Project 2

Scientific highlights (general progress of this project, most important scientific achievement made)
A new method was developed for online heat capacity measurements during temperature scan of materials within wide range of controlled scanning rates, witch were never covered before. Combination of conventional DSC technique, single sensor ultra-fast and differential fast scanning techniques covers now a temperature scanning rate range from 0.001 K/s to 10⁶ K/s.
These three techniques were used for investigation of solidification kinetics of metal microparticles and study of reorganization processes in polypropylene with different additives (nucleating agents).
A large number of experiments were performed on Sn and alloy particles (Dr. Y.L. Gao, Shanghai University) of size from 10 nm to 500 µm. It was shown, that particles do not reveal expected shift of crystallization temperature with increasing cooling rate and reducing particle size. In the range from 10^-2…10⁵ K/s crystallization temperature changes step-like and description needs a better understanding of the nucleation mechanisms in the sample.
First experiments on the formation of quasi crystals were conducted together with Carmen Mihoc, another Marie Curie EST fellow from ADVATEC project. With introduction of the new high temperature sensor end of 2008 these experiments will be continued.
The new technique was also used to study the influence of different nucleating agents on melting and crystallization kinetics of isotactic polypropylene (iPP) (Marilena Pezzuto, ICTP, Pozzuoli, Italy, H. Kothe, DKI Darmstadt). The change from heterogeneous to homogeneous nucleation is seen in the figure below.

One of two measureing cells of Differential Fast Scanning Calorimeter
- allows ultra-fast controlled heating and cooling of nanogram samples

Fellow	Dipl.-Phys. Evgeny Zhuravlev
Foreseen duration	36 months
Start Date	15.09.2006
End Date	15.09.2009
Ministering Institut	University of Rostock, Institute of Physics, Polymer Physics (Prof. Schick)
Project Images	Temperature profile of calorimetric experiment with polypropylene.     The heat capacity of polypropylene with different fillers during experiment described above. Phase transition kinetics was studied in range of scanning rates 10…105­ K/s     The time needed for crystallization of polypropylene at different temperatures.
Project Goal	Recently developed calorimetric techniques based on submicron membranes allow the investigation of kinetic and thermodynamic features of structure formation in thin films or in very small (below µg) samples. The short response time of the calorimeter allows the formation of far from equilibrium structures with quenching rates of the order of µsec/K, a performance at present unique in Europe to our best knowledge. Crystallization processes may also be followed at millisecond time scale. Since most nanomaterials are in far from equilibrium thermodynamic states due to their synthesis conditions, this new technique allows to study complex nanostructure formation under processing relevant conditions. E.g. heating rates applied during ultrafast conventional or microwave heating can be mimicked. The microstructure formation and evolution in ultrathin polymer ceramic and polymer metal films is of particular interest with respect to the end properties of the composite films. Steric effects exerted by the polymer matrix control the size and volume distribution of embedded particles. Very narrow size distributions may be achieved using modified sol gel procedures.
Description	The thickness and cooling rate dependence of the glass transition, melting, crystallization, chemical reactions, etc. will be investigated. New insight in these processes can be revealed from heat of fusion and complex heat capacity of nanometer thick films, which can be measured as function of temperature or time. The experimental timescales are coming close to those available for the computer simulation of polymer crystallization allowing direct interaction of theory and experiment in the field of crystallization in thin polymer films. The work will be performed in close collaboration with the groups at the Institute of Physics. Applications are foreseen in photocatalysis, optical coatings, sensors, etc. The project will be hosted by the Institute of Physics, Polymer Physics Group. A new method was developed for online heat capacity measurements during temperature scan of materials within wide range of controlled scanning rates, witch were never covered before. Combination of conventional DSC technique, single sensor ultra-fast and differential fast scanning techniques covers now a temperature scanning rate range from 0.001 K/s to 106 K/s. These three techniques were used for investigation of solidification kinetics of metal microparticles and study of reorganization processes in polypropylene with different additives (nucleating agents). A large number of experiments were performed on Sn and alloy particles (Dr. Y.L. Gao, Shanghai University) of size from 10 nm to 500 µm. It was shown, that particles do not reveal expected shift of crystallization temperature with increasing cooling rate and reducing particle size. In the range from 10-2…105 K/s crystallization temperature changes step-like and description needs a better understanding of the nucleation mechanisms in the sample. First experiments on the formation of quasi crystals were conducted together with Carmen Mihoc, another Marie Curie EST fellow from ADVATEC project. With introduction of the new high temperature sensor end of 2008 these experiments will be continued. The new technique was also used to study the influence of different nucleating agents on melting and crystallization kinetics of isotactic polypropylene (iPP) (Marilena Pezzuto, ICTP, Pozzuoli, Italy, H. Kothe, DKI Darmstadt).
Papers in international peer reviewed conferences,	“Calorimetric measurements of undercooling in single micron sized SnAgCu particles in a wide range of cooling rates”, Y.L. Gao, E. Zhuravlev, C.D. Zou, B. Yang, Q.J. Zhai, C. Schick , Thermochimica Acta, in press.   Several posters on Differential Fast Scanning Calorimetry technique and its application for study of melting and solidification kinetics of metals and polymers were presented on following meetings: 72 Annual Meeting of the DPG, 25-29 February 2008, Berlin, Germany 10th Lähnwitzseminar on Calorimetry, 8-13 June 2008, Rostock, Germany The Polymer Processing Society 24th Annual Meeting, 15-19 June 2008, Salerno, Italy Marie Curie Conference, 17-18 July 2008, Barcelona, Spain NATAS 36th Annual Conference, 16-20 August 2008, Atlanta GA, USA The 13th International Conference on Rapidly Quenched & Metastable Materials RQ13 24-29 August 2008, Dresden, Germany
Talks on Conferences, Participation in workshops, summer schools, study visits and tutorials,   Reports	Two talks on the new calorimetric technique and its application for study of polymers and metallic particles solidification were given on NATAS 36th meeting and RQ13 conference in Dresden.   On the 36th NATAS conference a Graduate Student Travel Award was received for the lecture “Differential Fast Scanning Calorimeter”.   Seminars: ADVATEC annual report Polymer Physics Laboratory Group Meeting DoktorandenSeminar SS08 Talk topic: “Solidification of Polymers and Metal Nano-Particles. Differential Fast Scanning Calorimetry Technique”
Publications	“Calorimetric measurements of undercooling in single micron sized SnAgCu particles in a wide range of cooling rates”, Y.L. Gao, E. Zhuravlev, C.D. Zou, B. Yang, Q.J. Zhai, C. Schick , Thermochimica Acta, in press (11.12.2008).
Partners	H. Kothe, DKI Darmstadt, Germany Marilena Pezzuto, ICTP, Pozzuoli, Italy Y.L. Gao, Shanghai University, China Dongshan Zhou, Nanjing University, China Gerrit Günther, TU Darmstadt, Germany Dear colleagues, sorry if I don’t mention someone – the list should be much larger and will be updated. I just write in what was in opened documents during first filling of the page.
Using Devics and Instruments	IR spectrometer, GC – Mass spectroscope, SAXS, WAXS, AFM, TEMs, SEMs, Differential scanning calorimeter (DSC), etc.