Surface Science of a Filled Polydimethylsiloxane-Based Alkoxysilane-Cured Elastomer: RTV11

Area of Science:

• Materials Science
• Polymer Chemistry
• Surface Science

Background:

• Polydimethylsiloxane (PDMS)-based elastomers are utilized in various applications.
• Understanding the bulk and surface properties of PDMS elastomers is crucial for performance evaluation.
• RTV11 is a specific PDMS-based elastomer requiring detailed characterization.

Purpose of the Study:

• To characterize the RTV11 elastomer, including resin properties, cure kinetics, and surface characteristics.
• To investigate the stability of RTV11 films when aged in water.
• To evaluate the suitability of PDMS resins for nontoxic fouling release applications.

Main Methods:

• X-ray spectroscopy for chemical analysis (ESCA)
• Dynamic contact angle (DCA) analysis
• Attenuated total reflectance infrared spectroscopy (ATR-IR)
• Tapping mode atomic force microscopy (TM-AFM)
• Gravimetric analysis
• Energy dispersive X-ray analysis (EDX)
• Inductively coupled plasma atomic emission spectroscopy (ICP-AES)

Main Results:

• ESCA confirmed PDMS composition, with CaCO3 (32% bulk) undetected on the surface, indicating a PDMS network with a 1.3% siliceous domain.
• Water aging for three months led to increased surface roughness (micro-pits, 4% surface area) and mass loss (0.09%/wk).
• Surface erosion contributed minimally to mass loss, and CaCO3 showed surface depletion-limited loss during the initial immersion period.

Conclusions:

• The surface of RTV11 is predominantly a crosslinked PDMS network, with filler materials not significantly present.
• PDMS elastomer films exhibit surface degradation and mass loss upon prolonged water immersion.
• The findings support the use of alkoxysilane cured PDMS resins for nontoxic fouling release applications.