Combining X-ray scattering with dielectric and calorimetric experiments for monitoring polymer crystallization Andreas Wurm * , Alexander A. Minakov, Christoph Schick University of Rostock, Inst. of Physics, Universitätsplatz 3, 18051 Rostock, Germany article info Article history: Received 13 November 2008 Received in revised form 7 July 2009 Accepted 21 July 2009 Available online 27 July 2009 Keywords: Polymer crystallization Polycaprolactone X-ray Dielectric Calorimetry Simultaneous measurements abstract In order to understand nucleation; crystallization and other phase transitions in polymers, polymer based composites, or in liquid crystals simultaneous experiments with a combina- tion of different methods are useful. Due to different sample geometry, contact faces with the sample holder, and thermal conditions it is usually difficult to compare the results of several individual experiments. As an important supplement to the classical techniques for studying crystallization like X-ray scattering, or differential scanning calorimetry, mea- surements which test molecular mobility like dielectric or mechanical spectroscopy are of interest during isothermal and non-isothermal crystallization. From such simultaneous experiments one can learn about the existence of pre-ordered structures before formation of crystals, as detected by DSC or X-ray scattering. In this contribution we present the development of a device for simultaneous measure- ments of electrical properties and X-ray scattering intensities, which was extended to a microcalorimeter and allows measuring thermal properties like heat capacity and thermal conductivity additionally at the same time and at the same sample volume. Ó 2009 Elsevier Ltd. All rights reserved. 1. Introduction Starting point of our activities was the intensive discus- sion about the general scheme of the process of polymer crystallization during the last 10 years [1]. Since the begin- ning of the 60 ies the Hoffmann–Lauritzen theory with its several modifications and extensions dominates the discus- sion in the scientific community [2–4]. There was not much space and no urgent need for alternative models because most effects could be described reasonable well. These the- ories assume a transition from the entangled polymer melt to the crystal, having already a final thickness and stability, as a process occurring at the growth front. But there was increasing evidence during the last 10 years, that these the- ories do not describe the process correctly. Especially the observation of ordered structures at very early stages forced the development of new theories and models [5–9]. All these theories assume a multi-step process from the entan- gled melt via different metastable structures to the final polymer crystal. Often only the first or initiating step, as the key step for the whole process, is discussed and de- scribed. This step is assumed to be spinodal decomposition [10–14] or nucleation followed by growth [15–17]. Strobl [18–21] introduced a growth model for polymer crystalliza- tion, which covers the whole process with a few specific steps. These steps are considered to be universal for poly- mer crystallization. The first step is the formation of a meta- stable pre-ordered structure in the super-cooled melt. This structure should be in thermodynamic equilibrium with the surrounding melt and should undergo different annealing stages to a stable lamella step by step. As the last step a stabilization process of the lamellae is assumed. Evidence for that comes from scattering experiments [22–24] and techniques probing properties like shear modulus or melting temperature rather than direct morphological observations [25]. In parallel to the development of new theories and models, specific experiments were performed 0014-3057/$ - see front matter Ó 2009 Elsevier Ltd. All rights reserved. doi:10.1016/j.eurpolymj.2009.07.014 * Corresponding author. Tel.: +49 381 498 6884; fax: +49 381 498 6882. E-mail address: andreas.wurm@uni-rostock.de (A. Wurm). European Polymer Journal 45 (2009) 3282–3291 Contents lists available at ScienceDirect European Polymer Journal journal homepage: www.elsevier.com/locate/europolj