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عنوان فارسی مقاله:
کنترل مورفولوژی در لایه های نازک PS: مخلوط هموپلیمر PLA با رسوب پوشش شیب
عنوان انگلیسی مقاله:
Morphology control in thin films of PS:PLA homopolymer blends by dip-coating deposition
سال انتشار : 2017
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مقدمه انگلیسی مقاله:
1. Introduction
When a blend of immiscible homopolymers is deposited from a solution of the polymers in a common solvent, the morphology of the film after drying results from the superposition of complex phenomena such as phase separation process, dewetting and vitrification of the system. Depending on the evaporation rate, the phase separation and the dewetting can be stopped into more or less advanced stages [1–8]. This provides a wide variety of thin film morphologies including co-continuous or dis-continuous laterally phase-separated morphologies as well as layered systems. The compositional heterogeneities length scale can vary from few tens of nanometers to several microns [9].When deposited by spincoating, it is rather difficult to vary significantly the deposition parameters for a given polymer/solvent pair, and post-treatments are often necessary to direct the morphology in the film (like thermal or solvent – SVA – annealing) [10]. On the other hand, it is now well established that experimental conditions in dip-coating such as the withdrawal speed, the nature of the solvent, or the concentration of the solvent vapors above the reservoir can be tuned in order to significantly influence the properties of the final dried films [11–13]. Studying dip-coating from sol-gel solutions, Faustini et al. [11] demonstrated that within withdrawal speed from 0.01 to 20 mm s−1 deposition occurs in two specific regimes, namely the capillary and the draining regimes (for low and high withdrawal speed respectively). The physical processes of the film formation are different [14], leading to a “V” shaped thickness evolution. Extensively studied in the case of sol-gel process, the dip-coating of polymer solutions has been reported for a limited number of examples including photovoltaic applications [13,15] or block copolymer thin films [12,16–19]. Very recently, it has been demonstrated in a series of papers by Roland et al.[12,20,21]that the “V” shaped thickness evolution for supramolecular block copolymer films formed by dip-coating was verified. It was also shown in these works that the morphology was highly influenced by the withdrawal speed, allowing for morphology control in a very simple way, without the need of additional post-annealing techniques.In this work, we have exploited the versatility of the deposition process by dip-coating in order to direct the morphology in thin films of polymer blends. We focused our investigation on blends of polystyrene (PS) and polylactic acid (PLA) that can be used, in case of a laterally phase separated morphology, as masks for etching as demonstrated in previous work from our group [22]. We varied the type of solvent used to prepare the polymer solution, the withdrawal speed and also the configuration of the reservoir containing the solution to be deposited in order to generate various evaporation conditions. Dip-coating of polymer blends using such a large variety of deposition speed and solvent quality has, to the best of our knowledge, not been yet reported. In the first part of the paper, we focus on the thickness variations of the film as a function of the deposition parameters. In the second part, we examine the morphology of two PS and PLA blends.
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کلمات کلیدی:
Solvent Influence on Thickness, Composition, and Morphology ... pubs.acs.org/doi/abs/10.1021/acs.macromol.5b00847 by S Roland - 2015 - Cited by 12 - Related articles Jul 17, 2015 - The variation in film morphology with solvent and dip-coating rate ... Morphology control in thin films of PS:PLA homopolymer blends by ... Morphology control strategies for solution-processed organic ... pubs.rsc.org/en/content/articlehtml/2014/ee/c4ee00688g by Y Diao - 2014 - Cited by 108 - Related articles May 30, 2014 - ... of strategies to control thin film morphology towards enhancing their electronic ... thin-film morphology, specifically, the control of nucleation, crystal growth, ...... 10 Highly aligned meta-stable C8-BTBT:PS film fabricated by ... Rapid and reversible morphology control in thin films of poly(ethylene ... https://www.nature.com/pj/journal/v44/n6/pdf/pj201267a.pdf?origin=ppub by R Goseki - 2012 - Cited by 14 - Related articles Apr 18, 2012 - Rapid and reversible morphology control in thin films .... PS and PMMA, the PEO at an isotropic state possesses highly mobile chains, which ... Composition and Morphology Control in Mesoporous Non-ionic Templated ... https://books.google.com/books?isbn=0549485589 Erik Karl Richman - 2008 deposition solution, ps is the density of the solvent that evaporates, and pf is the density of the final film. Here we used the density of ethanol (0.789g/cm3) for ps ... [PDF]Morphology Control and Ordering of PS- b-PMMA Block ... - UWSpace https://uwspace.uwaterloo.ca/bitstream/handle/.../Baradaran_Shokouhi_Babak.pdf?...1 by BS Babak - 2015 - Related articles Morphology Control and Ordering of PS- ... to control BCP morphologies. ..... 5.1.2 Coating PS-b-PMMA BCP Thin Film With a Surface Neutralizing Underlayer . Morphology control of LiCoO 2 thin film prepared by ... - IEEE Xplore ieeexplore.ieee.org/abstract/document/6893727/ by D Liu - 2014 - Related articles Abstract: LiCoO2 thin film samples have been prepared by pulsed laser deposition under different deposition conditions. A series of tests have been done to ...
