NanoProof® 4.0

NanoProof® 4.0 is a hydrophobic/oleophilic siloxane based in hydrocarbon solvent, designed for up to IPX-6 level protection. Read more to see if NanoProof® 4.0 is the right technology for your more complex waterproofing challenges!

NanoProof® 4.0 Features

Water Contact Angle: 115°

Oil Contact Angle: 27°

Conductivity: Push Through Connectivity® capability

Thickness: 5-8 µm thickness

PCB Immersion in Salt Water: >60 minutes

Forgiving?: Yes, NanoProof® is more forgiving during application.

IPX6: i.e. High pressure water stream from any angle: Pass

Includes UV Tracer?: Yes.

Cure Required?: No, NanoProof® does not require a cure.

ROHS & REACH compliant?: Yes.

Application Method: Spray or Dip Applied

Dry Time:  20 minutes at room temperature

Deformable?: Yes, NanoProof® 4.0 has a gel-like finish; Handle with care.

Abrasion Resistance

While Aculon® NanoProof® PCB Water Protection Treatment can be handled after treatment during assembly, it is not meant for long term abrasion exposure and durability that would be experienced by a permanently exposed PCB.

Temperature Resistance

Aculon® NanoProof® PCB Water Protection Treatment is stable to 250C before the chemical structure is damaged and performance impacted. There is no known lower temperature threshold which damages the treatment.

Chemical Compatibility

Aqueous Solvents

NanoProof® 4.0 is confirmed compatible with Aqueous solvents of pH 6.5-8.5. More extreme acids and bases have not been tested to confirm impacts but it is not expected that aqueous solvents between PH of 2-10 should be problematic for the NanoProof® encapsulants.

Organic Solvents

NanoProof® 4.0 is not compatible with petroleum based solvents, as they will be dissolved and removed. As such, petroleum based solvents can be used to remove these specific NanoProof® for rework.

NanoProof® 4.0 is not compatible with fluorosolvents. As such, fluorosolvents can be used to remove these specific NanoProof® for rework.

How To Apply NanoProof® 4.0

Step 1: Clean

Parts must be sufficiently clean prior to treatment for proper bonding and effective application. See “Cleaning” tab for more detail.

Step 2: Treat

Spray – preferred method for 4.0

Apply Aculon® NanoProof® PCB Water Protection Encapsulants via spray gun. Aculon® NanoProof® PCB Water Protection Treatment comes in 1L Bottles for spray applications. Spray application typically results in treatment thickness of 50 nm – 20 µm depending on process parameters and chemistry selected.

Recommended Equipment:


Dip – optional method for 4.0

Fully immerse the part in the Aculon® NanoProof® PCB Water Protection Treatment solution for 30 seconds. Withdraw the part at a steady rate to ensure even coverage. Allow to dry or cure depending on your substrate. Aculon® NanoProof® PCB Water Protection Treatments come in convenient 1L quantities for dipping applications.


Utilization of Multiple Options

Please note that many customers have found significant success utilizing two or more of the available NanoProof® technologies successfully. Often times, the most sensitive components benefit from the most robust NanoProof® technology (5.1, 7.0, or 8.4) while the remaining components can be coated with the less robust treatments to benefit from their electrical push through capability, flexible nature and lower costs!



All NanoProof® products contain a UV Tracer which is visible under 365nm wavelength UV light (Detectable by both the human eye and automated detection systems). Please note that soldermasks and other substrate materials containing a UV tracer may make accurate detection of NanoProof® difficult.


Removal Solvents for Rework

Aculon recommends the below solvents for removal of NanoProof® from your board should rework be necessary.
NanoProof® 4.0 : Hydrocarbon solvents


Plastic Part Compatibility

Please refer to these general guidelines to determine if the NanoProof® product you are working with is compatible with your plastic parts that will come into NanoProof® in your manual or automated systems(tubing, pumps, gaskets, etc). Please note these are general guidelines for compatibility and it is recommended you test to confirm prior to implementation as Aculon® can not guarantee compatibility with your specific part.

NanoProof® 4.0

  • Compatible: PTFE, PET, Viton
  • Not Compatible: HDPE, LDPE, Polyurethane, PVC, Tygon, Noryl, ABS, PP, Polyphenol ethylene ether, silicone, neoprene, EPM, natural rubber


Masking Tape Compatibility

Please refer to these general guidelines to determine if the NanoProof® product you are working with to determine masking tapes that are compatible.

NanoProof® 4.0

Not Compatible: All known masking tapes and pastes. NanoProof® 1.0, 2.0, and 4.0 are specifically designed so that masking is almost never needed. If you require masking, a mask that is not damaged by hydrocarbon solvents will be required. Aculon is not aware of a compatible mask at this time.

A properly cleaned and prepared surface is imperative for Aculon® NanoProof® PCB Water Protection Treatment to properly bond with the surface and offer desired performance. The level of cleanliness can play a role in performance and durability/lifetime of the treatment. Cleaning Methods can be summarized into Good, Better, & Best Options. The below cleaning options assume that the part to be treated has been sufficiently degreased and cleaned of all visual contaminants first.


  • Blow the part clean with oil free compressed air
  • Rinse with IPA or other appropriate cleaning solvent


  • Use an appropriate Kyzen cleaner


  • clean room construction and a combination of the above


Have a high volume or complicated process and are not sure what level of cleaning your parts require? Contact Aculon® and we will work with you to determine the level of cleanliness needed for your application and to determine a cleaning method that fits your process.


Which application process is better? Dispensing, manual spray, or dipping?
ANSWER: Depends on the process you use and your part to be coated. No easy answer. Comes down to testing and what you need in the areas that are going to cause the most problems on your specific part. However in general spray is often preferred for application of 1.0, 3.5, 4.0, 5.0, & 5.1. Also keep in mind, 7.0 & 8.4 can not be applied via spray due to their thick nature and must be applied via dip or film coat.

What is the application rate?
ANSWER: Typical application time is 30 seconds for dipping.  However, every part is unique-so your part may need some process optimization.  The withdrawal speed will also impact the thickness.  Spraying can be done in seconds.

Do connections or solderable surfaces need to be masked?
ANSWER: This is dependent on the application and which NanoProof® is selected. No masking is typically required for application of NanoProof® 1.0, 3.5, 4.0, & 8.4. These materials are designed around having a push thru connectivity at all the times. Even days or weeks later – you can still push through.

Can you dip coat unsealed switches?
ANSWER: Yes, with NanoProof® 1, 3.5, 4.0, there is no problem with this.

What are the Carrier Solvents?
ANSWER: For NanoProof® 1.0, 3.5 & 4.0, the carrier is a Hydrocarbon Solvent.

Do we have measured viscosity of this treatment?
ANSWER: For NanoProof® 4.0 it is very low, less than a centipoise.

Does the applied thickness impact conductivity?
ANSWER: Our NanoProof® films themselves are not conductive. NanoProof® 1.0, 2.0, 3.5, 4 .0 & 8.4 will be able to push through (allowing electrical connections to be made) with no impact to conductivity.

Do the treated surfaces remain solderable or cna you solder through a treated PCBA?
ANSWER: For NanoProof® 1.0, 3.5 & 4.0, yes it is possible to solder through a treated PCBA. Once the film has set, take a clean room swab, dip in fluorosolvent, and rub over the area you want to solder.

Does this product have a low boiling point?
ANSWER: Boiling points for NanoProof® 1.0, 3.5 & 4.0 are in the 90 – 100°C range.

Can a regular test tape be used to test for adhesion?
ANSWER: An adhesion tape test is not really relevant for NanoProof® 1.0, 3.5, & 4.0 – these are actually still semi-liquid once they are down.

How do you suggest I test if a waterproof encapsulant is needed for my part? Also, how do you determine which NanoProof® meets my performance needs?

ANSWER: From working with our customers, we see that there is a huge variety of testing: we have manufacturers of medical devices that are worried about splashing of liquid on their device, other who need IPX7 qualification or others who require even longer periods of submersion in a variety of solutions.

Determine the level of exposure and performance you want the part to pass– connect the device (board), turn the power on the unit and test against those conditions.

If you want something very simple for humidity – go with something straightforward like NanoProof® 1.0. If you want full submersion of a running device over a long period of time NanoProof 7.0 OR 8.4 is likely most appropriate. NanoProof® 3.5, 4.0, 5.0, & 5.1 fit somewhere in the middle performance wise and are usually robust enough to meet most performance specs.

Do we have measured viscosity of this treatment?
ANSWER: For NanoProof® 4.0 it is very low, less than a centipoise.