Algae Adhesion onto Silicone is Sensitive to Environment-Induced Surface Restructuring

Abstract

Resistance to algae contamination is an important characteristic of insulators used in overhead power distribution in coastal environments. It is therefore important to understand the parameters governing algae adhesion onto polymer insulator materials such as silicone. Flow cell-based shear experiments were conducted in order to characterize the adhesion strength of algae onto polydimethylsiloxane surfaces, comparing fresh polymer substrates with those that have been soaked in water and saline solutions for 1 month. Both freshwater algae and seawater species could withstand considerably less drag force and were therefore more easily removed when the polymer was soaked in salt water. The polymer surface was found to be unaltered in terms of its roughness, contact angle, and lack of water uptake; no macroscopic surface characterization was therefore able to account for the differences in cell adhesion strength resulting from the soaking treatment. Surface-specific nonlinear vibrational spectroscopy, however, revealed subtle differences in the orientation of surface methyl groups that resulted from the water and saline exposure.

Elucidating the Changes in Molecular Structure at the Buried Interface of RTV Silicone Elastomers during Curing

“…The details of SFG theory and SFG results have been extensively presented in the literature, − and we will not repeat them here. Previously, our group has studied several silicone systems using SFG. ,,, In this study, SFG experiments were conducted using a picosecond SFG system (EKSPLA, Lithuania), which was described in detail in previous publications. ,,− Briefly, the system generated two input laser beams: a frequency tunable IR beam (2.3–10 μm) and a frequency fixed visible beam (532 nm).…”

Characterization of Buried Interfaces of Silicone Materials in Situ to Understand Their Fouling-Release, Antifouling, and Adhesion Properties

“…SFG is a second-order nonlinear optical spectroscopic technique capable of detecting the presence, coverage, and orientation of functional groups at surfaces and interfaces in situ . − SFG can be applied to study various material interfaces, including buried solid/liquid and solid/solid interfaces. Because of the selection rules of the second-order nonlinear optical process, under the electric dipole approximation, for most sample systems, only surfaces or interfaces (which do not have inversion symmetry) can generate the SFG signal, while bulk materials (with inversion symmetry) cannot.…”

“…Sum frequency generation (SFG) vibrational spectroscopy, on the other hand, is a technique that can nondestructively probe a buried interface in situ in real time. − This makes SFG an excellent technique for examining silicone surfaces and interfaces in different types of environments such as in air, in wet environments, or in contact with various solid materials. − We have extensively applied SFG to investigate interfacial molecular structures of silicone materials in different chemical environments used for many applications. ,,,− This feature article will summarize the SFG studies on PDMS materials and other components in silicone adhesives performed in our laboratory at the University of Michigan.…”

Hydration behaviors of nonfouling zwitterionic materials

“…3 In the marine industry, biofouling can increase the hydrodynamic drag of vessels and cause pitting and crevice corrosion of metal surfaces. 4,5 Marine biofouling-resistant coatings have traditionally relied on toxic biocide-containing paints, such as those containing tributyl tin-, copper-, and zinc-based biocides. 6,7 There is a high demand for novel environmentally benign or biocompatible coating materials that are effective against biofouling.…”