Block copolymers experimental protocol

NMR has not been widely employed to study dynamics in block copolymer melts, although field gradient NMR can provide a wealth of information on the diffusion of block copolymer chains (Fleischer et al. 1993). The orientation of a deuterated homopolymer in a lamellar diblock copolymer (in a glassy state) was determined using 2H NMR by Valic et al. (1994,1995). Other applications of NMR to probe polymer chain dynamics and details of experimental protocols are described by Bovey and Jelinksi (1989). 

Mucosal and systemic antibody responses were measured following oral (OR) and SQ immunization by a nanoparticulate-formulated protein. For oral immunizations, C57BL/6 female mice, 6-8 weeks old, were used in groups of 10 animals. Animals were immunized by gavage using a dose volume of 500 pL. Experimental formulations were prepared so each dose contained a certain load of protein (Table 4). Formulations tested included soluble protein, protein in the nanoparticulate form, protein mixed with empty nanoparticles and protein formulated with CRL-1005 non-ionic block copolymer. The immunization protocol included two immunizations one month apart. Blood, feces and saliva were collected from immunized mice on study days 21,28,49 and 56 and stored at -70 °C until tested. 

Block copolymer self-assembly provides an elegant, cheap, and environmentally sustainable way to produce mesoporous templates. After adoption of an appropriate nanomorphology during phase separation the selective removal of one block yields the desired mesoporous template. In the past few years, a number of experimental protocols on the selective degradation of one copolymer component have been reported, see Table 1.1. Of particular interest are systems containing poly(styrene), since it is cheap, cross-linkable, chemically resistant against most bases and acids. 

Figure 9.32b gives, for comparison, log G versus log G" plots for a low-density polyethylene (LDPE) specimen subjected to the thermal history as described in the temperature protocol given in Figure 9.32a. It is clearly seen in Figure 9.32 that the log G versus log G" plot shows temperature independence, regardless of the thermal history to which the specimen was subjected. Such an experimental observation is expected because LDPE is a flexible homopolymer. The point we try to make here is that for a TLCP with textures, its morphology changes with temperature. In the preceding chapter we made similar observations in microphase-separated block copolymers.

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