Article 2 | Why do glasses that are “more hydrophilic” sometimes get dirty more easily?

Jan 28,2026

I. A Confusing Real Phenomenon
At many construction sites, photovoltaic power plants, and curtain wall projects, you’ll often hear similar feedback:


“This glass coating was particularly hydrophilic right after it was applied.”
But after using it for a while, it actually appears dirtier than ordinary glass.
There are even more specific descriptions:
Surface Always damp and wet.
After the rain stopped, water marks were clearly visible.
Dust isn’t “a single layer of dust”; rather, it’s composed of patches that are darkened and mottled.
It doesn’t look like “dusty”—it looks more like “dirty.”
At this point, many people will instinctively think:
Is it perhaps not hydrophilic enough?
Is it possible that the coating has aged?
Should we make it “more hydrophilic”?
But the reality is just the opposite.

 

II. Let me state a key conclusion first.
        Not all “hydrophilic” treatments will make glass cleaner.
Some glasses that are “more hydrophilic” actually tend to show dirt more easily.


This statement may sound counterintuitive, but it’s incredibly important.

 

III. Let’s first clarify the matter of “hydrophilicity.”
In marketing, the term “hydrophilic” is used far too casually.


Many times, people take it for granted:
Hydrophilic = Water spreads evenly = Easily rinsed off = Clean
But in fact, Hydrophilicity can be divided into at least two completely different states.

 

IV. Two Types of “Hydrophilic Glass”—Most of the Problems You Encounter Stem From Here
Type 1: Instant hydrophilicity (in the days immediately following the procedure)
Characteristics:
Just completed construction.
It spreads out as soon as it touches water.
It looks like the effect is “very good.”


But this hydrophilicity often stems from:
Surface-residual active groups
An incompletely stable surface structure
Temporary chemical state


The problem is:
This hydrophilicity, It is inherently unstable.
It quickly deteriorates due to the effects of air, dust, and pollutants.

The second type: “hydrophilic wet surfaces” (the type that gets dirty most easily)
This is the most serious and also the most common type of problem.


Its performance is:
The surface has long been in a state of being “easily wetted.”
As soon as the air humidity rises, a water film forms.
After the water film evaporates, a noticeable water mark is left behind.
Sounds pretty hydrophilic, doesn't it?
But here's the problem.

 

5. Why does glass with a “long-term wet surface” actually get dirtier?
Let’s explain this step by step.

1️⃣ Water film ≠ cleansing action


Many people overlook a fact:
        Water itself doesn't clean.
Only “flowing water” can be clean.
If water is just:
Hanging on the surface
Laid out on the surface
It gradually evaporates again.
Then it does only one thing:
        👉 “Concentrate and retain” pollutants from the air

2️⃣ Water film evaporation is, in essence, “concentrating the dirt.”


The air isn't just filled with dust—it also contains:
Soluble salt
Organic pollutants
Industrial aerosol
Fine particulate matter (PM2.5)
When a water film is present:
These substances are dissolved or carried away by water.
As the moisture evaporates
        All remain on the glass surface.
So what you see isn’t “dust accumulation,” but rather:
Watermark
Mottled
Darkening
Local pollution is worsening.

 

Six, with this type of glass that becomes dirtier the more hydrophilic it is, the root of the problem isn't actually "hydrophilicity" itself.
but rather lies in two fatal flaws:

Defect 1: The issue of “electrostatic adsorption” remains unresolved.


Returning to the core issue we mentioned in Article 1:
Dust doesn't fall naturally.
Instead, it was attracted and held in place by static electricity.
Many traditional hydrophilic coatings:
Focus only on “water behavior”
Not paying attention to “electrical behavior”
The result is:
The surface continues to attract dust.
The water film merely “sticks the dust more firmly” to the surface.

Defect 2: Hydrophilicity is uncontrollable and irreversible.


Many hydrophilic coatings have a problem:
Initially highly hydrophilic
Later, it will either decay.
Either turn into “long-term intravenous infusion.”
And A truly good hydrophilic state , should be:
Dry state: Does not attract dust.
When there’s water: Water can spread and flow.
After drying: No marks left on the surface, and no stickiness returns.

 

7. So, what exactly is “correct hydrophilicity”?
We're taking a completely different route.


In our product design, there is one very clear principle:
        Hydrophilicity is not the goal.
The goal is “dust-free + easy to detach.”

 

8. How is our “ultra-hydrophilic” different from anything you’ve seen before?
Let’s break it down into three points and explain it in the simplest terms.

        ✅ First: Hydrophilicity is a “condition,” not the “norm.”


The surface isn't always wet.
It won't require long-term intravenous infusion.
Water marks won't form just because of air humidity.
Only when:
Rainwater
Condensation
Cleaning
Under humid conditions,

It will quickly enter a superhydrophilic state.

✅ Second: Antistatic treatment comes first; hydrophilicity is merely an “amplifier.”


This is the most critical difference.
In our system:
Anti-static → Dust is less likely to be attracted.
Superhydrophilic → Once water is present, dust is easier to be removed.
The order is reversed.
Not:
First, make it hydrophilic; then wait for the dust.
But:
First, don't vacuum; then use water to enhance cleaning.

✅ Third: The water flows cleanly, and the surface dries thoroughly as well.


Our design goal is not “drip infusion,” but rather:
Water can spread.
Water can flow away.
        After the water has flowed away, no trace remains on the surface.
This point is particularly important for photovoltaics, curtain walls, and daylighting glass.

 

9. Use the most straightforward analogy to help you fully understand.
Imagine two pieces of glass:


        Glass A:
Always damp
As soon as the dust comes, it gets stuck to the water.
Leaves a mark after it's done.
       Glass B:
Surface is dry
Dust doesn't easily stick.
As soon as there’s water, take it all away at once.
Which one is more “self-cleaning”?
The answer is very obvious.

 

10. To summarize this article in one sentence:


        True self-cleaning,
Not “always hydrophilic,”
Instead, it’s “dust-repellent + easy to clean.”

 

Preview | Why do many self-cleaning coatings only work effectively when there’s “heavy rain”?

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