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Journal ArticleDOI

A multi-step cold plasma process for fine tuning of polymer nanostructuring

TL;DR: In this paper, the authors studied the effect of the input power on the morphology of polyaniline nanostructures on the chemical and morphological properties of the polymer.
About: This article is published in Progress in Organic Coatings.The article was published on 2019-03-01 and is currently open access. It has received 6 citations till now. The article focuses on the topics: Polyaniline.

Summary (1 min read)

1. Introduction

  • One-dimensional polymers’ structures have attracted a growing interest recently due to their interesting properties such as a high shape factor.
  • While chemical and electrochemical syntheses of one-dimensional structures were widely studied [4-13], they require some additional chemicals such as oxidants and acids as well as postsynthesis steps of filtration and drying.
  • Some groups have reported the formation of nanostructured plasma polymerized (pp) films.
  • It consists in varying the input power during deposition, starting with a high value in order to form polymer nuclei followed by a low value to preserve the monomer structure.
  • Moreover, in order to illustrate the importance of surface structuring for some applications, their textured pp-ANI films are tested for their sensitivity to ammonia gas.

2. Experimental

  • 1. Substrate preparation Polyaniline films were deposited onto clean silicon wafers (100).
  • The sample was placed on the water cooled substrate-holder situated in the post-discharge zone, at the bottom center of the chamber.
  • The spectra were taken with the electron emission angle at 90° relative to the sample surface, yielding a maximum sampling depth around 10 nm due to the mean free path of the electrons.
  • After inserting the pp-ANI sensor inside the measuring chamber, a certain amount of dried ammonia gas, diluted in nitrogen gas, was introduced into the measuring chamber.

3. Results and Discussion

  • The first part of this section is dedicated to the two-step process where a high power is applied for a short time before low-power deposition that creates a nanostructured surface with preservation of the monomer entity.
  • These radicals could produce different reactions, chain reorganization or scission in the upper layer (60 W) altering its chemical structure.
  • These data reflect the morphology of pp-ANI films determined by AFM.
  • Moreover, at a given power, the sensitivity decreases with the rise of deposition time to become, in some cases, lower than that of the smooth layer.
  • 2.2. Influence of the second step duration.

4. Conclusion

  • A surface clustering preserving the monomer structure takes place during plasma deposition of polyaniline with power variation.
  • However this stage should be short to limit the destruction of the formed clusters.
  • This method is supposed to be suitable for any type of monomer since the formation of nanostructures does not depend on chemical structure of the polymer.
  • These textured films have shown an improved sensitivity to ammonia compared to the smooth layer if elaborated at short first step power and duration in the two-step process.
  • Moreover, the middle layer formed with the three-step process allows controlling the chemistry of all the pp-ANI film.

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Journal ArticleDOI
10 Aug 2021
TL;DR: The cold atmospheric plasma (CAP) is a promising and rapidly emerging technology for a wide range of applications, from daily life to industry as mentioned in this paper, and its key advantage is its unique ability to eff...
Abstract: Cold atmospheric plasma (CAP) is a promising and rapidly emerging technology for a wide range of applications, from daily life to industry. CAP’s key advantage is its unique ability to eff...

13 citations

Journal ArticleDOI
TL;DR: In this article, the photoreduction and photostabilization ability of 2, 2′-disulfanediylbis (9H-thioxanthen-9-one) was used for in-situ preparation of Au nanoparticles either in solution or in poly(ethylene glycol) methyl ether acrylate / poly(polyethylenes glycol diacrylate polymer matrix.

11 citations

Journal ArticleDOI
TL;DR: In this paper , the effects of proton implantation doping on transparent nanoscale thin films of polyaniline emeraldine base covalently fabricated on organosilanized surfaces were investigated.
References
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TL;DR: In this paper, the basic physical processes involved in the nucleation and growth of thin films of materials on solid surfaces are described, and the relationships between the thermodynamics of adsorption and the kinetics of crystal growth are explored in general terms.
Abstract: The purpose of this article is to describe the basic physical processes involved in the nucleation and growth of thin films of materials on solid surfaces. In this introduction the three modes of crystal growth which are thought to occur on surfaces in the absence of interdiffusion are described, and the relationships between the thermodynamics of adsorption and the kinetics of crystal growth are explored in general terms. This is followed by a brief review of atomistic nucleation theory, explaining the relations of such theories to experimental observables. In the next three sections, recent experimental examples of these three growth modes are given, which are interpreted where possible in terms of nucleation and growth theory. The last section discusses observations on the shapes of growing crystallites and the relation of such observations to nucleation and surface diffusion processes.

2,456 citations

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TL;DR: It is demonstrated that high-quality nanofibers can be readily produced in bulk quantity using the conventional chemical oxidative polymerization of aniline, and a range of new useful functionalities are developed.
Abstract: Known for more than 150 years, polyaniline is the oldest and potentially one of the most useful conducting polymers because of its facile synthesis, environmental stability, and simple acid/base doping/dedoping chemistry. Because a nanoform of this polymer could offer new properties or enhanced performance, nanostructured polyaniline has attracted a great deal of interest during the past few years. This Account summarizes our recent research on the syntheses, processing, properties, and applications of polyaniline nanofibers. By monitoring the nucleation behavior of polyaniline, we demonstrate that high-quality nanofibers can be readily produced in bulk quantity using the conventional chemical oxidative polymerization of aniline. The polyaniline nanostructures formed using this simple method have led to a number of exciting discoveries. For example, we can readily prepare aqueous polyaniline colloids by purifying polyaniline nanofibers and controlling the pH. The colloids formed are self-stabilized via el...

906 citations

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TL;DR: In this article, a review of the low temperature plasma research community that has successfully addressed such issues, through plasma and surface diagnostics and modelling, in semiconductor processing and diamond thin film growth is presented.
Abstract: Carbon nanotubes (CNTs), due to their unique electronic and extraordinary mechanical properties, have been receiving much attention for a wide variety of applications. Recently, plasma enhanced chemical vapour deposition (PECVD) has emerged as a key growth technique to produce vertically-aligned nanotubes. This paper reviews various plasma sources currently used in CNT growth, catalyst preparation and growth results. Since the technology is in its early stages, there is a general lack of understanding of growth mechanisms, the role of the plasma itself, and the identity of key species responsible for growth. This review is aimed at the low temperature plasma research community that has successfully addressed such issues, through plasma and surface diagnostics and modelling, in semiconductor processing and diamond thin film growth.

808 citations

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TL;DR: The term "PdNP catalysis of C-C coupling" used in this review refers to this function of PdNPs as precursors of catalytically active Pd species (i.e., the PdnPs are precatalysts of C -C coupling reactions).
Abstract: Pd catalysis of C-C bond formations is briefly reviewed from the angle of nanoparticles (NPs) whether they are homogeneous or heterogeneous precatalysts and whether they are intentionally preformed or generated from a Pd derivative such as Pd(OAc)2. The most studied reaction is the Heck coupling of halogenoarenes with olefins that usually proceeds at high temperature (120-160 degrees C). Under such conditions, the PdII precursor is reduced to Pd0, forming PdNPs from which Pd atom leaching, subsequent to oxidative addition of the aryl halide onto the PdNP surface, is the source of very active molecular catalysts. Other C-C coupling reactions (Suzuki, Sonogashira, Stille, Negishi, Hiyama, Corriu-Kumada, Ullmann, and Tsuji-Trost) can also be catalyzed by species produced from preformed PdNPs. For catalysis of these reactions, leaching of active Pd atoms from the PdNPs may also provide a viable molecular mechanistic scheme. Thus, the term "PdNP catalysis of C-C coupling" used in this review refers to this function of PdNPs as precursors of catalytically active Pd species (i.e., the PdNPs are precatalysts of C-C coupling reactions).

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Frequently Asked Questions (1)
Q1. What have the authors contributed in "A multi-step cold plasma process for fine tuning of polymer nanostructuring" ?

The innovative plasma process, developed in this study for highly structured surfaces, consists to gradually decrease the input power during deposition in order to form polymer nuclei while preserving monomer structure. This requires studying the high-power step through the value of the power, its duration and the number of steps.