Ultra Strong and Stiff Polymer Matrix Nanocomposites

While nanoscale building blocks are individually exceptionally strong, their properties are difficult to transfer to the macroscale composites made from them. Assembly of a clay (alumniosilicate)/polymer composite one nanoscale layer after another (see figure below) allowed for preparation of a homogeneous material with planar orientation of alumosilicate sheets. Its stiffness and tensile strength are similar to those of steel and are at least an order of magnitude greater than those for similar nanocomposites that do not have the nanoscale precision in particle alignment. These properties are combined with transparency and low temperature processing. Besides

Fig. 1. Preparation of PVS-MTM nanocomposite. (A) Schematic representation of the internal architecture of PVA-MTM composite (picture shows 5.5 bilayers). (B) Atomic force microscopy phase image of a single PVA-MTM bilayer adsorbed on top of a silicon wafer. Top inset gives a simplified schematic representation of the microscopy image. Lower inset is a 1 μm x 1 μm close up of the main image showing individual MTM platelets more clearly. (C) Compilation of UV-V is absorbance spectra collected after multiples of 25 bilayers of PVA-MTM composite deposited on a microscope glass slide. (D) Free-standing, 300-bilayer PVA-MTM composite film showing high flexibility and high transparency. Lower image is taken at an angle to show diffraction colors. (need to explain why transparency is so important here)

obvious technological importance of such composites, the realization of nearly perfect load transfer from individual sheets to the macroscale material is fundamentally important for the design of ultrastrong materials. This collaborative work between the Waas group (Aero) Arruda group (ME) and the Kotov group (Chem. Eng.) is currently investigating fracture properties of the nanolayered films and also the high strain rate mechanical performance for a variety of applications (sponsor: ONR).

Reference:

Podsiadlo P, Kaushik AK, Arruda EM, Anthony M. Waas et al., Ultrastrong and still layered polymer nanocomposites SCIENCE 318 (5847): 80-83 OCT 5, 2007.