Cotton, polyester and nylon can all be used in absorbent textiles, yet the fibers themselves interact with water in fundamentally different ways.
Cotton readily takes moisture into the fiber. Polyester takes very little water into its polymer structure. Nylon sits between the two. Yet a well-engineered polyester or polyester-nylon towel can still move large amounts of liquid from the skin.
The apparent contradiction disappears once three textile properties are separated: absorption, wicking and drying.
A fiber does not need to absorb large amounts of water into itself for a towel made from that fiber to move water effectively. Much of towel performance happens in the spaces between fibers, yarns and surface structures.
The Most Important Distinction: Fiber Absorption vs Fabric Absorbency
When people say that a towel “absorbs water,” they often combine several different physical processes into one word.
Water can:
- Enter the molecular structure of a hygroscopic fiber
- Wet the exterior surface of a fiber
- Move through microscopic channels between adjacent fibers
- Travel along a yarn by capillary action
- Collect in spaces between yarns or pile loops
- Remain temporarily trapped within the fabric structure
AATCC reflects this complexity by maintaining separate test methods for absorbency, liquid moisture management, vertical and horizontal wicking, drying time and drying rate. AATCC TM79 alone applies to yarns, fabrics and garments of any fiber content or construction.
Expert rule: “The fiber absorbs little moisture” does not automatically mean “the towel cannot absorb water.”
Three Fibers, Three Different Relationships With Water
Strongly hydrophilic
Cellulose contains numerous hydroxyl groups that interact readily with water through hydrogen bonding.
Strongly hydrophobic
PET has relatively few sites that strongly attract water, so little moisture enters the fiber itself.
Moderately moisture-responsive
Polyamide groups interact with water more readily than polyester, but nylon remains less hygroscopic than cotton.
What Is Moisture Regain?
Moisture regain is a textile measurement describing moisture held by a material at equilibrium, expressed relative to its dry mass.
ASTM D2654 provides methods for measuring moisture and moisture regain in natural and manufactured textile fibers. ASTM D1909 separately publishes commercial moisture-regain values used in textile trade calculations and cautions that these defined commercial values are not identical to actual experimental equilibrium values.
Typical literature values illustrate the enormous difference among fibers:
| Fiber | General moisture behavior | What that means physically |
|---|---|---|
| Cotton | High among the three; commonly reported around 7–8.5% under standard-type atmospheric conditions | Meaningful water uptake into the cellulose fiber itself |
| Nylon | Intermediate | Polyamide groups interact with water, so the fiber absorbs more atmospheric moisture than polyester |
| Polyester | Very low; commonly around 0.4% or lower depending on conditions | Very little water enters the PET fiber itself |
These numbers describe fiber hygroscopicity—not the total volume of liquid a completed towel can pick up from wet skin.
Why Cotton Loves Water
Cotton is primarily cellulose.
Cellulose contains many hydroxyl groups, which are polar chemical groups capable of hydrogen bonding with water molecules. This makes cotton intrinsically hydrophilic.
Water can move into accessible regions of the cotton fiber rather than remaining only on its exterior. Cotton also swells when wet, changing dimensions and mechanical behavior.
Textile literature commonly reports that cotton becomes stronger when wet—an unusual and useful property for a material repeatedly exposed to washing and drying.
Cotton Stores Water in More Than One Place
In a cotton terry towel, liquid may exist:
- Inside the cotton fibers
- Between individual fibers in a yarn
- Between neighboring yarns
- Within the spaces created by terry loops
- On the large external pile surface
This combination helps explain why cotton can hold substantial water.
It also helps explain why dense cotton towels may require considerable time and energy to dry: some water is not merely sitting on the surface waiting to evaporate.
Why Polyester Behaves Almost Oppositely
The polyester used in most towels is polyethylene terephthalate, or PET.
Its polymer structure has comparatively low affinity for water, and drawn polyester fibers contain tightly packed crystalline regions that further limit water entry.
Published textile literature commonly places polyester moisture regain at roughly 0.4% under ambient equilibrium conditions—dramatically lower than cotton.
This is why polyester itself is described as hydrophobic.
Then How Can a Polyester Microfiber Towel Absorb Water?
Because the water does not need to enter the polyester polymer to be transported by the fabric.
When filaments become extremely fine, a large number of narrow spaces are created between them. Once those surfaces are wettable, those spaces can act as capillaries.
Capillary pressure increases as the effective channel radius becomes smaller. In practical textile terms, many fine filaments can create a large total surface area and a network of narrow pathways through which liquid moves.
This is one of the central principles behind engineered microfiber textiles.
Cotton primarily combines fiber-level moisture absorption with capillary storage. Fine polyester relies much more heavily on surface wetting and capillary transport between fibers.
Why “Microfiber” Is a Geometric Term, Not a Fiber Chemistry
Microfiber refers to extremely fine manufactured fibers or filaments.
Polyester microfiber is still chemically polyester. Nylon microfiber is still nylon. Making the fibers finer does not transform polyester from a hydrophobic polymer into cellulose.
What fineness changes is geometry:
- More filaments can occupy a given yarn mass
- Total surface area rises
- Capillary spaces become finer and more numerous
- Liquid can spread through a larger network
That difference between chemical affinity and geometric capillarity is essential to understanding towel engineering.
Where Nylon Fits Between Cotton and Polyester
Nylon is a polyamide.
Unlike PET polyester, nylon contains amide groups capable of stronger interactions with water. It therefore absorbs more atmospheric moisture than polyester.
At the same time, nylon does not behave like cellulose cotton. Its overall moisture uptake remains lower, and its physical behavior is still that of a manufactured thermoplastic fiber.
This intermediate relationship with water is one reason nylon is frequently blended with polyester in fine-fiber textiles.
Why Polyester and Nylon Are Often Blended
Polyester-nylon blends are common in microfiber because the two polymers can contribute different properties.
Depending on the filament design and manufacturing process, the blend can be engineered for:
- Very fine filament structures
- Greater surface area
- Capillary water transport
- Soft hand
- Mechanical durability
- Controlled moisture interaction
The percentage blend alone does not tell you how absorbent a towel will be. Filament fineness, splitting, cross-sectional shape, yarn construction, pile geometry and finishing remain crucial.
What Is Split Microfiber?
Some microfiber yarns are produced as bicomponent filaments containing polyester and polyamide in the same initial filament structure.
Subsequent processing separates or “splits” the composite filament into much finer segments.
Splitting dramatically increases:
- Available fiber surface
- Number of fiber-to-fiber channels
- Potential capillary pathways
This is why two products both labeled “polyester/nylon microfiber” can perform very differently. The architecture of the filament matters as much as the blend ratio.
Absorption and Wicking Are Not the Same Thing
Absorption describes liquid being taken into a material or textile system.
Wicking describes liquid moving through the textile, generally by capillary forces.
A fiber can have low intrinsic moisture regain yet participate in a fabric with strong wicking behavior.
That is why AATCC maintains separate methods for absorbency and vertical or horizontal wicking.
Water Retention Is Different Again
ASTM D2402 measures water retained by textile fibers after thorough wetting and mechanical removal by centrifugation.
This illustrates another important distinction: how quickly water enters, how far it travels and how much remains afterward are separate properties.
For towels, high total water retention can be useful when drying a wet body—but greater retained water can also mean more moisture must subsequently evaporate.
Why Cotton Usually Takes Longer to Dry
Drying requires water to migrate to an evaporating surface and then move into the surrounding air.
Cotton tends to begin with more moisture because it can hold water both within the fiber and within the fabric structure.
Polyester absorbs very little water into the polymer itself, so once free water between filaments has evaporated, relatively little remains inside the fiber.
In controlled textile research comparing cotton and polyester, cotton initially held more water and took somewhat longer to finish drying because of that higher starting water content, even when the initial evaporation rates were similar.
Does That Mean Polyester Always Dries Faster?
No.
Fiber chemistry is only one part of drying.
A very thick polyester towel can still contain far more total water than a thin cotton towel. Important variables include:
- Fabric mass
- Pile height
- Pile density
- Fiber fineness
- Yarn density
- Airflow
- Ambient humidity
- How much water the towel picked up
This is why AATCC has multiple dedicated drying-rate test methods rather than inferring drying time from fiber name alone.
How Water Changes Cotton Mechanically
Cotton swells as it takes up water, and its mechanical properties change.
Unlike many fibers, cotton typically becomes stronger when wet. This is advantageous in towels because laundering and use repeatedly subject the textile to mechanical stress in a saturated state.
Swelling also changes the geometry of yarns and pores within the fabric, which can influence water movement and hand.
How Water Changes Nylon
Nylon also absorbs enough moisture for water to alter its material behavior.
Water can plasticize polyamide polymers, increasing molecular mobility and affecting dimensional and mechanical properties.
This is one reason moisture conditioning is important when testing nylon materials: their properties can vary with humidity to a greater extent than very low-regain polyester.
How Little Water Changes Polyester Internally
Polyester's very low moisture regain means atmospheric water has comparatively little effect on the bulk polymer.
This contributes to:
- Fast moisture release
- Dimensional stability in humid conditions
- Low fiber swelling
- Low intrinsic hygroscopicity
The downside is that untreated polyester surfaces are not naturally highly wettable, so absorbent polyester textiles depend heavily on filament geometry, finishing and capillary structure.
Why Surface Finishing Matters
A liquid cannot wick effectively through a capillary network if it refuses to wet the surfaces that form that network.
Textile finishing can therefore modify the surface energy of synthetic fibers and improve wetting.
This is why fiber chemistry alone does not predict the behavior of the final towel. A hydrophobic polymer can be incorporated into a highly water-moving textile when the surface and geometry are engineered correctly.
Why Fabric Softener Can Change Water Behavior
Textile softeners work partly by depositing lubricating compounds onto fiber surfaces.
Those deposits can alter surface energy and interfere with wetting. A towel may therefore feel softer while taking longer for water to penetrate its structure.
This effect is particularly important in towels because surface wetting is the first step in both fiber absorption and capillary transport.
Cotton and Polyester Interact Differently With Sweat and Skin Oils
Water is only one liquid a towel encounters.
Skin also transfers sebum and other lipids.
Controlled research comparing cotton and polyester found that cotton retained substantially more water while polyester showed greater affinity for sebum. That difference also influenced bacterial behavior on the textiles.
This matters because towel performance is not only a question of drying after one shower. Over repeated use and laundering, the textile must release both water-soluble and oily soils.
Why Nylon Is Useful in Fine-Fiber Blends
Nylon's role in a polyester-nylon towel is not simply “to make it absorbent.”
Depending on the construction, nylon can contribute to:
- Filament splitting behavior
- Surface wettability
- Soft tactile properties
- Mechanical flexibility
- Moisture interaction greater than polyester alone
But again, blend percentage is not enough to predict performance without knowing filament architecture and fabric structure.
Which Fiber Holds the Most Water?
At the fiber level, cotton clearly absorbs more moisture internally than polyester and generally more than nylon.
At the finished-towel level, however, the answer depends on construction.
A dense polyester-nylon microfiber towel with enormous capillary surface area may pick up more liquid from a surface than a poorly constructed cotton towel of similar dimensions.
This is why professional textile testing evaluates finished materials directly.
Which Fiber Wicks Water Best?
There is no universal winner.
Wicking is heavily controlled by:
- Fiber surface wettability
- Filament diameter
- Contact angle
- Yarn packing
- Pore radius
- Fabric construction
- Finishing
Fine synthetic filament systems can be excellent wickers precisely because narrow capillary channels can be engineered into the yarn.
Which Fiber Dries Fastest?
If all other variables were made comparable, polyester's low internal water uptake gives it a strong drying advantage.
But real towels are not equalized laboratory fiber samples.
A practical drying comparison needs to control fabric mass, construction, saturation level, airflow, temperature and humidity.
AATCC TM199, TM200 and TM201 exist because drying performance is itself a measurable textile property—not something that should simply be guessed from the fiber label.
Which Fiber Feels Wettest?
Wet sensation is influenced by more than how many grams of water are present.
Water location matters. Liquid concentrated at the textile-skin interface can feel wetter than the same mass distributed farther through a fabric.
Thermal conductivity, evaporation and surface contact all contribute to the perception.
That is one reason moisture-management textiles are often designed to move liquid away from the contact surface rather than merely maximize total water capacity.
How Textile Laboratories Separate These Properties
| Property | What it asks | Example standard |
|---|---|---|
| Absorbency | How readily does the textile take up water? | AATCC TM79 |
| Liquid moisture management | How does liquid spread and move through fabric? | AATCC TM195 |
| Vertical wicking | How quickly does water rise through the textile? | AATCC TM197 |
| Horizontal wicking | How does liquid spread laterally? | AATCC TM198 |
| Drying time | How long until moisture is removed? | AATCC TM199 |
| Drying rate | How rapidly is water lost under controlled conditions? | AATCC TM200 / TM201 |
| Fiber water retention | How much water remains after mechanical removal? | ASTM D2402 |
| Fiber moisture regain | How much atmospheric moisture enters the fiber at equilibrium? | ASTM D2654 |
Why You Cannot Judge a Towel From Fiber Content Alone
- Fiber chemistry controls intrinsic water affinity
- Fiber fineness controls surface area
- Yarn structure controls capillary spaces
- Pile geometry controls exposed surface
- Fabric mass controls how much material is present
- Finishing changes wettability
- Density changes pore size and water storage
- Laundering changes the surface over time
“100% cotton” is therefore not a complete performance specification.
Neither is “microfiber,” “polyester/nylon blend” or “high GSM.”
These labels tell you what the towel is made from. They do not fully tell you what the towel has been engineered to do.
Cotton vs Polyester vs Nylon: Expert Summary
| Property | Cotton | Polyester | Nylon |
|---|---|---|---|
| Polymer family | Cellulose | PET polyester | Polyamide |
| Intrinsic water affinity | High | Very low | Intermediate |
| Moisture regain | Relatively high | Very low | Moderate |
| Fiber swelling when wet | Meaningful | Minimal | Some moisture-dependent change |
| Internal fiber water | Significant | Very little | More than polyester, less than cotton |
| Capillary performance | Can be strong | Can be engineered to be extremely strong | Can contribute strongly in fine-filament systems |
| Drying tendency | Often slower | Often faster | Intermediate, construction dependent |
| Oil/sebum affinity | Lower than polyester | Relatively high | Construction dependent |
Frequently Asked Questions
Is cotton more absorbent than polyester?
At the fiber level, cotton absorbs far more water internally. At the finished-towel level, total water pickup also depends on fiber fineness, capillary structure, pile geometry, fabric mass and finishing.
How can polyester absorb water if it is hydrophobic?
Much of the water can be held and transported in microscopic spaces between fine filaments rather than inside the polyester polymer itself.
Is nylon hydrophilic?
Nylon absorbs more moisture than polyester because its amide groups interact with water, but it is still less hygroscopic than cotton.
Does microfiber absorb water?
A microfiber textile can pick up substantial liquid through high surface area and capillary action even when the base polymer itself has low moisture regain.
Why blend polyester and nylon in microfiber?
Bicomponent constructions can be split into extremely fine segments, creating large surface area and numerous capillary channels while combining different mechanical and surface properties.
Which dries faster: cotton or polyester?
Polyester generally has an advantage because very little water enters the fiber itself. Real towel drying still depends heavily on thickness, mass, pile, airflow and humidity.
Is wicking the same as absorbency?
No. Absorbency concerns water uptake; wicking concerns water movement through capillary pathways in the textile.
Can two towels with the same fiber content perform differently?
Very differently. Yarn size, filament fineness, pile geometry, density, finishing and GSM can all change moisture behavior even when the fiber percentages are identical.
Final Takeaway
Cotton, polyester and nylon solve the water problem in different ways.
Cotton is chemically attracted to water and absorbs meaningful moisture into the fiber itself. Polyester absorbs almost none internally, but fine polyester filaments can create powerful capillary networks that move water between fibers. Nylon occupies an intermediate chemical position and is frequently valuable in engineered fine-fiber systems.
None of these mechanisms alone determines whether a towel is “good.”
To understand towel performance properly, ask four separate questions: How does the fiber interact with water? How does the yarn move water? How does the fabric store water? And how quickly can the entire structure release it again?
That is the difference between reading a fiber label and understanding textile performance.
References
- AATCC. TM79-2025, Test Method for Absorbency of Textiles. Source
- AATCC. Standard Test Methods and Procedures. Source
- AATCC. Moisture Management Proficiency Testing Program. Source
- ASTM International. ASTM D2654-22, Standard Test Methods for Moisture in Textiles. Source
- ASTM International. ASTM D1909-13(2026), Standard Tables of Commercial Moisture Regains and Commercial Allowances for Textile Fibers. Source
- ASTM International. ASTM D2402, Standard Test Method for Water Retention of Textile Fibers. Source
- ASTM International. ASTM D2495, Standard Test Method for Moisture in Cotton by Oven-Drying. Source
- McQueen, R.H. et al. The Bacterial Life Cycle in Textiles Is Governed by Fiber Hydrophobicity. Microbiology Spectrum, 2021. Source
- Callewaert, C. et al. Microbial Odor Profile of Polyester and Cotton Clothes after a Fitness Session. Applied and Environmental Microbiology, 2014. Source
- ScienceDirect Topics. Textile Fiber—Moisture Regain and Fiber Properties. Source
- ScienceDirect Topics. Polyester Fiber. Source
- ScienceDirect Topics. Nylon Fiber and Moisture Interaction. Source
- Cotton Incorporated, CottonWorks™. Cotton Fiber Development and Structure. Source
- Cotton Incorporated, CottonWorks™. Cotton Home Buyer's Guide. Source
- Cotton Incorporated, CottonWorks™. Fiber and Yarn Fundamentals. Source
- AATCC. TM195, Test Method for Liquid Moisture Management Properties of Textile Fabrics. Source
- AATCC. TM197, Test Method for Vertical Wicking Rate of Textiles. Source
- AATCC. TM198, Test Method for Horizontal Wicking of Textiles. Source
- AATCC. TM199, Test Method for Drying Time of Textiles: Moisture Analyzer. Source
- AATCC. TM200, Test Method for Drying Rate of Textiles at Their Absorbent Capacity: Air Flow. Source
- AATCC. TM201, Test Method for Drying Rate of Fabrics: Heated Plate. Source
