Oscillatory shear alignment

Fig. 25. Preliminary SANS measurements on post large amplitude oscillatory shear confirm the presence of global alignment of the silicate layers.

Once the cross-linking temperature has been attained, add the second KBr disc to the top of the sample and apply pressure to define the sample thickness. If an aligned sample is desired a small, linear, oscillatory shear may be applied at this point (amplitude 5 mm, frequency 1 Hz). 

Shear flow fields are a remarkably effective means of orienting copol5mier microdomains. Large amplitude oscillatory shear (LAOS) and extrusion are common methods used to align... 

Figure 5. The change in G with time during the alignment by an oscillatory shearing with 1 and a = 0.1 rad/s for the as-cast sample of Vector 4111 and yg = 1 and a> = 1 rad/s for the as-cast sample ofSI-Cl. The annealing temperatures for Vector 4111 andSI-Cl were 17ff>C andl60PC, respectively, which corresponded to the HEX microdomains in both block copolymers.

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