The Mechanisms of Hydrophobic Recovery of Polydimethylsiloxane Elastomers Exposed to Partial Electrical Discharges

Kim, Jong-Soo; Chaudhury, Manoj K.; Owen, Michael J.; Orbeck, T.

doi:10.1006/jcis.2001.7909

Cited by 156 publications

(142 citation statements)

References 37 publications

Supporting

Mentioning

139

Contrasting

Order By: Relevance

“…The hydrophilic characteristic of PDMS tends to revert to their original hydrophobic states caused by the diffusion of lowmolecular-weight chains from the bulk PDMS to the oxidized surface. 35 As shown on the planar PDMS, the contact angle recovers to 99.7 ± 0.8° (Figure 4d) after aging for 40 h in ambient atmosphere. Notably, the tuning range of contact angle on planar PDMS is limited to ∼40.1°, which somewhat restricts the application of PDMS.…”

Section: Resultsmentioning

confidence: 52%

Morphology Defects Guided Pore Initiation during the Formation of Porous Anodic Alumina

Yang

Huang

Lin

et al. 2014

ACS Appl. Mater. Interfaces

View full text Add to dashboard Cite

Aluminum (Al) anodization leads to formation of porous structures with a broad spectrum of applications. Naturally or intentionally created defects on Al surfaces can greatly affect pore initiation. However, there is still a lack of systematic understanding on the defect dependent morphology evolution. In this paper, anodization processes on unpolished, polished, and nanoimprinted Al substrates are investigated under high voltages up to 600 V in various acid solutions. A porous structure is obtained on the unpolished and nanoimprinted Al foils with rough surface texture, whereas a compact film can be rationally obtained on the polished Al foil with a highly smooth surface. The observation of surface roughness dependent oxide film morphology evolution could be originated from the high voltages, which increases the threshold requirement of defect size or density for the pore initiation. Electrostatics simulation results indicate that inhomogeneous electric field and its corresponding localized high current induced by the surface roughness facilitate the initiation of nanopores. In addition, the porous films are utilized as templates to produce polydimethylsiloxane nanocone and submicrowire arrays. The nanoarrays with different aspect ratios present tunable wettability with the contact angles ranging from 144.6°to 56.7°, which hold promising potentials in microfluidic devices and self-cleaning coatings.

show abstract

Section: Resultsmentioning

confidence: 52%

Morphology Defects Guided Pore Initiation during the Formation of Porous Anodic Alumina

Yang

Huang

Lin

et al. 2014

ACS Appl. Mater. Interfaces

View full text Add to dashboard Cite

show abstract

“…The fluorine content decreased by 6% when samples were simply stored in ambient conditions for 30 days pointing towards a re-orientation/migration of the fluorine groups away from the surface during aging. The introduction of functional groups onto the surface of silicone has been recognized to lack stability due to the reorganization of silicone elastomers over time [26,27,29,31,32]. The phenomena of hydrophobic recovery upon PDMS plasma oxidation has been extensively investigated, and explained namely by the reorientation of surface hydrophilic groups towards the bulk and/or reorientation of non-polar groups in the bulk towards the surface, by the diffusion of pre-existing low molecular weight (LMW) species through the bulk to the surface, or migration of created LMW species during treatment to the surface [26].…”

Section: Chemical Composition and Stabilitymentioning

confidence: 99%

Fluorination of poly(dimethylsiloxane) surfaces by low pressure CF4 plasma – physicochemical and antifouling properties

Cordeiro¹,

Nitschke²,

Janke³

et al. 2009

Express Polym. Lett.

View full text Add to dashboard Cite

Abstract. Fluorinated surface groups were introduced into poly(dimethylsiloxane) (PDMS) coatings by plasma treatment using a low pressure radio frequency discharge operated with tetrafluoromethane. Substrates were placed in a remote position downstream the discharge. Discharge power and treatment time were tuned to alter the chemical composition of the plasma treated PDMS surface. The physicochemical properties and stability of the fluorine containing PDMS were characterized by X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM) and contact angle measurements. Smooth PDMS coatings with a fluorine content up to 47% were attainable. The CF4 plasma treatment generated a harder, non-brittle layer at the top-most surface of the PDMS. No changes of surface morphology were observed upon one week incubation in aqueous media. Surprisingly, the PDMS surface was more hydrophilic after the introduction of fluorine. This may be explained by an increased exposure of oxygen containing moieties towards the surface upon re-orientation of fluorinated groups towards the bulk, and/or be a consequence of oxidation effects associated with the plasma treatment. Experiments with strains of marine bacteria with different surface energies, Cobetia marina and Marinobacter hydrocarbonoclasticus, showed a significant decrease of bacteria attachment upon fluorination of the PDMS surface. Altogether, the CF4 plasma treatments successfully introduced fluorinated groups into the PDMS, being a robust and versatile surface modification technology that may find application where a minimization of bacterial adhesion is required.

show abstract

“…16 The main reasons for hydrophobic recovery are the reorientation of the polar groups from the surface to the bulk, 16 diffusion of pre-existing low-molecular-weight species from the bulk to the surface, 15 and condensation of the hydroxyl groups. 17 The recovery rate is also affected by storage condition such as temperature, 10 humidity, 18 aqueous fluid, 19 and surfactants 20 used to store the PDMS device. To our knowledge, limited or very few studies report on surface modification using a bonded and sealed PDMS device.…”

Section: Introductionmentioning

confidence: 99%

Oxygen plasma treatment for reducing hydrophobicity of a sealed polydimethylsiloxane microchannel

et al. 2010

View full text Add to dashboard Cite

Rapid prototyping of polydimethylsiloxane ͑PDMS͒ is often used to build microfluidic devices. However, the inherent hydrophobic nature of the material limits the use of PDMS in many applications. While different methods have been developed to transform the hydrophobic PDMS surface to a hydrophilic surface, the actual implementation proved to be time consuming due to differences in equipment and the need for characterization. This paper reports a simple and easy protocol combining a second extended oxygen plasma treatments and proper storage to produce usable hydrophilic PDMS devices. The results show that at a plasma power of 70 W, an extended treatment of over 5 min would allow the PDMS surface to remain hydrophilic for more than 6 h. Storing the treated PDMS devices in deionized water would allow them to maintain their hydrophilicity for weeks. Atomic force microscopy analysis shows that a longer oxygen plasma time produces a smoother surface.

show abstract

The Mechanisms of Hydrophobic Recovery of Polydimethylsiloxane Elastomers Exposed to Partial Electrical Discharges

Cited by 156 publications

References 37 publications

Morphology Defects Guided Pore Initiation during the Formation of Porous Anodic Alumina

Morphology Defects Guided Pore Initiation during the Formation of Porous Anodic Alumina

Fluorination of poly(dimethylsiloxane) surfaces by low pressure CF4 plasma – physicochemical and antifouling properties

Oxygen plasma treatment for reducing hydrophobicity of a sealed polydimethylsiloxane microchannel

Contact Info

Product

Resources

About