Architectural copolymers of PAMAM dendrimers and ionic polyacetylenes

Novel, star-shaped copolymers have been prepared to study the resulting pro perties of the core-shell copolymers. While the shell was formed from rigid , conductive ionic polyacetylene (PAc) arms, semiflexible, spheroidal aliph atic poly(amidoamine) (PAMAM) dendrimers served as initiator cores. The syn thesis was carried out;it room temperature by reacting the primary amino te rminal groups of the generation three and four PAMAM dendrimers with N-meth yl-2-ethynylpyridinium triflate in DMSO at different monomer/initiator rati os. Full surface functionalization of the amino groups was achieved at the 2EPyMeTf/PAMAM-NH2 = 4 monomer/terminal amino group ratio when the whole su rface was; found to be completely covered with short rigid ionic acetylene chains giving macromolecular "sea urchins". Depending on the chain length o f the polyacetylene,arms and the degree of dendrimer surface coverage, thes e core-shell polymers may be considered as functionalized dendrimers or den drimer-initiated ionic polyacetylenes. The resulting products were characte rized by FTIR, W-visible, H-1 and C-13 NMR spectroscopy, capillary electrop horesis, TEM, TGA, DSC, and conductivity measurements. Solid-state conducti vity of the doped copolymer was found to be in the 10(-4)-10(-5) S/cm range due to the shorter conjugation length in the ionic polyacetylene shell. Ho wever thermal stability of the PAMAM dendrimer interior improved dramatical ly as a result of copolymer formation.