Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2017-01-12T13:44:03Z No. of bitstreams: 1 PauloReniereSilvaDeSouza_DISSERT.pdf: 18420723 bytes, checksum: 0dee6d1653465093c4081165eec036ad (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2017-01-17T11:30:54Z (GMT) No. of bitstreams: 1 PauloReniereSilvaDeSouza_DISSERT.pdf: 18420723 bytes, checksum: 0dee6d1653465093c4081165eec036ad (MD5) / Made available in DSpace on 2017-01-17T11:30:54Z (GMT). No. of bitstreams: 1 PauloReniereSilvaDeSouza_DISSERT.pdf: 18420723 bytes, checksum: 0dee6d1653465093c4081165eec036ad (MD5) Previous issue date: 2016-07-22 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico (CNPq) / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES) / Dispers?es de complexos polieletrol?ticos (PEC) foram preparadas a partir de quitosana e poli(metacrilato de s?dio), atrav?s da mistura de suas solu??es, a diferentes raz?es molares carboxila/amino, rCA. O raio de giro foi determinado por SAXS e revelou que na medida que rCA aumentava as dimens?es das PEC?s decresciam, atingindo um m?nimo a rCA = 0.75, a qual foi considerada a raz?o na qual as dimens?es dos agregados eram m?nimas, sendo seguido de colapso e crescimento de part?culas maiores. Distribui??es de dist?ncia entre pares, P(r), tornaram-se mais estreitas at? rCA = 0.75, aumentando suas larguras a partir deste ponto. Par?metros relacionados ? relaxa??o, retirados de fun??es de correla??o de intensidade (ICF) de DLS identificaram tr?s processos principais de relaxa??o. O processo mais r?pido, relacionado a movimentos aleat?rios de mol?culas de polieletr?lito livres desapareceu, na medida em que rCA aumentou. Os outros dois processos de relaxa??o foram fun??es de rCA e apresentaram mudan?as caracter?sticas a rCA = 0.75. No mesmo valor de rCA, a energia de ativa??o para a taxa de relaxa??o m?dia indicou a ocorr?ncia de uma clara mudan?a na natureza das intera??es nas estruturas de PEC. O di?metro hidrodin?mico, determinado por DLS, foi muito maior que o raio de giro, determinado por SAXS. Part?culas de PEC podem ser descritas, consequentemente, como composta por um caro?o s?lido, rico em material segregado, insol?vel, envelopado por aglomerados sol?veis de PEC, possivelmente na forma de g?is altamente hidratados. / Polyelectrolyte complex (PEC) dispersions were prepared from chitosan and poly(sodium acrylate), NaPMA, by mixing their solutions., at different carboxyl to aminium molar ratio, rCA. Gyration radius was determined by SAXS and showed that, as rCA increased, PEC dimensions decreased and reached a minimum at rCA = 0.75, which was considered the ratio at which PEC cluster dimensions was minimum, following collapse and growth of larger particles. Pair distance distributions, P(r), became narrower up to rCA = 0.75, increasing its width from this point. Relaxation-related parameters from DLS intensity correlation functions (ICF) identified three main relaxation process. The fast process, related to free polyelectrolyte molecules random motion disappeared as rCA was increased. The other two relaxation process were a function of rCA and presented marked changes at rCA = 0.75. At the same value of rCA the energy of activation for the average relaxation rate showed the occurrence of a clear change in the nature of PEC-related interactions. As hydrodynamic diameter, determined by DLS was much larger than the gyration radius determined by SAXS, PEC particles could be described as being composed by a core, rich in segregated, insoluble material, enveloped by PEC soluble clusters, possibly in the form of water-rich gels.