Icephobic, Pt-Cured, Polydimethylsiloxane Nanocomposite Coatings
Yongfeng Liu, Chenyu Wang, Rebecca M. Jarrell, Sithara S. Nair, Kenneth J. Wynne, Duolong Di
Abstract
To explore novel coatings with potential for easy release of ice (icephobicity), a series of platinum-cured silicone coatings was prepared incorporating SYL-OFF 7210, designated MQ-R, as a nanoscale reinforcing component. These optically transparent coatings are designated according to cure temperature and MQ-R wt %, for example, Pt-PDMS(25)-20 for 25 °C cure and 20 wt % MQ-R. Surface characterization included dynamic contact angles and morphology by atomic force microscopy. Bulk characterization was accomplished with stress–strain measurements at 25 °C and dynamic mechanical analysis from −110 to 150 °C. Ice adhesion tests at −10 °C showed modulus had a dominant effect in increasing τice, the peak removal force. At −30 °C, storage modulus was greater for coatings cured at 100 °C compared to 25 °C, but ice removal tests at −30 °C (−22 °F) consistently showed τice for Pt-PDMS(100) MQ-R compositions was less than τice for corresponding Pt-PDMS(25) coatings. This unexpected result was explained by proposing that supercooled water at hydrophilic interfacial sites (−10 °C) does not impede ice removal but frozen water pins ice at −30 °C. Interestingly, MQ-R was found to be a reactive filler that increased modulus after 100 °C cure especially for Pt-PDMS(100)-30 (3 MPa) and Pt-PDMS(100)-40 (5 MPa). In summary, by virtue of resistance to ice adhesion Pt(PDMS) coatings with low MQ-R content have potential for conferring energy savings and safety while high MQ-R content results in noteworthy mechanical properties.