Recent research demonstrating plasma treatment of powders ‎with in-line plasma

Plasma treatment of powders

Feature Article - Plasma treatmnent of powders

Great article on the recent research demonstrating plasma treatment of powders ‎with in-line plasma

Read an excerpt from the article below:

Atmospheric Plasma Surface Modification of PMMA and PP Micro-Particles
Mary Gilliam,* Susan Farhat, Ali Zand, Barrack Stubbs, Michael Magyar, Graham Garner

Chemical surface modification of polymethylmethacrylate (PMMA) and polypropylene (PP) particles was achieved using a continuous atmospheric plasma process, resulting in increased oxidation and hydrophilicity. Contact angles of treated PMMA ranged from 79–1178 (1258 for untreated). Air plasma produced higher contact angles than pure nitrogen, which is attributed to primary surface degradation from oxygen. Higher energy and flow rate of water resulted in decreased contact angles. Treated PP mixed in water upon agitation, while untreated PP remained at the surface. X-ray photoelectron spectroscopy (XPS) showed increased C—O and C55O for treated samples. The addition of 10% hydroxyethylmethacrylate (HEMA) to water showed a slight decrease in contact angle, but no difference from pure water in XPS results.

1. Introduction

Polymer micro-sized particles and spheres are widely used in paints and coatings, adhesives, composites, pharmaceuticals, medical diagnostics, biotechnology, cosmetics, and more. [1–6]

Surface properties are often times important for the successful application of materials. Chemical modification on the surface of polymer particles can improve compatibility with surrounding media, such as hydrophilicity in aqueous media, or impart a desired functionality or surface property. For example, polymer microspheres, such as polystyrene, have been surface m odified for biomolecule attachment and used in optical tweezers for DNA manipulation. [5,6]

Surface functionalization through traditional chemical means, such as graft polymerization or exposure to reactive chemicals, is often time-intensive and produces significant amount of waste for disposal. Plasma discharges have been used for many decades to chemically modify the surfaces of polymers by surface functionalization as an effective process with little waste products. [7–12]

More recently, atmospheric, non-equilibrium plasmas have been applied for polymer surface modification. [13–17]

Plasma surface modification processes have been applied to rigid plastic parts, sheets, and films for purposes of increasing wettability, enhancing adhesion, and increasing compatibility with a chemical or contacting material in subsequent processes and the final application.

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Atmospheric Plasma Surface Modification of PMMA and PP Micro-Particles

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Automotive Industry Experts order further Plasma Treatment System from Henniker

IAC International Automotive Industry Experts opt for plasma treatment system

IAC International Automotive Components Logo

Automotive Industry Experts IAC Group are a leading global supplier of automotive interior components and systems serving all of the multinational automotive OEMs.

We are pleased to announce that after trouble free working of their first plasma system from Henniker, that IAC Group have ordered a 2nd unit to meet increased production demand.

Plasma Treatment in the Automotive Industry

A close up view of a car headlight

Plasma treatment equipment and plasma surface treatment processes are used to improve the adhesion of a wide range of interior and exterior automotive parts without the heat issues that can be common with flame treaters.

Both in-line and vacuum plasma systems are effectively deployed to increase the surface wettability of common automotive materials such as ABS, LGF-PP and PC amongst others. Henniker is recognised as a leader in the field having worked with many leading suppliers both in the UK and overseas to deliver on-time and in-budget plasma systems for almost every common automotive manufacturing task.

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Interesting application of plasma treatment of modern sportswear

Plasma treatment of modern sportswear

Feature Article - Plasma treatment of modern sportswear

Interesting application of plasmas to modern sportswear

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Production scale plasma modification of polypropylene baselayer for improved water management properties

Gulnara Fauland, Floriana Constantin, Hossain Gaffar, Thomas Bechtold; Research Institute of Textile Chemistry and Textile Physics, Leopold-Franzens-University Innsbruck, Hochsterstraße 73 A-6850, Dornbirn, Austria
V-Trion GmbH, Schwefelbadstrasse 2, A-6845, Hohenems, Austria Leopold-Franzens-University Innsbruck is a member of EPNOE—European Polysaccharide Network of Excellence, www.epnoe.eu
Gulnara Fauland undertook analytical characterization and material testing, Floriana Constantin undertook data interpretation and article revision, Hossain Gaffar undertook the full scale plasma processing and Thomas Bechtold planned the experimental design, contributed to data interpretation, and article preparation. Correspondence to: T. Bechtold (E-mail: Thomas.Bechtold@uibk.ac.at)

 

ABSTRACT:
Through its hydrophobic properties, polypropylene (PP) offers unique potential as a functional fiber for a wide range of applications, for example, in nonwovens for hygiene applications or as a   baselayer in sports textiles. Current work is focused on the modification of PP presently used in baselayers for sports textiles to increase the hydrophilicity by use of a production scale plant for low pressure plasma treatment. Attention was directed toward an increase in hydrophilicity and time stability of the achieved modification during storage. Changes in the fabric were characterized by sorption of the cationic dye (methylene blue), water retention value, water transport properties, Fourier transform infrared spectroscopy and color measurement. The obtained results indicate an improved wettability and wicking. The extent of modification decreased wi th storage time and parallel yellowing of treated samples was observed. This indicates chemical rearrangement of the  products initially formed on the fiber surface.
VC 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41294. Received 31 May 2014; accepted 11 July 2014 DOI: 10.1002/app.41294

 

KEYWORDS:
  • manufacturing
  • properties and characterization
  • textiles
INTRODUCTION
Lightweight fabrics that form polypropylene (PP) hold a specific position in the design of functional sport s clothing. Favorable transport and cooling properties can be achieved when the hydrophobic
PP is used as a baselayer and the fabric is in direct contact with the skin. Good mechanical and chemical properties such as low specific weight (0.91 g cm 23), high fiber strength (42–53 cN tex 21) and
good resistance to acids and alkali make the material well suited for textile production. However, the low surface energy (28–30 mN m 21) of the hydrocarbon polymer results in poor wettability (0.05% at 20C) and difficult wet processing in textile dyeing and finishing. 1The low surface energy forms the physical basis for the application of PP as a functional fiber; W ith low binding capacity for sweat, PP demonstrated its almost unique ability to spread sweat between the skin and the baselay er PP-fabric. Thus, PP based materials are widely used as functional baselayers, which exhibit high cooling capacity and rapid drying properties.
Improved, spontaneous distribution of sweat between the skin and fabric from the modification of the surface properties of the PP-fabric to increase surface energy would be desirable. Scientific models for sweat transportation and drying of PP baselayer fabrics show that modification of the fiber toward more hydrophilic behavior could lead to further improvement in functionality.
As a result of the low polarity of PP-fibers and limited temperature stability options for wet textile processing in aqueous media is rather limited, for example, technical dyeing or chemical modification of PP in aqueous media still require improved solutions. Thus, plasma processing of PP-based materials has been studied extensively, as this dry process can be used to achieve a wide range of surface modifications. 2,3 The influence of different process gases in the plasma atmosphere on the hydrophilization of PP-nonwovens has been reported in the literature.
Additional Supporting Information may be found in the online version of this article. VC 2014 Wiley Periodicals, Inc.

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Production scale plasma modification of polypropylene baselayer for improved water management properties

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Composites Innovation Cluster celebrates its first year

Composites Innovation Cluster celebrates its first year

CiC Composites Innovation Cluster Logo

The Composites Innovation Cluster (CiC), funded by the UK Government’s Advanced Manufacturing Supply Chain Initiative (AMSCI), is celebrating its one-year mark.

The CiC comprises of 15 projects with 28 partners and aims to bring academics, suppliers, and primes together with the strategy of the National Composites Centre to support the delivery of a nationally connected network of materials specialists, manufacturing and process businesses, tooling and systems providers.

Supporting project partners

Terry Whitmore, Managing Director of Henniker Scientific, said: “Our involvement in the CiC has raised our profile within the UK composites community quite significantly. This has generated direct business for us and has also helped us to gain a much better understanding of the specific challenges facing the composites community, enabling us to develop specific plasma treatment processes ahead of our competitors.”

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Henniker appearing at the Advanced Composites Engineering Show 2014, with live treatments

Advanced Composites Engineering Show

Event News - Advanced Composites Engineering Show 2014

We are recognised as the UK’S premier organisation involved in the plasma treatment of composite materials. We offer a range of composite specific plasma equipment and surface treatment processes, some of which have been developed in collaboration with leading members of the UK Composites supply chain as part of our involvement in the CiC initiative. We also offer free proof of concept trial service, rental systems and comprehensive surface testing facilities. Visit us at the Advanced Composites Engineering Show to learn more.

Composites Engineering Show 2014

In 2013 we were invited to be part of the Composites Innovation Cluster, investigating the plasma treatment of composite materials as part of the UK government’s £120 million Advanced Manufacturing Supply Chain Initiative.

This strong research and development focus is a core part of the business, the results of which ultimately benefit our industrial customer base and help set us apart from our competitors.

find out more of our involvement in the Composites Innovation Cluster

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Plasma Cleaning for UHV Applications: Particle Accelerators

Case Study  |  Activation of surfaces for biomedical applications

Company: Daresbury Laboratory| Region: UK | Sector: Laboratory  Research & Development
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Plasma Cleaning for UHV Applications: Hyper-clean Surfaces

Daresbury Laboratories Accelerator Ring with a scientisit present

UHV critical components, such as those used extensively in surface science laboratories and particle accelerators, are required to meet strict cleanliness criteria of which pre-installation cleaning is an important step.

Daresbury Laboratory , based in the UK and a centre for worldwide particle accelerator technology, approached Henniker Plasma to look at the potential of oxygen plasma cleaning as part of the stringent pre-cleaning process. Plasma cleaning was assessed by measurement of electron stimulated desorption yields. Together, we were then able to compare the results from using traditional solvent based cleaning together with plasma cleaning.


Solvent Cleaning Technique

A hydrofluoroether (HFE) type solvent was employed at Daresbury Laboratory as the primary cleaning solvent of choice, having been chosen from the outcome of earlier studies of the effects of  various cleaning techniques on outgassing and electron stimulated desorption from stainless steel [1].
The steps used in the HFE procedure are as follows;
  • Manual detergent wash
  • Rinse in de-mineralised water
  • 15 minutes aqueous wash using standard
  • detergent
  • Rinse in de-mineralised water
  • 15 minute ultrasonic clean in HFE
  • 15 minute vapour clean in HFE
  • Rinse in de-mineralised water
  • Dry in oven (80°C)

Plasma Cleaning

When gas atoms are ionised, the collision of high energy particles knocks electrons out of their orbits. This results in the characteristic “glow” or light associated with plasma. Plasmas contain many different species including atoms, molecules, ions, electrons, free radicals, metastables, and photons in the short wave ultraviolet (vacuum UV or VUV) range. Plasmas are generated in closed vessels at low pressures, typically < 1.0 Torr. The low pressure results in a long mean free path of the plasma species, so that they remain reactive until contact with a surface. The overall chamber temperature
at the commonly used power levels and pressures is close to room temperature.
The gas used in these experiments was oxygen. The VUV energy is effective in breaking the organic  bonds (i.e., C-H, C-C, C=C, C-O, and C-N) of surface contaminants. This helps to break apart high molecular weight contaminants. A second cleaning action is carried out by the oxygen species created in the plasma (O2+, O2-, O3, O, O+, O-, ionised ozone, metastably-excited oxygen, and free electrons). These species react with organic contaminants to form H2O, CO, CO2, and lower molecular weight hydrocarbons. These compounds have relatively high vapour pressures and are easily evacuated from the chamber.

Measurement of Sample Cleanliness

Stainless steel samples were first contaminated with a variety of contaminants including oils, grease, fingerprints and marker pen.
Sample cleanliness was then assessed by measuring the electron stimulated desorption yield, calculated by the throughput at the conductance:-

CCLRC Equation

Where Nm= number of desorbed molecules, Ne= number of incident electrons,  qe = electron charge, kB = Boltzmann’s constant, T = chamber temperature,  Iesd = drain current, Q = throughput.


Other essential features of the experiment were:

  • Cylinder biased to +200V
  • Coaxial electron source
  • Variable conductance: 143 ltr.sec-1 (mass 28) for ESD
  • Calibrated pressure measurement
  • Sample drain current measured
  • during ESD

Figure-1. Daresbury Lab

Results and Discussion

The results shown in Chart 1 demonstrate that there is a clear improvement in electron stimulated desorption yield (sample cleanliness) when plasma cleaning is used in addition to the solvent cleaning procedure described. The measured electron stimulated desorption yield with the additional plasma cleaning step is almost the same as the yield from the uncontaminated samples. For this specific work this result suggests that plasma cleaning could add benefits to vacuum components used in an accelerator environment due to the reduction in desorption yield and hence a smaller gas load to contend with.

The results of samples subjected to a reduced cleaning cycle in conjunction with plasma cleaning (ultrasonic HFE + plasma) are also better than the results obtained from the samples that had undergone the full HFE cleaning process. This suggests that the full HFE cleaning process could be reduced to just two stages, ultrasonic and plasma, and still produce samples of  higher cleanliness.
The remaining samples (aqueous or vapour clean + plasma) all show similar results in that they are insufficient combinations of cleaning steps to produce UHV clean samples.

 


Our Solution
Using our bench-top plasma cleaner in combination with the traditional solvent based cleaning routine described here produced cleaner surfaces, similar to those of uncontaminated surfaces, than solvent based cleaning alone.  This example demonstrates that Plasma cleaning can
i)    Reduce lengthy cleaning processes
ii)    Reduce the use of environmentally unfriendly solvents
iii)    Reduce the costs associated with handling, use and disposal of solvent based cleaners.

The Daresbury Laboratories team worked closely with Henniker Plasma to ensure a solution which enhanced and  determined their own objective in becoming a worldwide leader in particle accelerator technology.

Daresbury results graph

Chart 1

Reference
[1]  K.J. Middleman, Vacuum 81 (2007) P793-798.

 

“Using our bench-top plasma cleaner in combination with the traditional solvent based cleaning routine described here produced cleaner surfaces,
than solvent based cleaning alone.”

K.J. Middleman, Daresbury Laboratory

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Plasmas & Micro Fuel Cell Application

Plasmas & Micro Fuel Cell Application

Feature Article: Plasmas & Micro Fuel Cell Application

See how plasmas are being used to help drive research in novel micro-fuel cell applications.

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Single Step Plasma Deposition of Platinum-Fluorocarbon Nanocomposite Films as Electrocatalysts of Interest for Micro Fuel Cells Technology

Single Step Plasma Deposition of Platinum Fluorocarbon Nanocomposite Films as Electrocatalysts of Interest for Micro Fuel Cells Technology Antonella Milella,* Fabio Palumbo,* Elena Dilonardo, Gianni Barucca, Pinalysa Cosma, Francesco Fracassi
Courtesy of Plasma Process. Polym. 2014, 11, 1068–1075, ß 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim1068

 

In this paper, we present a one step plasma based approach for the deposition of Pt-fluorocarbon nanocomposite films as electrocatalysts in hydrogen-based micro fuel cells. Results show that the chemical and morphological struc ture of the film can be tuned by controlling the power delivered to the plasma, and the gas feed composition. Platinum is included in the film in metallic form and its content can be continuously varied from a few atomic percent to 86%. The metal is embedded in the film as crystalline nanoclusters of size below 10 nm, uniformly distributed across the sample.

Film catalytic activity, in terms of hydrogen oxidation reaction, has been tested by cyclovoltammetry and it increases with the Pt loading, with a maximum specific electrochemical surface area of 94 cm 2 mg 1, for film deposited on flat glassy carbon.

1. Introduction

Proton exchange membrane(PEM) fuel cells are devices able to provide electricity with virtually zero emissions. In hydrogen based fuel cells, the oxidation of H 2 occurs at the anode while O 2 is reduced at the cathode. Both these reactions heavily rely on the use of a catalyst, with Pt generally being the most effective one. [1–3]

The overall reaction is then the recombination of molecular hydrogen and oxygen which produces water and energy. The core of a PEM fuel cell is the membrane electrode assembly (MEA), which consists of a proton conductive membrane sandwiched between two catalytic electrodes. Nanoparticles of platinum and its alloys, supported on conductive porous carbonaceous substrates, are mainly used as catalyst, while Nafion 1, a perfluorosulfonic polymer, as proton conductive material. In the common ‘‘stack’’ configuration, a PEM fuel cell is made of a membrane hot pressed between the two electrodes and combined in series with other cells via bipolar plates. PEM fuel cells are primarily designed for portable applications, which require lower power outputs (5–50 W), with automotive use being the ultimate objective.

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Single Step Plasma Deposition of Platinum-Fluorocarbon Nanocomposite Films as Electrocatalysts of Interest for Micro Fuel Cells Technology

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Henniker Install State of the Art Automated Atmospheric Plasma Treatment System at Warwick University

Automated Atmospheric Plasma Treatment System supplied to Engineering Materials and Manufacturing Dept (WMG) at Warwick University

University of Warwick - Henniker Plasma - Logo - Testimonial

We are delighted to have been selected to supply our robot controlled, dual nozzle automated atmospheric plasma treatment system to the Engineering Materials and Manufacturing Dept (WMG) at Warwick University. The WMG group aims to design and manufacture the next generation of lightweight solutions in response to the significant challenges facing the UK and global transportation industry as a result of the low carbon agenda. It builds upon a 10 year track record in delivering such solutions to industry through a series of TSB, AWM and ERDF funded collaborative R&D projects. It is materials agnostic, covering metals, ceramics, polymers, composites and hybrids. The primary application focus is in automotive, addressing the UK Automotive Council Lightweight Structures and Powertrain R&D priority.

READ MORE HERE ON THE RESEARCH AND DEVELOPMENT TAKING PLACE AT THIS WORLD CLASS ACADEMIC DEPARTMENT

Atmospheric Plasma Robot System for Surface Treatment

 

 

 

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Plasma Etching of Silk Fibroin Alters Surface Stiffness: A Cell–Substrate Interaction Study

Plasma Etching of Silk Fibroin

Feature article - Plasma etching of silk fibroin

An interaction study where oxygen plasma etching was used to treat silk fibroin (SF). The plasma exposure removed a significant amount of SF but left behind most surface properties close to their original state.

Oxygen Plasma Etching of Silk Fibroin Alters Surface Stiffness: A Cell–Substrate Interaction Study

Keywords:

  • cell–substrate interaction
  • oxygen plasma etching
  • silk fibroin
  • surface stiffness

Oxygen plasma etching was used to treat silk fibroin (SF). The plasma exposure removed a significant amount of SF but left behind most surface properties close to their original state. However, nano-indenter measurements revealed a substantial increase in surface modulus of swollen SF from 62 to 500 kPa. This allowed oxygen plasma etching as a potential tool to investigate the impact of surface stiffness on cell-substrate interaction. Mouse fibroblasts (L929) and human mesenchymal stem cells (hMSC) were employed as distinct model cases. In vitro results revealed that the increased stiffness of plasma-treated SF affected only L929 adhesion, not hMSC. L929 cell attachment and spreading were better on the stiffer surface than the untreated surface, while hMSC could spread well on all SF surfaces.

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Oxygen Plasma Etching of Silk Fibroin Alters Surface Stiffness: A Cell–Substrate Interaction Study

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Electrospun Nanofiber Scaffolds & Plasma Polymerization: A Promising Combination

Electrospun Nanofiber Scaffolds & Plasma Polymerization

Feature Article - Electrospun nanofibre scaffolds & plasma polymerization

A really interesting study on the promising results of combining electrospun nanofiber scaffolds and plasma polymerization towards complete, stable endothelial lining for vascular grafts.

Electrospun Nanofiber Scaffolds and Plasma Polymerization: A Promising Combination Towards Complete, Stable Endothelial Lining for Vascular Grafts

Houman Savoji1,2, Afra Hadjizadeh3,†, Marion Maire1, Abdellah Ajji2,3, Michael R. Wertheimer2,4,* and Sophie Lerouge1,5,* Version of Record online: 17 APR 2014 DOI: 10.1002/mabi.201300545 © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

 In the quest to reduce risk of thrombosis in vascular grafts, it is essential to provide a surface with morphological and mechanical properties close to those of the extracellular matrix beneath the  luminal endothelium, and to favor the growth of a confluent, stable monolayer of endothelial cells. This is accomplished here by combining electrospun poly(ethyleneterephthalate) (PET) mats with an  amine-rich thin plasma-polymerized coating, designated ‘‘L-PPE:N.’’ Its deposition does not modify the open, highly porous mats and leads only to small changes in mechanical properties. L-PPE:N  significantly improves the adhesion and growth of human umbilical vein endothelial cells (HUVEC) and their resistance to flow-induced shear stress. These properties favor the formation of desired  confluent HUVEC monolayers on the topmost surface, unlike conventional vascular grafts (ePTFE or woven PET), where cells migrate inside the material. This combination is therefore highly advantageous for the pre-endothelialization of the luminal side of small-diameter vascular prostheses.

1. Introduction

Cardiovascular diseases are the leading cause o f premature death worldwide, occlusion of blood vessels being a major problem. [1] Autologous grafts from patients’ own veins or arteries can provide a solution when angioplasty or stenting are not feasible, but not when treatment is impeded by previous surgery or antecedent…

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Electrospun Nanofiber Scaffolds and Plasma Polymerization: A Promising Combination Towards Complete, Stable Endothelial Lining for Vascular Grafts

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