PETG (Polyethylene Terephthalate Glycol-modified) is a transparent, durable thermoplastic widely used in packaging, medical devices, and display applications. The addition of glycol during polymerisation improves its processability compared to standard PET, reducing brittleness while maintaining strength and clarity.
Like many thermoplastics, PETG has inherently low surface energy. This low surface energy prevents good wetting which results in poor adhesion characteristics. Plasma treatment effectively overcomes the limitation by cleaning and activating the PETG surface, significantly increasing wettability and enabling strong, durable bonds without altering the bulk material properties.
PETG
| Before Plasma treatment |
After Plasma treatment |
| Contact Angle 70.98 ± 5.14O | Contact Angle 7.05 ± 1.07O |
 |
 |
| Surface energy 48.53 ± 4.90mN/m | Surface energy 80.03 ± 0.42mN/m |
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FAQs
Q: How long does PETG stay activated after plasma treatment?
A: Surface activation is strongest immediately following plasma treatment. Over time, surface energy decays due to the motion of molecules at the polymer surface (termed hydrophobic recovery). Surface activation of PETG can last for many days, with only gradual reduction as hydrophobic recovery takes longer due to its amorphous nature.
Q: Can PETG be plasma treated to improve adhesion?
A: Yes. Plasma treatment increses PETG's surface energy, making it suitable for coatings, inks, adhesives, and laminates.
Q: Does plasma treatment change the appearance of PETG?
A: No. plasma treatment only modifies the outermost surface chemistry, preserving PETG’s optical clarity and gloss.
