Icephobic Coating Based on Novel SLIPS Made of Infused PTFE Fibers for Aerospace Application

Adrián Vicente; Pedro J Rivero; Nadine Rehfeld; Andreas Stake; Paloma García; Francisco Carreño; Julio Mora; Rafael Rodríguez

doi:10.3390/polym16050571

Icephobic Coating Based on Novel SLIPS Made of Infused PTFE Fibers for Aerospace Application

Polymers (Basel). 2024 Feb 20;16(5):571. doi: 10.3390/polym16050571.

Authors

Adrián Vicente^{1

2

3}, Pedro J Rivero^{1

2}, Nadine Rehfeld³, Andreas Stake³, Paloma García⁴, Francisco Carreño⁴, Julio Mora⁴, Rafael Rodríguez^{1

2}

Affiliations

¹ Engineering Department, Campus de Arrosadía S/N, Public University of Navarre, 31006 Pamplona, Spain.
² Institute for Advanced Materials and Mathematics (INAMAT2), Campus de Arrosadía S/N, Public University of Navarre, 31006 Pamplona, Spain.
³ Departmet Paint Technology, Fraunhofer Institute for Manufacturing Technology and Advanced Materials (IFAM), 28359 Bremen, Germany.
⁴ INTA-Instituto Nacional de Técnica Aeroespacial, Área de Materiales Metálicos, Ctra. Ajalvir km 4, 28850 Torrejón de Ardoz, Spain.

Abstract

The development of slippery surfaces has been widely investigated due to their excellent icephobic properties. A distinct kind of an ice-repellent structure known as a slippery liquid-infused porous surface (SLIPS) has recently drawn attention due to its simplicity and efficacy as a passive ice-protection method. These surfaces are well known for exhibiting very low ice adhesion values (τice < 20 kPa). In this study, pure Polytetrafluoroethylene (PTFE) fibers were fabricated using the electrospinning process to produce superhydrophobic (SHS) porous coatings on samples of the aeronautical alloy AA6061-T6. Due to the high fluorine-carbon bond strength, PTFE shows high resistance and chemical inertness to almost all corrosive reagents as well as extreme hydrophobicity and high thermal stability. However, these unique properties make PTFE difficult to process. For this reason, to develop PTFE fibers, the electrospinning technique has been used by an PTFE nanoparticles (nP PTFE) dispersion with addition of a very small amount of polyethylene oxide (PEO) followed with a sintering process (380 °C for 10 min) to melt the nP PTFE together and form uniform fibers. Once the porous matrix of PTFE fibers is attached, lubricating oil is added into the micro/nanoscale structure in the SHS in place of air to create a SLIPS. The experimental results show a high-water contact angle (WCA) ≈ 150° and low roll-off angle (αroll-off) ≈ 22° for SHS porous coating and a decrease in the WCA ≈ 100° and a very low αroll-off ≈ 15° for SLIPS coating. On one hand, ice adhesion centrifuge tests were conducted for two types of icing conditions (glaze and rime) accreted in an ice wind tunnel (IWT), as well as static ice at different ice adhesion centrifuge test facilities in order to compare the results for SHS, SLIPs and reference materials. This is considered a preliminary step in standardization efforts where similar performance are obtained. On the other hand, the ice adhesion results show 65 kPa in the case of SHS and 4.2 kPa of SLIPS for static ice and <10 kPa for rime and glace ice. These results imply a significant improvement in this type of coatings due to the combined effect of fibers PTFE and silicon oil lubricant.

Keywords: PTFE; SLIPS; electrospinning; low ice adhesion; super hydrophobic.

Grants and funding

Project RTI2018-096262-B-C41–MAITAI, funded by MCIN/AEI/10.13039/501100011033 and by ERDF “A way of making Europe”. Grant PRE2019-090656: funded by MCIN/AEI/10.13039/501100011033 and by ESF “Investing in your future”. Project PJUPNA1929 funded by MCIN/AEI/10.13039/501100011033 and by ERDF “A way of making Europe” and by BEI. Grant Erasmus+ funded by European Union.