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HEMPASIL X3 Presentation
21
Hydrogel-Based Third Generation Fouling Release Coatings Green Coating – 12 November 2009 Effendy Salim Tow See Yei 16-Nov-09 1
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Transcript of HEMPASIL X3 Presentation
Hydrogel-Based Third Generation Fouling Release CoatingsGreen Coating – 12 November 2009Effendy SalimTow See Yei
16-Nov-09 1
Traditional fouling release coatings• ”Non-stick” properties
• ”Easy-clean” properties
16-Nov-09 2
Traditional fouling release coatings• ”Non-stick” properties
– Hydrophobic / Low surface tension– Smooth surface / Low skin friction
• ”Easy-clean” properties– Low elasticity modulus
16-Nov-09 3
Lowest adhesion strength at23-24 mJ/m2
PTFE
PDMS
Traditional fouling release coatings• ”Non-stick” properties
– Hydrophobic / Low surface tension– Smooth surface / Low skin friction
• ”Easy-clean” properties– Low elasticity modulus
16-Nov-09 4
Skin friction on Fouling Release coatings is 5% lower compared to Self-polishing Antifoulings
SP Antifouling
Fouling Release
Smooth plate
Traditional fouling release coatings• ”Non-stick” properties
– Hydrophobic / Low surface tension– Smooth / Low skin friction
• ”Easy-clean” properties– Low elasticity modulus
16-Nov-09 5
Lowest bioadhesion is found on PDMS binder
0
10
20
30
40
50
60
0 2 4 6 8 10 12 14
Bio
adhe
sion
(E·γc )½
16-Nov-09 6
2/1
⋅
⋅=t
EKP cγ
(Brady and Singer, 2000)
PDMS
PTFE
PS
PE
PMM
Performance and limitations of traditional Fouling Release coatings• Good performance in
vessels with medium high activity (>75%) and speed (>15 knots)
• Slime build-up after some time in service
16-Nov-09 7
Self-cleanability effect
Slime fouling
Working mechanism of Hydrogel-based Fouling Release coatings:
1. Fouling prevention– A Hydrogel layer at the coatings surface acts as
an invisible barrier that prevents fouling from adhering to the surface
2. Fouling release - Self cleanability– Very smooth surface– The pure silicone gives a highly flexible coating
16-Nov-09 8
What is a Hydrogel?
• A hydrogel is water entrapped in a network of hydrophilic polymers
• The polymers are superabsorbent with unique capacity for containing water
• Fouling organisms will perceive the hydrogel as a liquid
16-Nov-09 9
Fouling organisms perceive it as liquidto actual ship’s performance ?
Hydrogel silicone• Unique, non-reactive polymers form a hydrogel layer between the solid silicone
and seawater. • Fouling organisms perceive it as a liquid and are consequently unable to attach
to the hull.
Developed for speeds down to 8 knots
Silicone self-cleaning• Unlike conventional FR’s that are only partially silicone-based, X3 uses a
solid silicone topcoating.• Its pure silicone composition means HEMPASIL X3 significantly outperforms
conventional fouling release coatings in the self-cleaning stakes, especially at low speeds.
Hydrogel silicone
16-Nov-09 10
Contact angle measurements
Substrate Advancing CA Receding CA2nd Generation 105° ± 1°
Hydrogel-based 96° ± 1°
16-Nov-09 11
Substrate Advancing CA Receding CA2nd Generation 105° ± 1° 54° ± 1°
Hydrogel-based 96° ± 1° 23° ± 1°
Contact angle measurements
16-Nov-09 12
Bioassays – North Dakota State University
• Settlement and removal studies performed with– Cellulophaga lytica (marine bacterium)– Navicula incerta (marine microalgae)
• Reattached barnacle adhesion– B. Amphitrite (marine barnacle)
16-Nov-09 13
Cellulophaga lytica (marine bacterium)
16-Nov-09 14
Navicula incerta (marine microalgae)
16-Nov-09 15
B. Amphitrite (marine barnacle)
Attached/Broken
16-Nov-09 16
*1/0
9/0
9/0
0/9
* All 9 barnacles broke
Static immersion - 2 years Spain2nd Generation
Hydrogel-based
16-Nov-09 17
Dynamic immersion – 8 knots 60% activity2 years, Spain
2nd Generation
Hydrogel-based
16-Nov-09 18
Performance in vessels
Hydrogel Silicone SP Antifouling
Parameter DataVessel speed 13 knotsActivity 60%Service time 18 monthsIdle periods Up to 1 month
M/V Dimitris L. (source: Hempel)16-Nov-09 19
Performance in vessels
Hydrogel Silicone
Parameter DataVessel speed 8 knotsActivity 70%Service time 15 monthsIdle periods Up to 2 months
Sabino Segundo (source: Hempel)16-Nov-09 20
• Traditional Fouling Release coatings have shown weakness in prevention of slime fouling and even at target service conditions >15 knots and >75% activity
• Third Generation Fouling Release coatings based on Hydrogel silicone prevents fouling at speeds >8 knots and 50% activity
•Hydrogel-based silicone prolongs the slime-free period, thus increasing the fuel savings potential and reducing the CO2 emissions
Wrap-up
16-Nov-09 21
