H. P. Jennissen

University of Duisburg-Essen, Essen, North Rhine-Westphalia, Germany

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Publications (110)211.16 Total impact

  • H. P. Jennissen
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    ABSTRACT: A general mathematical form for contact angles on surfaces is suggested, offering fundamental new insights into describing wettability phenomena, which may be of considerable relevance to many fields of science. It was found that the Young equation – although physically well understood on ideal surfaces – is not unique, but a special case of a more general fundamental equation based on complex contact angles, comprising wettability on both ideal and non-ideal surfaces. The novel mathematical form predicts the existence of imaginary contact angles on all non-ideal surfaces, implying two dimensions of wettabilty and necessitating the experimental determination of real and imaginary contact angles. It could be demonstrated that the new equation can be successfully applied to experimental physical and biomedical data in the hydrophilic and hydrophobic range, with novel information gained on non-ideality in the form of complex and imaginary contact angles.Eine allgemeine mathematische Form für Kontaktwinkel auf Oberflächen wird vorgeschlagen, die grundlegende neue Erkenntnisse zur Beschreibung der Benetzbarkeit bietet und von erheblicher Bedeutung für viele Wissenschaftsbereiche sein könnte. Es wurde gefunden, dass die Young Gleichung – obwohl physikalisch auf idealen Oberflächen gut verstanden – nicht einzigartig, sondern ein Sonderfall einer allgemeineren grundlegenden Gleichung komplexer Kontaktwinkel ist, welche die Zusammenführung der Benetzbarkeit auf idealen und nicht-idealen Oberflächen beschreibt. Die neue mathematische Form sagt die Existenz imaginärer Kontaktwinkel auf allen nicht-idealen Oberflächen voraus. Sie impliziert zwei Dimensionen in der Benetzbarkeit, und somit die Notwendigkeit zur experimentellen Bestimmung reeller und imaginärer Kontaktwinkel. Es konnte demonstriert werden, dass die neue Gleichung erfolgreich auf experimentelle physikalische und biomedizinische Daten im hydrophilen und hydrophoben Bereich angewendet werden kann und neue Informationen zur Nicht-Idealität in Form komplexer und imaginärer Kontaktwinkel liefert.
    Materialwissenschaft und Werkstofftechnik 11/2014; 9999(11). DOI:10.1002/mawe.201400296 · 0.43 Impact Factor
  • PolyMerTech 2014, Merseburg, Germany; 06/2014
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    Journal of Tissue Engineering and Regenerative Medicine 06/2014; 8(1):432. DOI:10.13140/2.1.1455.6808 · 4.43 Impact Factor
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    Journal of Tissue Engineering and Regenerative Medicine 06/2014; 8(1):429. DOI:10.13140/2.1.4732.4809 · 4.43 Impact Factor
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    T Sänger, AS Asran, M Laub, GHMichler, HP Jennissen
    Journal of Tissue Engineering and Regenerative Medicine 06/2014; 8(1):458. DOI:10.13140/2.1.4077.1206 · 4.43 Impact Factor
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    POLYCHAR 22 World Forum on Advanced Materials 7-11 April 2014, Stellenbosch, South Africa; 04/2014
  • S Lüers, M Laub, A Kirsch, H P Jennissen
    Biomedizinische Technik/Biomedical Engineering 09/2013; DOI:10.1515/bmt-2013-4105 · 2.43 Impact Factor
  • T Sänger, M Laub, H P Jennissen
    Biomedizinische Technik/Biomedical Engineering 09/2013; DOI:10.1515/bmt-2013-4084 · 2.43 Impact Factor
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    H P Jennissen, S Madenci, S Lüers, M Laub
    Biomedizinische Technik/Biomedical Engineering 09/2013; DOI:10.1515/bmt-2013-4070 · 2.43 Impact Factor
  • S. Lüers, C. Seitz, M. Laub, H.P. Jennissen
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    ABSTRACT: This chapter contains sections titled: Introduction Theoretical Considerations Materials and Methods Results and Discussion Conclusion
    Advances in Contact Angle, Wettability and Adhesion, 08/2013: pages 155-172; , ISBN: 9781118472927
  • K Zurlinden, M Laub, D-S Dohle, H P Jennissen
    Biomedizinische Technik/Biomedical Engineering 08/2012; DOI:10.1515/bmt-2012-4416 · 2.43 Impact Factor
  • H P Jennissen, S Lüers, M Laub
    Biomedizinische Technik/Biomedical Engineering 08/2012; DOI:10.1515/bmt-2012-4464 · 2.43 Impact Factor
  • H. P. Jennissen
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    ABSTRACT: The complete wetting of rough surfaces is only poorly understood, since the underlying phenomena can neither be described by the Cassie-Baxter nor the Wenzel equation. An experimental accessiblility by the sessile drop method is also very limited. The term superhydrophilicity was an attempt to understand the wetting of rough surfaces, but a clear definition is still forthcoming, mainly because non-superhydrophilic surfaces can also display a contact angle of zero. Since the Wilhelmy balance is based on force measurements, it offers a technology for obtaining signals during the whole wetting process. We have obtained evidence that additional forces occur during the complete wetting of rough surfaces and that mathematically contact angles for a hydrophilicity beyond the contact angle of zero can be defined by imaginary numbers. A hydrophilized TPS-surface obtained by chemical wettability switching from a superhydrophobic surface has been previously characterized by dynamic imaginary contact angles of 20i degrees 21i degrees and near-zero hysteresis. Here an extremely high wetting rate is demonstrated reaching a virtual imaginary contact angle of TV,Adv > 3.5i degrees in less than 210 ms. For a rough surface displaying imaginary contact angles and extremely high wetting rates we suggest the term hyperhydrophilicity. Although, as will be shown, the physical basis of imaginary contact angles is still unclear, they significantly expand our methodology, the range of wettability measurements and the tools for analyzing rough hydrophilic surfaces. They may also form the basis for a new generation of rationally constructed medicinal surfaces.
    Materialwissenschaft und Werkstofftechnik 08/2012; 43(8). DOI:10.1002/mawe.201200961 · 0.43 Impact Factor
  • H. P. Jennissen
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    ABSTRACT: Although Wilhelmy balance measurements have been reported to yield undefined values of the type cos θ > 1, this phenomenon often goes unnoticed because commercial instruments fail to report this error, listing a contact angle of zero instead. On rough superhydrophilic surfaces such “undefined” values appear much more frequent, but a mathematical framework for evaluation and quantification is lacking. A solution to the problem of cos θ > 1 was found by implementing the imaginary number i. It will be shown that both the classical and novel contact angles can be described by numbers in an imaginary space hitherto not accessible to the Wilhelmy and Young equation system. It will be exemplified that Wilhelmy balance data classed as undefined because of cos θ > 1, can easily be converted to imaginary numbers allowing the extrapolation of a novel imaginary advancing θai,AH2O = 0.36i rad and receding contact angle θai,RH2O = 0.37i rad at zero immersion depth as in classical tensiometry. The two imaginary angles compare to classical angles of ∣20°∣–∣25°∣ . The postulated core wettability range for superhydrophilicity in the special case of the “inverse lotus effect” is suggested to extend from the classical angle of cos (10°) to the imaginary angle of cos (0.37i rad). Knowledge obtained from such analyses should be of use in constructing novel artificial surfaces of extreme wettability, e. g. superhydrophilicity, not only in the medical field of implantology but also in chemistry, physics and engineering.Obwohl es seit langem Berichte über Wilhelmy-Waage Messungen gibt, die zu undefinierten Werten der Art cos θ > 1 führten, wird dieses Phänomen häufig übersehen, weil die kommerziellen Geräte statt einer Fehlermeldung den Kontaktwinkel Null ausgeben. Auf rauhen superhydrophilen Oberflächen scheinen “undefinierte” Werte sehr viel häufiger vorzukommen als bisher bekannt, wobei ein mathematisches Gerüst für eine Auswertung und Quantifizierung fehlt. Eine Lösung des Problems cos θ > 1 wurde durch die Verwendung der imaginären Zahl I gefunden. Es wird gezeigt, dass sowohl die klassischen als auch neuartige Kontaktwinkel durch Zahlen im imaginären Raum, für den es bisher für die Wilhelmy- und Young-Gleichung keinen Zugang gab, beschrieben werden können. In einem Beispiel wird gezeigt, dass Wilhelmy-Waage Daten, die bisher wegen cos θ > 1 als undefiniert galten, leicht in imaginäre Zahlen konvertiert werden können, die es erlauben einen neuartigen imaginären Vorrück- θai,AH2O = 0.36i rad und Rückzugswinkel θai,RH2O = 0.37i rad bei der Eintauchtiefe Null zu extrapolieren wie bei der klassischen Tensiometrie. Die beiden Winkel sind vergleichbar den klassischen Winkeln von ∣20°∣–∣25° ∣ . Der postulierte Kernbereich für die Benetzbarkeit im Spezialfall des “inversen Lotus-Effektes” erstreckt sich vom klassischen Kontaktwinkel cos (10°) bis zum imaginären Winkel von cos (0.37i rad). Neue Erkenntnisse, die von solchen Analysen gewonnen werden können, sollten von Bedeutung für die Herstellung neuer künstlicher Oberflächen mit extremer Benetzbarkeit z.B. Superhydrophilizität nicht nur im Medizinischen Bereich der Implantologie sondern auch in der Chemie, Physik und den Ingenieurwissenschaften sein.
    Materialwissenschaft und Werkstofftechnik 12/2011; 42(12). DOI:10.1002/mawe.201100920 · 0.43 Impact Factor
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    H.P. Jennissen, S. Lüers
    Materialwissenschaft und Werkstofftechnik 04/2011; 42(4). DOI:10.1002/mawe.201190016 · 0.43 Impact Factor
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    H. P. Jennissen
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    ABSTRACT: Ultra-hydrophilic titanium surfaces can be prepared in a variety of ways by acid etching. However such surfaces are unstable in air and in water so that a storage for several years, as is necessary for clinical use, is a major problem. Ultrahydrophilic surfaces on miniplates prepared by chromosulfuric acid (CSA) enhancement showing dynamic advancing and receding contact angles of 0 degrees (no hysteresis) can be easily stabilized and stored at room temperature in the dry state in air atmosphere. After evaporation of the aqueous phase of a salt containing solution (e.g. PBS) an exsiccation layer composed of specific ions is formed on the dry metal oxide surface exerting the stabilizing effect. The mechanism involved in this stabilizing effect of salts appears to be governed by the Hofmeister Effect. Ultra-hydrophilic CSA (chromsulfuric acid) etched surfaces can be stabilized by an exsiccation layer for over 3 years without loss of hydrophilicity.
    Materialwissenschaft und Werkstofftechnik 04/2011; 42(4). DOI:10.1002/mawe.201190014 · 0.43 Impact Factor
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    ABSTRACT: A functionalization is required for calcium phosphate-based bone substitute materials to achieve an entire bone remodeling. In this study it was hypothesized that a tailored composite of tricalcium phosphate and a bioactive glass can be loaded sufficiently with rhBMP-2 for functionalization. A composite of 40 wt% tricalcium phosphate and 60 wt% bioactive glass resulted in two crystalline phases, wollastonite and rhenanite after sintering. SEM analysis of the composite's surface revealed a spongious bone-like morphology after treatment with different acids. RhBMP-2 was immobilized non-covalently by treating with chrome sulfuric acid (CSA) and 3-aminopropyltriethoxysilane (APS) and covalently by treating with CSA/APS, and additionally with 1,1'-carbonyldiimidazole. It was proved that samples containing non-covalently immobilized rhBMP-2 on the surface exhibit significant biological activity in contrast to the samples with covalently bound protein on the surface. We conclude that a tailored composite of tricalcium phosphate and bioactive glass can be loaded sufficiently with BMP-2.
    Journal of Materials Science Materials in Medicine 02/2011; 22(4):763-71. DOI:10.1007/s10856-011-4252-4 · 2.38 Impact Factor
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    ABSTRACT: The main objectives of the study described below were of two-fold nature: (1) to examine if rhBMP-2-biocoated implants in a pig model could lead to ectopic bone formation and (2) if quantitative and/or qualitative differences could be found between adhesively and covalently bonded BMP II using the scintigraphic method. In order to examine these central questions, 26 Göttingen minipigs were allocated to three groups with a control group (n=7) and two study groups (n=9 each) receiving one of three implant types: (a) chromosulfuric acid treated titanium surface as control, (b) non-covalently bonded BMP-2, and (c) covalently bonded and immobilized rhBMP-2. Each animal received four barbell-shaped implants, one in the proximal and distal metaphysis of each femur. The scintigraphic analyses were conducted after four, eight, and 12 weeks postoperatively. The visual (qualitative) analysis failed to show ectopic bone formation in any of the three groups. The statistical analysis of the relative values for bone formation yielded no significant differences between the groups, although the limitation in the applied methods do not enable one to draw conclusions regarding the histomophometric results.
    Biomedicine & pharmacotherapy = Biomedecine & pharmacotherapie 02/2011; 65(1):63-8. DOI:10.1016/j.biopha.2010.10.008 · 2.11 Impact Factor
  • MRS Online Proceeding Library 01/2011; 676. DOI:10.1557/PROC-676-Y3.14
  • H.P. Jennissen
    [Show abstract] [Hide abstract]
    ABSTRACT: Ultra-hydrophilic titanium surfaces can be prepared in a variety of ways by acid etching. However such surfaces are unstable in air and in water so that a storage for several years, as is necessary for clinical use, is a major problem. Ultrahydrophilic surfaces on miniplates prepared by chromosulfuric acid (CSA) enhancement showing dynamic advancing and receding contact angles of 0° (no hysteresis) can be easily stabilized and stored at room temperature in the dry state in air atmosphere. After evaporation of the aqueous phase of a salt containing solution (e. g. PBS) an exsiccation layer composed of specific ions is formed on the dry metal oxide surface exerting the stabilizing effect. The mechanism involved in this stabilizing effect of salts appears to be governed by the Hofmeister Effect. Ultra-hydrophilic CSA (chromsulfuric acid) etched surfaces can be stabilized by an exsiccation layer for over 3 years without loss of hydrophilicity.Ultra-hydrophile Titanoberflächen können auf verschiedenen Wegen gewonnen werden. Diese Oberflächen verlieren jedoch sowohl in der Luft als auch in Wasser ihre ultra-hydrophilen Eigenschaften, wodurch die Lagerung über mehrere Jahre, wie sie für Implantate notwendig ist, zum Problem wird. Ultrahydrophile Oberflächen auf Titanplättchen, die mit Chromschwefelsäure (CSA) veredelt wurden und dynamische Vorrück- und Rückzugswinkel von 0 Grad (keine Hysterese) aufweisen, können leicht im trockenen Zustand bei Zimmertemperatur in Luftatmosphäre stabilisiert und gelagert werden. Nach Evaporierung der wässrigen Phase einer Salzlösung (z. B. PBS) bildet sich auf der Metalloberfläche eine Exsikkationsschicht bestehend aus einer spezifischen Ionenzusammensetzung, die den stabilisierenden Effekt hervorruft. Der zugrunde liegende Mechanismus für die Stabilisierung von Exsikkationsschichten scheint im Hofmeister-Effekt zu liegen. Ultra-hydrophile CSA (Chromschwefelsäure) geätzte Oberflächen können durch eine Exsikkationsschicht für 3 Jahre stabilisiert und gelagert werden ohne Hydrophilizitätsverlust.
    Materialwissenschaft und Werkstofftechnik 12/2010; 41(12). DOI:10.1002/mawe.201000705 · 0.43 Impact Factor

Publication Stats

1k Citations
211.16 Total Impact Points

Institutions

  • 1989–2014
    • University of Duisburg-Essen
      Essen, North Rhine-Westphalia, Germany
  • 1994–2011
    • University Hospital Essen
      • Institute of Physiological Chemistry
      Essen, North Rhine-Westphalia, Germany
  • 2000
    • Universität Heidelberg
      • Department of Orthopedics and Traumatology
      Heidelberg, Baden-Wuerttemberg, Germany
  • 1999
    • University of Utah
      • Department of BioEngineering
      Salt Lake City, Utah, United States
  • 1978–1993
    • Ruhr-Universität Bochum
      • • Department of Biochemistry Supramolecular Systems
      • • Institut für Physiologische Chemie
      Bochum, North Rhine-Westphalia, Germany
  • 1985–1989
    • Ludwig-Maximilian-University of Munich
      • Institute of Chinese Studies
      München, Bavaria, Germany
  • 1987
    • University of Tuebingen
      Tübingen, Baden-Württemberg, Germany
  • 1974
    • University of Wuerzburg
      • Institute for Physiology
      Würzburg, Bavaria, Germany