Fig. 2.

LiNc-BuO:PDMS chips with increasing spin density. Four different formulations of LiNc-BuO:PDMS, viz. C-5, C-10, C-20, and C-40, were fabricated by incorporating 5, 10, 20 and 40 mg of LiNc-BuO, respectively, in the same amount of PDMS (5.5 g). (a) Spin density of the LiNc-BuO:PDMS chip formulations. Spin density was evaluated, using a pre-calibrated standard, at X-band (9.8 GHz). Results (mean ± SD, n=3), normalized by sample weight, show a linear relationship between mass of particulates incorporated and spin density of the four chip formulations. The calculated spin densities per g of chip weight, of the formulations were also consistent with the spin density of unencapsulated LiNc-BuO, per mg of LiNc-BuO, reported previously (Pandian et al. 2003b). (b) X-band EPR images of LiNc-BuO:PDMS chip formulations. Distribution of spins was evaluated using X-band EPR imaging. Samples were imaged under anoxic condition, in a sealed tube. Image intensity correlated directly with the normalized spin density results shown in (a). Images demonstrate high-degree of uniformity in the distribution of LiNc-BuO spins within the PDMS matrix in all four formulations