category	CAS No.	Aladdin Cat. No.	Name	Spec / Purity	Key features & applications
Nonionic | Polysorbate (Tween)	9005-65-6	T485985	Tween® 80	Viscous liquid, preservative-free, low peroxide; low carbonyl	High-HLB solubilizer/emulsifier; commonly used for solubilization and stabilization in protein/vaccine/biologics formulations; “low peroxide/low carbonyl” is preferred for oxidation-sensitive systems.
Nonionic | Polysorbate (Tween)	9005-64-5	T104863	Tween® 20 (TWEEN® 20)	Viscous liquid	High-HLB solubilization/wetting; often added to ELISA/Western wash buffers to reduce nonspecific adsorption; also used for gentle solubilization of membrane-associated components.
Nonionic | Sorbitan fatty-acid ester (Span)	1338-43-8	S431923	Span 80	Viscosity 1000–2000 mPa·s (20 °C)	Low-HLB W/O emulsifier; suited for oil-phase systems and inverse emulsions/microemulsions; often blended with Tween 80 to tune HLB for O/W ↔ W/O switching and stability.
Nonionic | Sorbitan fatty-acid ester (Span)	1338-39-2	S1372587	Span® 20	For synthesis	Low-HLB W/O emulsifier/co-emulsifier; often blended with Tween 20 to tune HLB; used for synthesis, oil-phase dispersion, and emulsion stabilization.
Nonionic | Sorbitan fatty-acid ester (Span)	1338-41-6	S112961	Span 60	Nonionic surfactant	Low-HLB W/O emulsifier; more oriented toward thickening/structuring and emulsion stability; common in creams/ointments and oil-rich systems; can be blended with Tween to tune HLB.
Nonionic | Block copolymer (Poloxamer/Pluronic)	9003-11-6	K434429	Kolliphor® P 407	Ethylene oxide 71.5–74.9%	Poloxamer 407 (PEO–PPO–PEO) solubilizer/stabilizer; used for hydrophobic drug solubilization, protein stabilization, and cell-culture additives; also common in thermoresponsive gel/sustained-release research.
Anionic | Sulfosuccinate (Docusate/AOT)	577-11-7	D476741	Sodium dioctyl sulfosuccinate (AOT)	PharmPure™, USP	Has both pharmacopeial grade and surfactant functionality; used in microemulsions/reverse micelles (reverse-micellar solvation), dispersion, and interfacial studies; USP grade is better for pharma-related R&D/QC.
Amphoteric | Betaine (CAPB)	61789-40-0	C665446	Cocamidopropyl betaine	Active content 28%–32% in water	Classic mild amphoteric surfactant; often used as a co-surfactant to boost foam/stability, reduce irritation, and improve skin feel; compatible with anionic surfactants—good for cleansing/personal-care formulation development.
Anionic | Amino-acid surfactant (glutamate)	29923-31-7	S339866	Sodium lauroyl glutamate	≥95%	Amino-acid-based mild anionic surfactant; used for mild cleansing, foaming, and sensory optimization; suitable for “low irritation + blendable” formulation routes and comparative screening.
Anionic | Sulfoacetate (SLSA)	1847-58-1	S305259	Sodium lauryl sulfoacetate	≥97%	Relatively mild anionic foaming surfactant; used in personal-care/cleaning formulations with fine foam; also usable for basic interfacial/micelle research.
Anionic | Isethionate (Sodium lauryl isethionate)	7381-01-3	S736361	Sodium lauroyl isethionate	≥95%	Mild anionic surfactant (common in syndet facial cleansers/soap-free systems); fine foam and relatively lower irritation; suitable for mild-cleansing formulation and system benchmarking.
Anionic | Alpha-olefin sulfonate (AOS)	68439-57-6	S304377	Sodium alpha-olefin sulfonate	≥92%	High detergency and hard-water tolerance; widely used in laundry/cleaning and industrial cleaning; suitable for systems demanding strong foam and cleaning performance.
Nonionic | Glycoside (APG, dodecyl glucoside)	110615-47-9	L196324	Dodecyl glucoside	≥40%	APG-type mild nonionic surfactant (solution/assay form); used for mild cleansing, solubilization, and irritation reduction in formulations; also usable for gentle solubilization screening in membrane-related systems.
Anionic | Ether sulfate (SLES)	9004-82-4	S196294	Sodium laureth sulfate	≥25%	Classic anionic primary foaming surfactant (SLES); used in shampoos/body washes/cleaning systems; balances foam and cleaning; blending with amphoterics can reduce irritation and stabilize foam.
Nonionic | PEG-40 hydrogenated castor oil (PEG-40 HCO)	61788-85-0	E196259	PEG-40 hydrogenated castor oil	—	Strong solubilizing nonionic surfactant; used for solubilizing fragrances/essential oils/lipophilic actives and for clear formulations and microemulsions; good when “clear appearance + high solubilization capacity” is needed.

Table 3 | Cationic Surfactants / Antimicrobial Preservatives / Analytical Standards

(Quaternary ammonium systems + standards/titrants)

Category	CAS No.	Aladdin Cat. No.	Name	Spec / Purity	Key features & applications
Cationic | Quaternary ammonium (pyridinium salt)	6004-24-6	H433048	Cetylpyridinium chloride monohydrate	European Pharmacopoeia (Ph. Eur.)	Antimicrobial quaternary ammonium (CPC); used in oral-care/antimicrobial research and formulations; also used as a cationic surfactant for interfacial control and adsorption studies.
Cationic | Quaternary ammonium (CTAB type)	57-09-0	H108986	Cetyltrimethylammonium bromide (CTAB)	Ion-pair chromatography grade, ≥99%	Strong cationic surfactant; widely used as a template in materials synthesis (e.g., mesoporous silica), nanoparticle synthesis and surface modification; also used as an ion-pair/chromatography additive and in phase-transfer systems.
Cationic | Quaternary ammonium (DTAB type)	1119-94-4	D431486	Dodecyltrimethylammonium bromide (DTAB)	BioReagent Plus, ≥99%	Cationic detergent; used for micelle/interfacial charge control, materials–biomacromolecule interaction studies; can also solubilize certain membrane systems (shorter chain than CTAB).
Cationic | Double-chain quaternary ammonium (DDAC)	7173-51-5	N194743	Didecyldimethylammonium chloride (DDAC)	≥95%	Strong cationic surfactant/biocide; used in disinfection, antimicrobial surface treatments, and phase-transfer emulsification; double long chains enhance adsorption and antimicrobial performance.
Cationic | Quaternary ammonium (CTAC solution)	112-02-7	C466513	Cetyltrimethylammonium chloride solution (HTAC)	25 wt.% in H₂O	Cationic surfactant solution (CTAC/HTAC); used for phase transfer, emulsification, and surface modification (cationization of particles/fibers/films); aqueous solution is convenient for direct dosing.
Cationic | Quaternary ammonium (disinfection/preservation, BAC)	8001-54-5	A304666	Benzalkonium chloride	80% ethanol solution	Broad-spectrum antimicrobial quaternary ammonium; used in disinfection, preservation, and surface-treatment research; ethanol solution form is convenient for preparation and antimicrobial/method development experiments.
Cationic | Quaternary ammonium (analytical titrant)	121-54-0	H128347	Benzethonium chloride analytical titrant	Analytical titrant, 0.04 M	Commonly used for surfactant-related QC and two-phase titration (e.g., determining anionic surfactant content); suitable for method development and QC experiments.
Fluorinated surfactant | PFAS (analytical standard)	335-67-1	P106681	Perfluorooctanoic acid (PFOA)	Analytical standard, for environmental analysis	Typical PFAS (fluorinated surfactant/pollutant) analytical standard; used for PFAS method development, QC, and quantification in environmental samples.
Anionic | Aryl sulfonate (SDBS standard)	25155-30-0	S117593	Sodium dodecylbenzenesulfonate standard solution (SDBS)	Analytical standard, 1000 µg/mL in water	Standard solution of an anionic aryl-sulfonate surfactant; used for environmental/method quantification, instrument calibration, and QC; also a reference in surfactant behavior/micelle studies.

Note: The above are representative Aladdin products. For more specifications, please refer to the product list at the end of this article, or search the Aladdin website by product name/CAS number.

Aladdin: https://www.aladdinsci.com/