Poly(4-vinylpyridine) (P4VPy) was blended with the lithium or zinc salt of poly(styrenesulfonate) (PSSLi and PSSZn, respectively). P4VPy formed complexes with PSSZn but not with PSSLi in water/ethanol (2:1) solutions, indicating the presence of a strong interaction between PSSZn and P4VPy. P4VPy is immiscible with PSSLi, as shown by the appearance of two glass transitions in each P4VPy/PSSLi blend. Fourier transform infrared spectroscopic measurements showed the development of a new pyridine ring mode in P4VPy/PSSZn complexes. X-ray photoelectron spectroscopic (XPS) studies showed the development of high-binding-energy (BE) N 1s peaks in all the P4VPy/PSSZn complexes but not in the P4VPy/PSSLi blends. Interaction between P4VPy and Zn2+ is also evidenced by the development of a low-BE S 2p doublet in each complex. Therefore, XPS reveals the existence of coordination between Zn2+ and P4VPy but not between Li+ and P4VPy.

A low-molecular-weight poly(N-acryloyl-N‘-methylpiperazine) (PAMP-L) forms miscible blends with poly(p-vinylphenol) (PVPh) while a high-molecular-weight PAMP-H forms complexes with PVPh in ethanol solutions. The glass-transition temperatures of all the blends and complexes are higher than those predicted by a linear additivity rule. The specific interactions between PAMP and PVPh were studied by Fourier transform infrared (FTIR) spectroscopy and X-ray photoelectron spectroscopy (XPS). FTIR shows that the hydroxyl group of PVPh interacts with both the carbonyl oxygen and the amide nitrogen of PAMP as shown by the development of a low-frequency and high-frequency carbonyl band in each blend and complex. The amide nitrogen and amine nitrogen of PAMP are discernible by XPS. Both types of nitrogens are involved in interactions with PVPh as shown by the development of two additional high-binding-energy N 1s peaks in each blend or complex. All three types of interacting sites of PAMP interact with the hydroxyl groups of PVPh.

Polymer complexes of a basic polymer, poly(N-methyl-4-piperidinyl methacrylate) (PMPMA), with a weak acidic polymer poly(p-vinylphenol) (PVPh), and strong acidic polymers such as poly(acrylic acid) (PAA), poly(methacrylic acid) (PMAA), poly(styrenesulfonic acid) (PSSA), and poly(vinylphosphonic acid) (PVPA), have been prepared by mixing ethanol/H2O (1:1) solutions of the respective components. The complexes were examined by Fourier transform infrared (FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS), and differential scanning calorimetry. Both the FTIR and XPS studies showed the existence of piperidinium ions in the complexes of PMPMA with PAA, PMAA, PVPA, and PSSA, indicating that the interactions in these complexes are ionic in nature. However, the N-methyl groups prevent the piperidine nitrogen atoms from interaction with PVPh and hence the carbonyl groups of PMPMA interact with the hydroxyl groups of PVPh by hydrogen bonding. From the XPS studies, the number of protonated piperidine atoms was found to correlate with the acid strength of the polyacid.

Poly(N-acryloyl-N ‘-phenylpiperazine) (PAPP) forms miscible blends with poly(p-vinylphenol) (PVPh), and it forms complexes with three stronger acidic polymers, namely, poly(styrenesulfonic acid) (PSSA), poly(vinylphosphonic acid) (PVPA), and poly(acrylic acid) (PAA). Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy were used to study the nature of interpolymer interactions in these blends and complexes. All three types of interacting sites of PAPP are involved in interactions with the acidic polymers. PAPP interacts with PVPh and PAA through hydrogen-bonding interaction, whereas it interacts with PSSA and PVPA through a combination of hydrogen-bonding and ionic interactions. As compared to poly(N-acryloyl-N ‘-methylpiperazine), the interactions between PAPP and the acidic polymers are less intense because of the steric shielding effect of the phenyl groups and the lower basicity of the tertiary amine nitrogen.

SUMMARY: C 60 undergoes nucleophilic addition with 2-(2-aminoethyl)pyridine in chlorobenzene to produce multifunctional 2-(2-pyridyl)ethylaminofullerene (PYEAF) with an average stoichiometry of [C 60 H 8 (NHCH 2 -CH 2 C 5 H 4 N) 8 ]. PYEAF was mixed with poly(styrenesulfonic acid) (PSSA), poly(vinylphosphonic acid) (PVPA), poly(acrylic acid) or poly(methacrylic acid) in THF/methanol (1/2 v/v) to form fullerene-containing polymer complexes. All complexes do not show distinct glass transitions up to the degradation temperatures. The interactions between PYEAF and the polymers were studied by means of X-ray photoelectron spectroscopy. Protonation of nitrogen in PYEAF was shown by the development of a high-binding energy N1s peak in all complexes. The fraction of protonated nitrogen in the complex depends on the acidic strength and the amount of the polymer. The S2p spectra of PYEAF/PSSA complexes and the P2p spectra of PYEAF/PVPA complexes further show the existence of sulfonate ions and phosphonate ions, respectively. The strong ionic interactions between PYEAF and all these acidic polymers lead to the formation of complexes.