3D structure of dendritic and hyper-branched macromolecules by X-ray diffraction

نویسندگان

  • Valeri Petkov
  • Vencislav Parvanov
  • Donald Tomalia
  • Douglas Swanson
  • Debora Bergstrom
  • Tom Vogt
چکیده

The atomic ordering in dendritic and hyper-branched macromolecules has been determined by X-ray diffraction. The approach of the atomic pair distribution function technique has been used due to the lack of 3D periodicity in these polymeric materials. Dendrimers are found to possess a semi-regular structure riddled with nanosize cavities. The cavities are joined into channels connecting dendrimer’s surface and core. In contrast, hyper-branched polymers are rather irregular at the atomic scale and with less accessible interior. q 2005 Elsevier Ltd. All rights reserved. PACS: 61.10.Nz; 61.41.Ce; 61.43.Bn

برای دانلود رایگان متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

منابع مشابه

Normal Heptane Reforming of Promoted Platinum Composite Catalysts: Preparation, Characterization and Catalytic Performance

Pt/Zr(x)-HMS/HZSM-5 catalysts with different ratios of Silicium/Zirconium (denoted as x) were studied for normal heptane reforming at 350-450 °C temperature range. For this purpose, the properties of the catalysts such as X-ray diffraction, X-ray fluorescence, Fourier-transform infrared spectroscopy, Ultraviolet–visible diffuse reflectance spectroscopy, NH3-temperature pro...

متن کامل

Surface Hardness Measurment and Microstructural Characterisation of Steel by X-Ray Diffraction Profile Analysis

An X-ray diffraction line will broaden considerably when steels change into martensitic structure on quenching. The results presented in this paper show that X-ray diffraction technique can be employed for a rapid and nondestructive measurement of hardness of hardened steel. Measurement on various quenched and tempered steels showed that the breadth of its diffraction peak increased with increa...

متن کامل

Nano-structural Characterization of Post-annealed ZnO Thin Films by X-ray Diffraction and Field Emission Scanning Electron Microscopy

ZnO thin films were deposited on Si(400) substrates by e-beam evaporation technique, and then post-annealed at different annealing temperatures (200-800°C). Dependence of the crystallographic structure, nano-strain, chemical composition and surface physical Morphology of these layers on annealing temperature were studied. The crystallographic structure of films was studied using X-Ray Diffracti...

متن کامل

Nano-structural Characterization of Post-annealed ZnO Thin Films by X-ray Diffraction and Field Emission Scanning Electron Microscopy

ZnO thin films were deposited on Si(400) substrates by e-beam evaporation technique, and then post-annealed at different annealing temperatures (200-800°C). Dependence of the crystallographic structure, nano-strain, chemical composition and surface physical Morphology of these layers on annealing temperature were studied. The crystallographic structure of films was studied using X-Ray Diffracti...

متن کامل

EVALUATION OFDISLOCATION STRUCTURE AND CRYSTALLITE SIZE IN WORN AL-SI ALLOY BY X-RAY DIFFRACTION

Abstract: powerful method for the characterization of microstructures of crystalline materials in terms of crystallite size anddislocation structures. In this paper the effect of the sliding on the microstructure of A356 in the as-cast and heattreated conditions are studied, The X-ray phase analysis shows that with increasing applied load, the dislocationdensity is increased, whereas the crysta...

متن کامل

ذخیره در منابع من


  با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید

عنوان ژورنال:

دوره   شماره 

صفحات  -

تاریخ انتشار 2005