Final Report Summary - AMAAOOINCPOS (Architectures, morphologies and applications of organic/inorganic nanomaterials containing polyhedral oligomeric silsesquioxane)
1) Preparation of functionalized polyhedral oligmeric silsesquioxane (POSS):
We have prepared a series of functionalized POSS molecules which can be used as monomers, initiators and “click chemistry” agents. For example, we synthesized the POSS-containing monomer with a long side methylacrylate group (Figure 1), which have been used to POSS-containing with high molecular weight.
2) Preparation of POSS-containing hybrid polymers with different topological structures:
For example, we have synthesized amphiphilic hybrid block copolymers, poly(methacrylisobutyl-POSS)-b-poly(2-((dimethylamino)ethylmethacrylate) (P(MA-POSS)-b-PDAEMA) using ATRP (Figure 2). We first prepared alternating POSS-containing copolymers. POSS-containing poly(tert-butyl acrylate) (Glu-PtBA-POSS5) with a penta-telechelic structure was prepared by the combination of ATRP and “click chemistry”. The penta-telechelic Glu-PtBA-POSS5 was further hydrolyzed into POSS-containing penta-telechelic poly(acrylic acid) (Glu-PAA-POSS5) using trifluoroacetic acid.
3) Self-assembly of POSS-containing hybrid amphiphilic copolymers
In past reports on the self-assembly of POSS-containing hybrid polymers, the self-assembly morphologies were mostly studied in bulk. For example, a lamellar self-assembly nanostructure can be obtained from POSS-containing random or block copolymers. There are few reports on the self-assembly behavior of POSS-containing hybrid polymers in solution. In our present work, we studied a series of POSS-containing amphiphilic copolymers in solution. For example, P(MA-POSS)-b-PMAA block copolymers can self-assemble into string like shapes in aqueous solution (Figure 4a). We also obtained the assembled spherical aggregates from P(MA-POSS)-b-PDAEMA block copolymers in aqueous solution (Figure 4b). Interestingly, the giant assembled capsules were obtained from the self-assembly Glu-PAA-POSS5 in aqueous solution (Figure 5). From its enlarged image, the surface of the Glu-PAA-POSS5 is relatively homogeneous, except for several dark dots. This indicates that POSS does not form some bigger aggregation in the membrane of the capsule. Thus, this is typical capsule obtained from self-assembly of hybrid copolymers, which is a similar to the conventional one prepared by LbL assembly technique.