Rediscovering silicones: Molecularly smooth, low surface energy, unfilled, UV/Vis-transparent, extremely cross-linked, thermally stable, hard, elastic PDMS

Langmuir

Volumn 26, Issue 24, 2010, Pages 18585-18590

  Zheng, Peiwen ^a   McCarthy, Thomas J ^a  

^a UNIVERSITY OF MASSACHUSETTS   (United States)

Author keywords

[No Author keywords available]

Indexed keywords

CATALYST CONCENTRATION; CATALYTIC REACTIONS; CHEMICAL STRUCTURE; EXOTHERMS; LOW SURFACE ENERGY; PARTS PER MILLIONS; POLYDIMETHYLSILOXANE PDMS; STRUCTURE , PROPERTIES; THERMAL STABILITY; THERMALLY STABLE; TRANSPARENT GLASS;

BYPRODUCTS; CATALYSIS; CATALYSTS; CHEMICAL STABILITY; CROSSLINKING; INTERFACIAL ENERGY; MECHANICAL PROPERTIES; MICROCHANNELS; PLATINUM; SURFACE CHEMISTRY; SURFACE PROPERTIES; THERMODYNAMIC STABILITY;

SILICONES;

EID: 78650190192     PISSN: 07437463     EISSN: 15205827     Source Type: Journal    
DOI: 10.1021/la104065e     Document Type: Article

References (42)

1. Reference 2 is to the original report on PDMS synthesis. References 3 and 4 were chosen to emphasize that 60 years ago there was both a deep understanding of silicone chemistry and an appreciation of the wide range of applications of these materials. Reference 5 is a more modern, concise description of the broad field of silicones.
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26. -4 g/mL (based on Pt).
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31. 29Si signals at ̃δ-21 and ̃δ-34 were used to assess the conversion. See Supporting Information and ref 26.
32. Nanoindentation experiments were performed using a Hysitron TI 900 triboindenter with a Berkovitch-type diamond tip (radius of curvature of ̃150 nm). The load is applied to the surface while monitoring the penetration depth of the tip. From the loading and unloading curves, nanomechanical properties can be obtained. The same diamond tip was used to obtain AFM images of the surface at the specified indent positions after indentation.
33. A custom-built contact adhesion analysis instrument was used. A hemispherical glass probe (5 mm radius) was brought into contact with the sample surface at a fixed rate. The force, displacement, and contact area were recorded, and the stiffness and modulus could be calculated accordingly.
34. V sheet, and the samples were then heated to 150 °C to complete the curing. Sample dimensions were measured using calipers. An Instron 5800 R fitted with a 1 kN load cell was used and controlled by using the Merlin software package. Four samples were tested at a constant cross-head speed of 1 mm/min at room temperature. A preload was applied to eliminate compressive forces on specimens and improve the consistency of the measurements. An average Youngs modulus of 1.59 ± 0.16 (standard deviation) GPa was obtained from linear slopes of the stress-strain curves. This result is consistent with nanoindentation and contact adhesion data. Samples broke at a strain of 0.15-0.32%, and no yield behavior was observed.
35. Bhushan, B. Springer Handbook of Nanotechnology; Springer: New York, 2004; Vol. 1, p 677.
36. Possart, W. Adhesion: Current Research and Applications; Wiley-VCH: Berlin, 2005, p 36.
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38. Compression tests involved three cylindrical specimens with height-to-diameter ratios of 1:1. These were compressed using a 50 kN load cell at a 1%/min strain rate using the same Instron that was used for tensile tests. After release from up to 20% compression, all three samples recovered to their original dimensions; this was confirmed by caliper measurements. Minor crack propagation and barreling were observed during the compression; therefore, a modulus was not calculated. This test must be regarded as qualitative, but bulk elasticity was certainly demonstrated.
39. w1400-1800, Gelest), and ̃2 ppm Karstedts catalyst. The ratio of vinyl/hydridosilane groups was 1:5.
40. R) of these two silicone samples are within 1° is likely coincidental. We have recently reported (41) extensive contact angle data on supported poly(dimethylsiloxane) samples with negligible hysteresis.
41. Atomic force images were obtained using a Digital Instruments Dimension-3000 AFM in tapping mode.
42. Krumpfer, J. W.; McCarthy, T. J. Faraday Discuss. 2010, 146, 103