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Schune C, Yonger M, Bresson B, Fretigny C, Guy L, Chaussée T, Lequeux F, Montes H, Verneuil E. Combining Ellipsometry and AFM To Probe Subnanometric Precursor Film Dynamics of Polystyrene Melts. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2019; 35:7727-7734. [PMID: 31117730 DOI: 10.1021/acs.langmuir.9b00768] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
We investigate the evolution over time of the space profiles of precursor films spreading away from a droplet of polymer in the poorly explored pseudo-partial wetting case. We use polystyrene melt droplets on oxidized silicon wafers. Interestingly, the film thicknesses measured by ellispometric microscopy are found in the 0.01 to 1 nm range. These thicknesses were validated by atomic force microscopy measurements performed on the textured film obtained after quenching at room temperature. From this, an effective thickness is obtained and compares well to the thicknesses measured by ellipsometry, validating the use of an optical method in this range of thickness. Ellipsometric microscopy provides a height resolution below the ångström with lateral resolution, image size, and framerate well adapted to spreading precursor films. From this, we demonstrate that precursor films of polystyrene consist of polymer chains with a surface density decreasing to zero away from the droplet. We further find that the polymer chains follow a simple diffusive law with the diffusion coefficient independent of density. This demonstrates that polystyrene chains spread independently in precursor films in pseudo-partial wetting condition. This behavior differs significantly from the case of chains spreading in total wetting for which the diffusion coefficient was found in the literature to depend on surface density or thickness.
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Affiliation(s)
- Claire Schune
- Soft Matter Sciences and Engineering (SIMM) , ESPCI Paris, PSL University, Sorbonne Université, CNRS , F-75005 Paris , France
| | - Marc Yonger
- Soft Matter Sciences and Engineering (SIMM) , ESPCI Paris, PSL University, Sorbonne Université, CNRS , F-75005 Paris , France
| | - Bruno Bresson
- Soft Matter Sciences and Engineering (SIMM) , ESPCI Paris, PSL University, Sorbonne Université, CNRS , F-75005 Paris , France
| | - Christian Fretigny
- Soft Matter Sciences and Engineering (SIMM) , ESPCI Paris, PSL University, Sorbonne Université, CNRS , F-75005 Paris , France
| | - Laurent Guy
- Solvay Silica , 15 rue Pierre Paÿs , BP 52, F-69660 Collonges-au-Mont-d'Or , France
| | - Thomas Chaussée
- Solvay Silica , 15 rue Pierre Paÿs , BP 52, F-69660 Collonges-au-Mont-d'Or , France
| | - François Lequeux
- Soft Matter Sciences and Engineering (SIMM) , ESPCI Paris, PSL University, Sorbonne Université, CNRS , F-75005 Paris , France
| | - Hélène Montes
- Soft Matter Sciences and Engineering (SIMM) , ESPCI Paris, PSL University, Sorbonne Université, CNRS , F-75005 Paris , France
| | - Emilie Verneuil
- Soft Matter Sciences and Engineering (SIMM) , ESPCI Paris, PSL University, Sorbonne Université, CNRS , F-75005 Paris , France
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The Utility of Nanocomposites in Fire Retardancy. MATERIALS 2010; 3:4580-4606. [PMID: 28883342 PMCID: PMC5445768 DOI: 10.3390/ma3094580] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/21/2010] [Revised: 07/27/2010] [Accepted: 08/31/2010] [Indexed: 11/17/2022]
Abstract
Nanocomposites have been shown to significantly reduce the peak heat release rate, as measured by cone calorimetry, for many polymers but they typically have no effect on the oxygen index or the UL-94 classification. In this review, we will cover what is known about the processes by which nanocomposite formation may bring this about. Montmorillonite will be the focus in this paper but attention will also be devoted to other materials, including carbon nanotubes and layered double hydroxides. A second section will be devoted to combinations of nanocomposite formation with conventional (and unconventional) fire retardants. The paper will conclude with a section attempting to forecast the future.
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Singh Meena J, Chu MC, Kuo SW, Chang FC, Ko FH. Improved reliability from a plasma-assisted metal-insulator-metal capacitor comprising a high-k HfO2 film on a flexible polyimide substrate. Phys Chem Chem Phys 2010; 12:2582-9. [DOI: 10.1039/b917604g] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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