User:Moira M. Esson/Notebook/CHEM-581/2013/03/01

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Objectives Conduct pressure tests on all hydrogels using an unmodified pipette. Run fluorescence on all samples collected from the pressure tests. Decant the safflower oil from the microsphere samples prepared on 2013/02/22. Pressure tests using an unmodified pipette All pressure tests were conducted following the general protocol described on 2013/02/20. Pressure tests were conducted using an unmodified pipette in order to determine if the very slight amount of sheer pressure caused by an unmodified pipette would cause a detectable amount of dye diffusion. Table 1. Information concerning the pressure testing involving hydrogels with an unmodified pipette. Sample Order PVOH vs. Clay Ratio PVOH Type Clay Selection Amount of Hydrogel Used (g) 1 50:50 130K 110% CEC NaMT w/ DMHXLBR 0.1006 2 50:50 130K 110% CEC NaMT w/ DMHXLBR 0.1022 3 90:10 130K Laponite 0.1031 4 50:50 146K 110% CEC Laponite w/ DMHXLBR 0.1066 5 90:10 130K 110% CEC Laponite w/ DMHXLBR 0.1083 6 90:10 130K 110% CEC NaMT w/ DMHXLBR 0.1003 7 50:50 130K 110% CEC Laponite w/ DMHXLBR 0.1036 8 50:50 146K Laponite 0.1016 9 90:10 130K 110% CEC NaMT w/ DMHXLBR 0.1011 10 90:10 146K 110% CEC NaMT w/ DMHXLBR 0.1020 11 50:50 130K NaMT 0.1024 12 50:50 130K 50% CEC NaMT w/ Bu3HdP+ 0.1015 13 50:50 146K 110% CEC NaMT w/ DMHXLBR 0.0998 14 90:10 130K 50% CEC NaMT w/ Bu3HdP+ 0.1026 Figure 1. Fluorescence of hydrogel samples modified with Lamponite clay using an unmodified pipette for pressure testing Figure 2. Fluorescence of hydrogel samples modified with NaMT clay using an unmodified pipette for pressure testing Figure 3. Fluorescence of all hydrogel samples using and unmodified pipette for pressure testing Notes: The amount of dye, or concentration of dye, that was diffused from the hydrogels using an unmodified pipette was significantly lower than that of a bent pipette. The general trends observed using a bent pipette were also observed with an unmodified pipette.(Unmodified clay had the highest absorbance values. On average, hydrogels with NaMT clays had a higher absorbance than the hydrogels prepared with lamponite clays. Similarly, the higher molecular weight PVA hydrogels exhibited higher absorbance values, indicating these hydrogels are better at exerting/responding to sheer pressure). Similar to the bent pipette, the concentration of Rhodamine 6G in the samples is extremely low in comparison to the 0.25μM Rhodamine 6G control, with the highest absorbance value of 9.204 observed in the 50:50 ratio of PVA MW 130,000:NaMT in comparison to the highest absorbance value of 606.17999 in the Rhodamine 6G 0.25μM. Another procedure that will exert more sheer pressure will be determined. A new method for the preparation of hydrogels will be considered where a single layer of clay will be incorporated into the hydrogel rather than having clay distributed throughout the hydrogel. Microspheres After the three cycle freeze thaw method, the microsphere samples were removed from the freezer. The microsphere samples were allowed to sit outside of the freezer for approximately 1 week. During this time two distinct layers formed, a layer of the aqueous microspheres formed the lower most layer and a top layer of organic safflower oil formed. In order to obtain the microspheres the safflower oil needed to be removed from the vials. General Protocol for decanting the microspheres: All microsphere samples were placed on a flat surface and allowed to settle for approximately 15 minutes. Without touching the vial or moving the vial containing the microspheres(so as not to disturb the fine particles), a glass pipette was used to carefully removed the safflower oil. The safflower oil was placed in an appropriate waste container. Observations Many of the prepared microspheres became a gel rather than retaining their sphereical shape due to the fact a higher ratio of PVA was present in the PVA safflower oil emulsion. In the future, very small amounts of PVA will be placed in the vials. DSC will be run on both the microspheres and the gels.