2006 Volume 75 Issue 4 Pages 461-466
The true mechanism of the onset of crystallization is still unclear. Classical nucleation theory (CNT) assumes the concept of “nucleation” in the 1930s1. It has thus far been impossible to observe directly nano nucleation due to technical difficulties. Here, we show the direct observation of nano nucleation for the first time by overcoming the above difficulties. The real image of nucleation will enable us to control the ultimate structure and physical properties of materials. We discovered a novel morphology of a “spiral” crystal which is named “spiralite”, in the crystallization of polymers under shear flow. The spiralite rotates, showing high and low growth rates (Vspiral(max) and Vspiral(min)). They are seen along directions perpendicular (Z-axis) and parallel (X-axis) to the flow direction, respectively. It is concluded from a kinetic analysis of accerelation of the growth rate, that Vspiral(max) is an evidence of the formation of the oriented melt on the surface of the spiralite along the Z-axis, due to the significant increase in shear rate γ ⋅ (Z) at the interface.
