hoffmann

Former Chairholder PC I

Prof. em. Dr. Heinz Hoffmann


Phone: +49 (0)921 507 36 135
heinz.hoffmann@uni-bayreuth.de

Research

During the last years I have been engaged in research in the following areas:

  1. Viscoelastic solutions and phases:
    Such fluids are of interest in cosmetics, in formulations for agrochemicals in detergency as cleaning liquids and as fracture fluids in tertiary oil recovery. Optimised solutions can also be used as drag reducing systems. I have held patents for many surfactant systems as drag reducing fluids already more than 20 years ago.
    I realize that only one type of viscoelastic fluids were used as fracture fluids, namely viscoelastic surfactant solutions with threadlike micelles, the so called L1-phases. However, there are other viscoelastic solutions with different microstructures which might be used as well. I would like to mention here viscoelastic vesicle phases, viscoelastic samples from hydrophobically modified polyelectrolytes, combinations of watersoluble polymer and surfactants and so on. Some of these samples are not mentioned in relevant patents and they probably could be patented. These systems could not only be used as fracture fluids but also as fluids to transport sand or finely milled coals in large pipes.
  2. Emulsions and microfemulsions:
    My group has been engaged in producing emulsions and optimizing the stability of emulsions. Lately we have also worked on the preparation and the properties of microemulsions. These fluids are thermodynamically stable phases which can contain about 50 % oil and 50 % water and a few percent of surfactant. Microemulsions are transparent liquids of low viscosity. They are of particular use in enhanced oil recovery (EOR).
    They are formed from aqueous surfactant solutions and oils when the interfacial tension between the two phases is extremely low (~10-3 mN/m). At present we are preparing such phases for cosmetic industry.
  3. Gel formation and the sol-Gel process: Silicagels and Aerogels:
    In general each solvent or fluid can be gelified. Of particular interest are hydrogels from water or organogels from oils. We can produce both gels with the use of different additives. We have characterized the macroscopic properties of different gels. In the last few years we were engaged with research on silica-gels and on hybrid materials on the basis of silica gels. Wet silica gels can be dried to aerogels while keeping the gel-structures. Under special drying procedure one can obtain large monolithic pieces with dimensions of CM, a density as low as 0.05 g/ml and a surface area of 1000 m2/g. Hybrid materials on the basis of SiO2 are in the center of research in material science around the world. Both bulk materials and thin films can be produced from such compounds. We have been involved in producing antifogging films from the gels.
  4. Cement, mortar and concrete:
    While I cannot be considered a specialist in this area, I have done research in this area and I have realized that with my background on additives I can do useful research to optimize properties of cement. My group was engaged in preparing pore cement where air as small bubbles was entrapped in cement. We were able to produce cement with a density as low as 0.25 g/ml. It is likely that this cement has ideal properties as a thermal insulation material. It remains to be seen what can be done with the novel material that we have produced.
  5. Clays:
    Over many years my group has done basic research with dispersions of clays in combinations with various additives like surfactants and polymers. Such fluids are used as drilling fluids in oil fields. While I have worked on more topics, the mentioned topics are probably the important ones I have worked with.

My co-operations so far have mainly be with chemical companies in Germany and the USA. In the area of cosmetics I still have a co-operation with a Japanese company.

Curriculum Vitae

Name

Prof. em. Dr. Heinz Hoffmann

Education and Positions

  • University in Würzburg, TH Karlsruhe
  • Diplom in Chemistry 1959
  • Ph. D. at TH Karlsruhe 1962
  • Post-doc and research associate at Case Western Reserve University Cleveland Ohio 1962 - 1968
  • Habilitation at University of Erlangen-Nürnberg 1969
  • full Professor at University Bayreuth 1975 – 2003

Present position

  • 2003, October 1st Prof. em. at Univ. of Bayreuth
  • Member of BZKG
  • Director of BayColl (private research Institute)

Awards

  • "Nernst" award of the "Deutsche Bunsengesellschaft" 1976
  • Wolfgang-Ostwald-Award of the "Kolloidgesellschaft" 1995
  • Lecture-ship Award from the Chemical Society of Japan 1998
  • Lecture-ship Award from the Chemical Society of India, Bombay 1998
  • Overbeek Gold Medal from the European Colloid and Interface Society, Berlin 2011

Honorary Positions

  • 1986 founding chairman of European Colloid and Interface Society (ECIS)
  • 1987 - 2000 General Secretary of ECIS
  • since 2000 honorary-member of ECIS till 2009
  • 1987 - 1991 chairman of Kolloidgesellschaft e. V.

Guest professor ships

  • 1984 - 1985 visiting scientist at the Du Pont Comp. in Wilmington Delaware
  • Oct. and Nov. 1989 visiting Professor at Tokyo Science University
  • 2002 visiting scientist at Cornell University (USA)
  • 2002 visiting scientist at the National Institute of Marine Science (CSMCRI) Bhavnagar (India)
  • 2004 visiting scientist at the Shandong University at Jinan (China) and lecture tour in China
  • 2005 lecture tour in Japan (Yokohama, Tokyo Kyoto, Fukuoka, Nagoya)
  • 2011-2012 visiting guest professor at King Saud University Riad (Saudi Arabia)


Major research area

Systems and phenomena in Colloid Science: micellar structures and lyotropic l. c. phases, vesicles, watersoluble polymers and surfactants, viscoelastic solutions, silica gels, microemulsions, kinetics of micelle formations, phase transitions, fracture fluids, drag reduction, clays, blockcopolymers, proteins

Experimental methods

Rheometry, flow and electric birefringence, polarization microscopy, surface a. interfacial tension, Cryo- and FF-TEM, SANS.

Publications

more than 350 publications

Initiator of

  • ECIS (European Colloid and Interface Society)
  • BZKG: Bayreuther Center of Colloid and Interface Science
  • BayColl



                        


Publications

  1. Interaction between a cationic fluorocarbon surfactant with bovine serum albumin: ultraviolet-circular dichroism and 19FNMR study
    Shuli Dong, Guiying Xu, H. Hoffmann
    Submitted
  2. Phase transition of precipitation cream with densely packed multilamellar vesicles by the replacement of solvent
    Yuwen Shen, H. Hoffmann and Jingcheng Hao
    Langmuir 2009, 25 (18) 10540
  3. Microemulsions from silicon-oil with an anionic/nonionic surfactant mixture
    Lukas Wolf, Heinz Hoffmann, Kei Watanabe, Tohrun Okamoto
    Phys. Chem. Chem. Phys. 2011, 13, 3248
  4. Solubilization of a functionalized silicon oil in a surfactant solution
    Dieter Gräbner, Li Xin, H. Hoffmann, O. Schneider
    Journal of Colloid and Interface Sci. 350 (2010), 516-522
  5. Preparation and characterization of a calcium carbonate aerogel
    Johann Plank, Heinz Hoffmann, Joachim Schölkopf, Wolfgang Seidl, Ingo Zeitler, Zheng Zhang
    Research Letters in Material Sci. Vol. 2009, Article ID 138476
  6. Influence of co-solvent on the rheological behavior of aqueous viscoelastic surfactant systems
    H. Hoffmann, and R. Abdel-Rahem
    Colloid Polym. Sci. (2010) 288:603-612
  7. Aggregation behavior of fluoro- and hydrocarbon cationic surfactant mixtures: A study of 1HNMR and 19FNMR
    Shuli Dong, Guiying Xu, Heinz Hoffmann
    Submitted
  8. Phase and self-assembly transition induced by glycerol-borax interaction in aqueous surfactant two-phase system
    Ying Zhao, Yun Yan, Lingxiang Jiang, Jianbin Huang and H. Hoffmann
    Soft matter 2009, 5, 4250-4255
  9. Influence on the La-phases of siloxane surfactant swollen by glycerole
    Yun Yan, Ying Zhao, Jianbin Huang, H. Hoffmann
  10. Cryo-TEM imaging of a novel microemulsion system of silicone oil with an anionic/nonionic surfactant mixture
    Wolf L., Hoffmann H. Talmon, Y., T. Teshigawara, K. Watanabe,
    Soft Matter 2010, 6, 5367
  11. Microemulsions from silicone oil with an anionic7nonionic surfactant mixture
    Lukas Wolf, Heinz Hoffmann, Kei Watanabe and Tohru Okamoto
    Phys. Chem. Chem. Phys., 2011, 13, 3248-3256
  12. Dynamic properties of microemulsions in the single-phase channels
    Lukas Wolf, Heinz Hoffmann, Walter Richter, Takashi Teshigawara, and Tohru Okamoto
    J. Phys. Chem. B 2011, 115, 11081-11091
  13. Microemulsions with a HIPME (High Internal Phase Microemulsion) structure
    L. Wolf, H. Hoffmann, Takashi Teshigawara, Tohru Okamoto, and Yeshayahu Talmon
    J. Phys. Chem. B, 2012, 116 (7), pp 2131-2137
  14. PFG-NMR self diffusion measurements in the single phase channels of a microemulsion system with an anionic/nonionic surfactant mixture
    Lukas Wolf, Heinz Hoffmann, Jürgen Linders, Christian Mayer
    Soft Matter 2012, 8, 2731-2739
  15. Unique emulsions based on biotechnically produced hydrophobins
    M. Reger, T. Sekine, T. Okamoto and H. Hoffmann
    Soft Matter 2011, 7, 8248-8257
  16. Pickering emulsions stabilized by novel clay-hydrophobin synergism
    M. Reger, T. Sekine, Tohru Okamoto, K. Watanabe, H. Hoffmann
    Soft Matter 2011, 7, 1102111030
  17. Hydrophobin coated boehmite nanoparticles stabilizing oil in water emulsions
    Martin Reger, Heinz Hoffmann
    Journal of Colloids and Interface Science 2012, febr. 15, 368 (1), 378-86, Epub 2011 Nov. 9
  18. Boosting the stability of protein emulsions by the synergistic use of proteins and clays
    Martin Reger, tomoko Sekine, Heinz Hoffmann
    Colloid Polym. Sci. (2012), 290 (7) 631-640
  19. Pickering emulsions stabilized by amphiphile covered clays
    Martin Reger, Tomoko Sekine and Heinz Hoffmann
    Colloids & Surfaces A: Physicochem. & Eng. Aspects, Vol. 413, 5 November 2012, p. 25 -32
  20. Hydrogels from Diacylphosphatidylocholin
    K. Shinto, H. Hoffmann, K. Watanabe, T. Teshigawara
    Coll. Polym Sci. Vol. 290, 1 (2012), 91-95
  21. Structure formation in surfactant solutions A personal view of 35 years of research in surfactant science.
    Heinz Hoffmann
    Advances in Colloid and Interface Sci. 2012, 178, 21-33 (doi:10.1016/j.cis.2012.06.001)
  22. Pulse-field gradient NMR measurements on hydrogels from phosphocholine
    Jürgen Linders, Christian Mayer, Tomoko Sekine, and Heinz Hoffmann
    J. Phys. Chem. B 2012, 116, 11459-11465 ( dx.doi.org/10.1021/jp3046565)
  23. Bilayer swelling of nonionic surfactant and sodium dodecylsulfate mixed system by refractive-index matching
    Yuwen Shen, Heinz Hoffmann, Lihua Jiang, Jingcheng Hao, Zhaohui Liu
    Colloid Polym. Sci. (2012) 290: 1493-1499 (DOI 10.1007/s00396-012-2665-3)
  24. Emulsions with unique properties from proteins as emulsifiers
    H. Hoffmann, M. Reger
    Advances in Colloids and Interface Science (2014), 205, 94 - 104
  25. Hydrogels from phospholipid vesicles
    D. Gräbner, H. Hoffmann, S. Förster, S. Rosenfeldt, J. Linders, C. Mayer, Y. Talmon, J. Schmidt
    Advances in Colloid and Interface Science,  2014, http://dx.doi.org/10.1016/j.cis.2014.02.011