Plasma-based introduction of monosort functional groups of different type and density onto polymer surfaces. Part 2: Pulsed plasma polymerization

Friedrich, Jörg; Mix, Renate; Kühn, Gerhard; Retzko, Iris; Schönhals, Andreas; Unger, Wolfgang

doi:10.1163/156855403765826874

Cited by 51 publications

(49 citation statements)

References 29 publications

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“…Samples with a thickness layer of 150 nm were deposited in general. To calculate the thickness from the weight gain, the film density was assumed to be 1 g/cm 3 . This means that the absolute values of the thicknesses might have an error due to the elasticity of the deposited layers but this potential error is essentially smaller than the observed changes.…”

Section: Pulsed Plasma Polymerizationmentioning

confidence: 99%

“…However, the numerous applications of plasma deposition require an optimization of the process to obtain a high degree of preservation of the functional groups of the monomers. It has been shown that pulse plasma polymerization offers a promising option to synthesize plasma polymers with minimized irregularities and a high degree of functionality retention in comparison to continuous techniques [2][3][4]. It was possible to keep the chemical functionality of the monomer in the vapor phase in the condensed film which has an important impact on the strategies employed for applications of plasma polymers [5].…”

Section: Introductionmentioning

confidence: 99%

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Structure of Plasma Poly(Acrylic Acid): Influence of Pressure and Dielectric Properties

Fahmy

Mohamed

Schönhals

2014

Plasma Chem Plasma Process

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Thin poly(acrylic acid) PAA films were deposited by pulsed plasma polymerization on different organic and inorganic substrates. The structure-property relationships of the deposited acrylic acid polymers were studied in dependence on the monomer pressure by various techniques and probes. The surface and bulk properties of the plasma deposited films were investigated by X-ray photoelectron spectroscopy, attenuated total reflection infrared, and broad band dielectric spectroscopy. The experimental infrared frequencies of PAA films are compared with those predicted from quantum mechanical calculation. The concentration of the COOH groups in the film (stored in ambient air) decreased by about 15 % compared to the as-prepared sample. The plasma deposited PAA probably form a highly branched product. However, the dielectric measurements show that in addition to the hydrogen bonds, self condensation process was able to hinder the localized fluctuation as well. These processes lead to form a cross-linked network polymer film. Nevertheless, a low energy is sufficient to break these processes during heating at atmospheric pressure. Therefore, homogenized samples with free branches (functional group) were obtained after a first heating with structures close to conventional polymerized acrylic acid. Thus, a thermally stable product was obtained.

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Section: Pulsed Plasma Polymerizationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Structure of Plasma Poly(Acrylic Acid): Influence of Pressure and Dielectric Properties

Fahmy

Mohamed

Schönhals

2014

Plasma Chem Plasma Process

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“…46,47 This technology has been successfully employed in variety of biomaterial applications. 44,[48][49][50][51] To investigate the influence of types and densities of surface functional groups on foreign body reactions, polypropylene microspheres were coated with varying densities of -OH and -COOH functionalities. After subcutaneous implantation in mice for two weeks, the extent of inflammatory and fibrotic responses to the implants was then evaluated histologically.…”

Section: Introductionmentioning

confidence: 99%

Species and Density of Implant Surface Chemistry Affect the Extent of Foreign Body Reactions

et al. 2008

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Implant-associated fibrotic capsule formation presents a major challenge for the development of long term drug release microspheres and implantable sensors. Since material properties have been shown to affect in vitro cellular responses and also to influence short term in vivo tissue responses, we have thus assumed that the type and density of surface chemical groups would affect the degree of tissue responses to microsphere implants. To test this hypothesis, polypropylene particles with different surface densities of -OH and -COOH groups, along with the polypropylene control (-CH 2 groups) were utilized. The influence of functional groups and their surface densities on tissue reactions were analyzed using a mice subcutaneous implantation model. Our comparative studies included determination and correlation of the extents of fibrotic capsule formation, cell infiltration into the particles and recruitment of CD11b+ inflammatory cells for all of the substrates employed. We have observed major differences among microspheres coated with different surface functionalities. Surfaces with -OH surface groups trigger the strongest responses while -COOH rich surfaces prompt the least tissue reactions. However, variation of the surface density of either functional group has a relatively minor influence on the extent of fibrotic tissue reactions. The present results show that surface functionality can be used as a powerful tool to alter implant-associated fibrotic reactions and, potentially, to improve the efficacy and function of drug delivery microspheres, implantable sensors and tissue engineering scaffolds.

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“…Non‐equilibrium plasmas of volatile organic compounds may be used to deposit ultra‐thin and pinhole‐free films 1–5. These films are commonly referred to as plasma polymers.…”

Section: Introductionmentioning

confidence: 99%

Surface Analysis of Plasma Deposited Polymer Films, 7

Oran

Swaraj

Lippitz

et al. 2006

Plasma Processes & Polymers

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Summary: Plasma deposited allylamine films were studied by “in situ” ToF‐SSIMS, XPS and NEXAFS Spectroscopy before exposure to ambient air. The influence of external plasma parameters such as duty cycle, plasma power, and monomer flow rate on (i) unsaturation, (ii) branching and cross‐linking, (iii) nitrogen surface concentration and (iv) retention of amino groups was investigated. Harder plasma conditions, which can be obtained when high duty cycles, high plasma power, and low monomer flow rates are employed, increase the unsaturated, branched and cross‐linked character of the plasma deposited films, while the surface concentration of N as well as the retention of the monomer's amino group decrease. As proven by NEXAFS findings and cross‐checked by ToF‐SSIMS results, the allylamine monomer's primary amino groups are partially transformed into other nitrogen functionalities during its plasma polymerization. Amongst them imines and nitriles are the conversion products with the highest probabilities of formation. Another conversion channel is the formation of nitrogen species not participating in the film growth. This is the reason for an increased N loss in plasma deposited allylamine films as observed independently by XPS and ToF‐SSIMS when the plasma parameters are changed from mild to hard.

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Plasma-based introduction of monosort functional groups of different type and density onto polymer surfaces. Part 2: Pulsed plasma polymerization

Cited by 51 publications

References 29 publications

Structure of Plasma Poly(Acrylic Acid): Influence of Pressure and Dielectric Properties

Structure of Plasma Poly(Acrylic Acid): Influence of Pressure and Dielectric Properties

Species and Density of Implant Surface Chemistry Affect the Extent of Foreign Body Reactions

Surface Analysis of Plasma Deposited Polymer Films, 7

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