SEGMENTED POLY(TETRAMETHYLENE OXIDE) ZWITTERIONOMERS AND THEIR HOMOLOGOUS IONENES .1. SYNTHESIS, MOLECULAR CHARACTERIZATION, AND THERMAL-STABILITY

The synthesis of segmented poly(tetramethylene oxide) (PTMO) zwitterio nomers and their homologous ionenes was achieved through a multistep s trategy involving (i) polyaddition of living bifunctional monodisperse PTMO chains (THF/(CF3SO2)(2)O/20 degrees C, M(n)(o) similar to (2-7) x 10(3)) over diamines (CH3)(2)N(CH2)(X)N(CH3)(2) (x = 2, 3, 6) or alp ha,omega-dimethylamino-PTMO to yield segmented PTMO ionenes with fairl y high degrees of chain extension (N-w(i) similar to 20-170), (ii) qua ntitative exchange of the triflate anion on the ionene by propanesulfo nate (CH3(CH2)(2)SO3-) and ethoxydicyanoethenolate (C2H5OCOC-(CN)(2)) anions, (iii) quasi-quantitative and selective demethylation of the or iginal ionene (LiEt(3)BH in THF at 50 degrees C, demethylation selecti vity s = 0.97 +/- 0.01) to yield tertiary amino segmented PTMO with on ly weak chain degradation, and (iv) quantitative functionalization of the tertiary amino polymeric precursor into the zwitterionomers of the ammonioalkanesulfonate (N+(CH2)(p)SO3-, p = 3, 4) or (ammonioalkoxy)d icyano-ethenolate (N+(CH2)(p)OCOC-(CN)(2), p = 2, 3) type. For all the functionalized polymers, weight loss under nitrogen does not occur be low 200 degrees C, and the thermal stability of the zwitterionic struc ture at 130 degrees C over long periods (24 h) is well ascertained. Be cause of the good control of their structural parameters; these tailor -made segmented PTMO should allow a comprehensive analysis of the typi cal microphase separation of the hard dipolar units within the soft PT MO matrix as a function of their structure (dipole moment, bulkiness, comparison between zwitterions and ion pairs) and of their density alo ng the chain.