Polymers complex formation

We also found the saturation kinetics for alkaline hydrolyses of 44 (PNPA), 3-nitro-4-acetoxybenzoic acid 56 (NABA), and 3-nitro-4-acetoxybenzenearsonie acid 57 (NABAA) in the presence of QPVP1025. If ester-polymer complex formation occurs prior to the attack of OH-, Eq. (5) holds, according to Bunton etal. 103 where K is the equilibrium association constant of polyelectrolyte (PE) and ester (S), and kt the first-order rate coefficients1035, PE, S, and P indicate the poly-... 

The synergism of surfactant-polymer complex formation has been studied by gel permeation chromatography [114],... 

Fig. 9. Polymer complex formation between PAAc and PAAm by hydrogen bonding at low temperature...

Mi, K. Y., Yong, K. S., Young, M. L., and Chong, S. C. Effect of polymer complex formation on the cloud-point of poly(Al-isopropylacrylamide) (PNIPAAm) in the poly(NIPAAm-co-acrylic acid) polyelectrolyte complex between poly(acrylic acid) and poly(l-lysine). Polymer 39 3703-3708, 1998. 

The use of fluorescence techniques for the characterization of the behavior of chain molecules in solution offers a number of important advantages (a) Since fluorescence can be detected at extreme dilution of the emitting species, labeling polymers with fluorophores need not result in significant modifications of their other properties. (b) Since the lifetime of the excited chromophore, I, Is generally of the order of 10 ns, the kinetics of fast processes whose relaxation times are comparable to t may be studied by fluorescence techniques. nonradiative energy transfer over relatively long distances may be used to characterize the spatial relation of donor and acceptor labeled chain molecules, (d) The medium sensitivity of the emission from the "dansyl" label has been used to study polymer complex formation and the transition of chain molecules from a contracted to an expanded state. 

YOO Yoo, M.K., Sung, Y.K., Cho, C.S., and Lee, Y.M., Effect of polymer complex formation on the eloud-point of poly(iV-isopropylaciylamide) (PNIPAAm) in the poly(NIPAAm-co-aeiylic add) Polyelectrolyte complex between poly(aciylic acid)... 

In attempts to reconstitute nucleosomes on SV40 circular DNA, Cap-lan et al. (37) observed that if the histones were ADP-rihosylated prior to reconstitution assembly of nucleosomes was inhibited by as much as 80%. If nucleosomes were first allowed to assemble, then modified by ADP-ribosylation, no eflPect on stability was observed. These data led the authors to speculate that ADP-ribosylation of histones prior to nucleosome assembly might be of physiological importance. Perella and Lea (168, 169) have shown that in rat liver nuclei, polyamines cause an increase in histone Hi ADP-ribosylation and histone HI dimer synthesis, which is accompanied by a decrease in core histone ADP-ribosylation. Data such as these have led to speculation that Hi dimer formation may function in the condensation or stabilization of chromatin fibers (35, 119). The data of Lorimer et al. (124) indicate that dimer synthesis is inversely related to the nuclear activity of the poly(ADP-ribose) glycohydrolase. Thus, these authors (124) inferred that the Hl-Hl-polymer complex formation is of a transient nature. As pointed out by Purnell et al. (171), if this crosslink were to function in the stabilization of chromatin, the modified histone Hi would have... 

The product of this elementary step of the surfactant-polymer complex formation, SA. is called a "subaggregate" as distinguished from the entire polymer-surfactant complex molecule which may contain many subaggregates. 

The solution of polymer was titrated with 0.2 M SDS. The endothermic peaks observed when SDS is added to PEG-20 and PEG-30 solutions are more pronounced as compared with the peak observed for pure SDS solution. The pronounced endothermic peaks are due to surfactant-polymer complex formation. The titration curves are parallel for SDS concentrations lower than 5.9 mM. 

The time dependency in Figure 1 suggests that the self-association of the nucleic acid bases in the poly(ethyleneimine) derivatives dissociated slowly by accompanying change in conformation, and formed the intermole-cular polymer complex by the interaction between adenine and thymine bases. Similar results were reported on the polymer complex formation between poly(methacrylate) derivatives of uracil and adenine, where the self association of the uracil bases in the polymer inhibited the polymer complex formation.22 23,26 Therefore, the conformational change of the synthetic polymers seems to be important for the formation of a stable polymer complex. 

Studies of polymer complex formation. Equilibrium characteristics. 

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