Anthracene-labeled polystyrene/poly vinyl methyl

Phase separation of polystyrene/poly(vinyl methyl ether) blends was induced under spatially and temporally periodic forcing conditions by taking advantage of either photodimerization of anthracene or photoisomerization of /rt//i .9 stilbene chemically labeled on polystyrene chains. Significant mode election processes driven by these reactions were experimentally observed and analyzed for both cases. These experimental results reveal a potential method of morphology control using periodic forcing conditions. 

Samples used in this work are the binary polymer mixtures with the characteristics illustrated in Table 10.1. Here, PSA and PSAF stand, respectively, for polystyrene labeled with anthracene and polystyrene doubly labeled with anthracene and fluorescein used as a fluorescent marker. On the other hand, PSC and PVME stands respectively for polystyrene labeled with trans-cirmamic acid and poly(vinyl methyl ether). The factor a in Table 10.1 indicates the label content of anthracene in the polystyrene chain in the unit of number of labels per one chain. For PSC, the label content is 1 cinnamic acid per 28 styrene monomers. 

Samples used in this work are the mixtures of poly (vinyl methyl ether) (PVME, 1.0 X 105, M = 2.5) and polystyrene (PS) derivatives. To be able to induce phase separation by light, the PS component was chemically labeled with photoreactive groups, either with anthracene (A) or rra/i -stilbene (S). The synthesis procedure of these polymers was published elsewhere (8,16). 

Experiments on temporally forcing of phase separation were performed using mixtures of poly(vinyl methyl ether) (PVME) and anthracene-labeled polystyrene (PSA). The phase diagram of this PSA/PVME blend is illustrated in Figure 1 together with the composition dependence of its glass transition... 

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