PPL – Fisica dei Polimeri e Chimica Macromolecolare
Prof. Claudio De Rosa
Room 2P50; phone +39-081-674346/5 Email claudio.derosa@unina.it;
Prof. Giovanni Talarico
Room 2P-06; phone +39-081-674442/1 Email giovanni.talarico@unina.it;
Dr Rocco Di Girolamo
Room 2P-53; phone +39-081-674307 Email rocco.digirolamo@unina.it;
Dr Anna Malafronte
Room 2P-41; phone +39-081-674309 Email anna.malafronte@unina.it;
Dr Miriam Scoti
Room 2P-41; phone +39-081-674309 Email miriam.scoti@unina.it;
The Polymer Physics Group carries out research in various field of polymer chemistry including the synthesis and the characterization of the structure and of the physical and mechanical properties of polymeric materials, in particular of polyolefins and copolymers of olefins, and of polymer composites. The Group has expertise in the synthesis of stereoregular polyolefins by Ziegler-Natta and organometallic catalysts and in the study of the structure of crystalline polymers. Structural studies are conducted at the highest levels of specialization using all the techniques of characterization of the solid state of materials, from wide and small angle X-ray diffraction, to electron microscopy, to solid state nuclear magnetic resonance. The dominant motive of the research activities is the study of the relationships between the molecular structure, the crystalline structure and the physical properties of crystalline polymers. In particular, these researches have concerned the study of the crystalline structures and physical and mechanical properties of new stereoregular polymers and copolymers prepared with novel organometallic catalysts. The development of homogeneous organometallic catalysts for the polymerization of olefins has allowed the preparation of many new polymers in the last twenty years, some of which have also proved to be of great industrial interest. The properties of these materials have been interpreted on the basis of structural studies and possible practical applications have been identified. These studies have reaffirmed the long tradition of the Italian school in the field of the structural study of polyolefins. Relevant aspect of these structural studies has been the analysis of the structural disorder that is often present in the crystalline phases of polymers and of the molecular organization of the mesomorphic modifications of many polymers. The description of the structural disorder has allowed a better interpretation of the mechanical properties of polymers at molecular level. The ultimate goal of these studies is the complete understanding of the relationships between the structure of the catalyst used for the preparation of polymers, the molecular structure of the produced macromolecules (that is, stereoregularity, regioregularity, distribution of defects and molecular masses), the crystalline structure of the polymers and the physical and mechanical properties of the produced materials (Figure 1).
Figure 1
This knowledge allows for the design of materials with targeted physical properties through the "design" of the catalyst. For example, the study of the influence of the presence of microstructural defects on the structure and properties of isotactic and syndiotactic polypropylene and isotactic polybutene have allowed to modulate and control the physical properties of materials through the targeted introduction of steric and constitutional defects, by means of a suitable choice of the metallocene catalyst. One of the results of scientific and industrial importance has been the development of innovative flexible and elastomeric materials based on isotactic polypropylene and its copolymers with controlled stereo-regularity (Figure 2), and of a new class of elastomers of controlled stiffness, defined as "crystalline elastomers" based on syndiotactic polypropylene and its copolymers with other olefins.
Figure 2
Finally, other research activity concerns the study of nanostructures formed by crystallization and phase separation of semicrystalline block copolymers. Of particular importance is the discovery of a new process for the orientation of phase-separated microdomains and of crystals formed by self-assembly and crystallization, obtaining ordered nanostructures useful for applications in nanotechnologies. In this context, a major research topic of this group consists in the preparation and characterization of hybrid organic/inorganic nano-composites using surface functionalized metal nanoclusters dispersed in polymeric matrices consisting of block copolymer nanostructures. These materials can be used in many applications in microelectronics, such as supports for integrated circuits, non-volatile memories, photonic crystals for the confinement of light, sensors etc. These studies have enabled the development of nanotechnologies based on the engineering of thin film surfaces for the fabrication of microelectronic devices and nanosensors.
Figure 3