Este trabalho teve por objetivo a produção de membranas porosas à base de carboximetilquitosana (CMQ) para serem empregadas no tratamento de lesões de pele. Inicialmente, β-quitina extraída de gládios de lula foi submetida a processo de desacetilação assistida por irradiação de ultrassom de alta intensidade (processo DAIUS), resultando em quitosana com grau médio de desacetilação (GD) 63 % e massa molecular média viscosimétrica (Mv) 10,3 ± 0,4 x 105 g mol-1. Carboximetilquitosana (CMQ) foi sintetizada sob condição heterogênea a partir da reação entre quitosana DAIUS e ácido monocloracético em meio alcalino por 4 horas a 30 °C, resultando em CMQ com Mv= 1,51 ± 0,06 x 105 g mol-1, graus médios de substituição e de desacetilação (GS) = 1,1 e GD= 70 %, respectivamente. Na segunda etapa do presente estudo, membranas porosas à base de CMQ e poli (álcool vinílico) (PVA) foram produzidas através de processo de liofilização de soluções aquosas de CMQ e PVA, ou de blendas contendo diferentes proporções mássicas CMQ/PVA, a saber 75/25, 50/50, 25/75. Em todos casos a concentração polimérica foi 0,5 % (m/v). As membranas foram caracterizadas quanto a morfologia, porosidade, capacidade de hidratação e propriedades mecânicas e térmicas (TG). Adicionalmente, foram avaliados os efeitos da reticulação com genipina nas propriedades físico-químicas e mecânicas das membranas. Os resultados dessa etapa revelaram que os materiais obtidos apresentaram superfícies porosas e poros interligados, exibindo elevadas porosidade (68,3 ± 2,5 % - 88,4 ± 1,12 %) e capacidade de hidratação (1080 ± 51 % - 2500 ± 27 %). Foi observado que a presença de PVA na blenda polimérica empregada para produzir as membranas CMQ/PVA resultou em materiais pouco solúveis em meio aquoso e termicamente mais estáveis quando comparados às membranas CMQ e PVA. Assim, a membrana preparada a partir da blenda com menor conteúdo de PVA (membrana (CMQ/PVA)75/25) exibiu maior estabilidade térmica quando comparada à membrana CMQ, sendo que estas apresentaram Tonset 280 °C e 264 °C, respectivamente. Os ensaios de tração revelaram que a partir de blendas ricas em PVA resultaram membranas mais resistentes, porém menos sujeitas a alongamento quando comparadas à membrana CMQ. Assim, as membranas (CMQ/PVA)75/25) e (CMQ/PVA)25/75 apresentaram valores de tensão na ruptura 2,6 ± 0,22 KPa e 20,91 ± 1,19 KPa, respectivamente, entretanto a última amostra apresenta menor capacidade de alongamento (5,38 ± 0,33 %) quando comparada à membrana CMQ (9,12 ± 0,62 %). De maneira geral, o processo de reticulação permitiu a obtenção de membranas estáveis em meio aquoso, e também mais porosas e mais resistentes, como as membranas R(CMQ/PVA)75/25), cuja porosidade é 88,4 ± 1,12 %, e R(CMQ), cuja tensão na ruptura é 42,18 ± 2,10 KPa. Contudo, as membranas reticuladas apresentaram menores estabilidade térmica, capacidade de absorção de água (1062,4 ± 18,2 % (R(CMQ/PVA)25/75)) e de alongamento (1,62 ± 0,23 % (R(CMQ/PVA)75/25)). Os resultados obtidos nessa etapa do estudo indicaram que, as membranas que apresentaram maior potencial para aplicação como curativo para lesões de pele foram a composta somente por CMQ reticulada com genipina (R(CMQ)) e aquela não-reticulada constituída por CMQ/PVA na proporção mássica de 25/75 ((CMQ/PVA)25/75). Com o objetivo de potencializar a sua utilização no tratamento de lesões de pele e conferir novas propriedades às membranas R(CMQ) e (CMQ/PVA)25/75, nanopartículas de ZnO ou de TiO2 foram adicionadas a essas formulações em diferentes proporções em relação à massa total de polímero, a saber 1 %, 2,5 % e 5 %, totalizando quatro novos conjuntos de amostras. Além das caracterizações físico-químicas e mecânicas, os quatro novos conjuntos de membranas também foram submetidos a ensaios in vitro de suscetibilidade à degradação enzimática e de citotoxicidade em relação à linhagem de células de fibroblastos Balb/C 3T3 clone A 31. Os resultados dessa etapa revelaram que a incorporação de nanopartículas resultou em membranas com poros mais definidos e com maior capacidade de absorção de água, a qual atingiu 3326 ± 106 % no caso da membrana (CMQ/PVA)25/75_5TiO2. Em relação à propriedades térmicas e mecânicas, os conjuntos se comportaram de maneiras diferentes de acordo com a natureza e o teor de nanopartículas e em função do material de partida. Assim, os valores de Tonset das membranas R(CMQ)_5ZnO, R(CMQ)_5TiO2 e R(CMQ) são 273 °C, 280 °C e 243 °C, respectivamente, revelando que a estabilidade térmica foi favorecida pela presença de elevado teor de nanopartículas de ZnO ou de TiO2. Entretanto, os valores de Tonset das membranas (CMQ/PVA)25/75 e (CMQ/PVA)25/75_5TiO2 foram 280 °C e 243 °C, respectivamente, revelando que a estabilidade térmica foi desfavorecida pela presença de nanopartículas de TiO2, o que não ocorreu quando nanopartículas de ZnO foram incorporadas, sugerindo a ocorrência de processo de degradação de PVA, possivelmente catalisado por TiO2. Os ensaios de tração indicam que as nanopartículas podem não estar homogeneamente dispersas na maioria das membranas estudadas, pois os resultados não permitem racionalizar tendências de comportamentos mecânicos em função da natureza e do teor de nanopartículas, e em função da membrana considerada. Assim, no caso da membrana (CMQ/PVA)25/75, a inserção de carga elevada (5 %) de nanopartículas de TiO2 resultou em membrana mais resistente à tração, mas a incorporação de teores medianos (2,5 %) de nanopartículas de ZnO tornou tal membrana mecanicamente mais frágil, o que também foi observado no caso da membrana R(CMQ), mesmo quando teor elevado de nanopartículas de TiO2 foi incorporado. A capacidade de alongamento das membranas também foi afetada pela natureza e teor de nanopartículas, mas também nesse caso não são observadas tendências claras. Desta forma, no caso das membranas (CMQ/PVA)25/75, com nanopartículas tanto de ZnO quanto de TiO2, assim como para a membrana R(CMQ) com nanopartículas de ZnO, a inserção das nanopartículas resultou em membranas com maior capacidade de alongamento. Já a incorporação de nanopartículas de TiO2 nas membranas R(CMQ) gerou membranas com menor capacidade de alongamento. Por outro lado, a presença de nanopartículas nas membranas não afetou a susceptibilidade à degradação enzimática, sendo verificado que apenas a composição da matriz polimérica influenciou a estabilidade das membranas. As membranas compostas somente por CMQ reticuladas com genipina degradaram completamente após quatro dias, ao passo que as amostras contendo PVA, independentemente da presença de nanopartículas ou de reticulação com genipina, foram apenas parcialmente susceptíveis à ação da enzima. Por fim, todas as amostras, com exceção da amostra R(CMQ)_5ZnO, se mostraram atóxicas em relação a fibroblastos Balb/C 3T3 clone A 31. De forma geral, as membranas constituídas por CMQ/PVA contendo nanopartículas de ZnO ou de TiO2 exibiram características físico-químicas, mecânicas e biológicas mais promissoras quando considerada a potencial aplicação desses materiais como curativos para lesões de pele. / This work aimed to produce porous carboxymethylchitosan-based membranes to be used in the treatment of skin lesions. Thus, β-chitin extracted from squid pens was subjected to ultrasound assisted deacetylation (USAD process), resulting in USAD chitosan with acetylation degree (GD) 63% and viscosity-average molecular weight (Mv) 10.3 ± 0.4 x 105 g mol-1. Carboxymethylchitosan (CMCh) was synthesized under heterogeneous condition from the reaction between USAD chitosan and monochloroacetic acid in alkaline medium for 4 hours at 30 °C, resulting in CMCh with Mv= 1,51 ± 0,06 x 105 g mol -1, average degrees of substitution and deacetylation (GS) = 1,1 and GD= 70 %, respectively. In the second step of the present study, porous membranes based on CMCh and polyvinyl alcohol (PVA) were produced by freeze-drying aqueous solutions of CMQ and PVA, or blends containing different weight ratios CMCh/PVA, namely 75/25, 50/50, 25/75. In all cases the polymer concentration was 0.5% (w/v). The membranes were characterized with respect to morphology, porosity, hydration capacity and mechanical and thermal properties (TG). Additionally, the effects of crosslinking with genipin on the physicochemical and mechanical properties of membranes were evaluated. The results of this step revealed that the materials presented porous surfaces and interconnected pores, exhibiting high porosity (68.3 ± 2.5% - 88.4 ± 1.12%) and swelling capacity (1080 ± 51% - 2500 ± 27%). It was observed that the presence of PVA in the polymer blends employed to produce the CMCh/PVA membranes resulted in materials poorly soluble in aqueous medium and thermally more stable as compared to CMCh and PVA membranes. Thus, the membrane prepared from the blends with lower content of PVA (membrane (CMCh/PVA)75/25) showed higher thermal stability when compared to the CMCh membrane, which presented Tonset 280 ° C and 264 ° C, respectively. The tensile tests showed that from PVA rich blends, the membranes were more resistant were produced, but less subject to elongation as compared to the CMCh membrane. Thus, the membranes (CMCh/PVA)75/25) and (CMCh/PVA)25/75 presented rupture tensile values of 2.6 ± 0.22 KPa and 20.91 ± 1.19 KPa, respectively. The latter sample presented a lower elongation capacity (5.38 ± 0.33%) as compared to the CMCh membrane (9.12 ± 0.62%). In general, the crosslinking process allowed to obtain membranes stable in aqueous media, and also more porous and more resistant, such as membranes R(CMCh/PVA)75/25, whose porosity is 88.4 ± 1.12 %, and R(CMCh), whose tensile strength at break is 42.18 ± 2.10 KPa. However, the crosslinked membranes presented lower thermal stability, water absorption capacity (1062.4 ± 18.2 % (R(CMCh/PVA)25/75)) and elongation (1.62 ± 0.23% (R(CMCh/PVA)75/25)). The results obtained in this stage of the study indicated that the membranes that presented the greatest potential for application as a curative for skin lesions were composed only of CMCh reticulated with genipine (R(CMCh)) and the non-reticulated CMCh/PVA mass ratio of 25/75 ((CMCh/PVA)25/75). In order to potentiate its use in the treatment of skin lesions and confer new properties on R(CMCh) and (CMCh/PVA)25/75 membranes, ZnO or TiO2 nanoparticles were added to these formulations in different proportions in relation to the total polymer mass, to know, 1%, 2.5% and 5%, totaling four new sets of samples. In addition to the physicochemical and mechanical characterization, the four new membrane sets were also submitted to in vitro enzymatic degradation susceptibility tests with respect to the Balb / C 3T3 fibroblast cell line clone A 31. The results of this step revealed that the incorporation of nanoparticles resulted in membranes with more defined pores and with greater water absorption capacity, which reached 3326 ± 106 % in the case of the membrane (CMCh/PVA)25/75_5TiO2. Regarding the thermal and mechanical properties, the assemblies behaved differently according to the nature and content of nanoparticles and as a function of the membrane composition. Thus, the Tonset values of membranes R(CMCh)_5ZnO, R(CMCh)_5TiO2 and R(CMCh) are 273 °C, 280 °C and 243 °C, respectively, showing that thermal stability was favored by the presence of high content of ZnO or TiO2 nanoparticles. However, Tonset values of the membranes (CMCh/PVA)25/75 and (CMCh/PVA)25/75_5TiO2 were 280 °C and 243 °C, respectively, showing that thermal stability was disadvantaged by the presence of nanoparticles of TiO2, which did not occur when nanoparticles of ZnO were incorporated, suggesting the occurrence of a degradation process of PVA, possibly catalyzed by TiO2. The tensile tests indicate that the nanoparticles may not be homogeneously dispersed in most of the studied membranes, because the results do not allow to rationalize tendencies of mechanical behavior according to the nature and content of nanoparticles, and depending on the membrane considered. Thus, in the case of the membrane (CMCh/PVA)25/75, the high load insertion (5%) of TiO2 nanoparticles resulted in a more tensile membrane, but the incorporation of medium contents (2.5%) of nanoparticles of ZnO made such a membrane mechanically more fragile, which was also observed in the case of membrane R(CMCh), even when high content of TiO2 nanoparticles was incorporated. The elongation capacity of the membranes was also affected by the nature and content of nanoparticles, but also in this case no clear trends were observed. Thus, in the case of membranes (CMCh/PVA)25/75, with nanoparticles of both ZnO and TiO2, as well as for membrane R(CMCh) with nanoparticles of ZnO, the insertion of the nanoparticles resulted in membranes with greater capacity of stretching. Already the incorporation of TiO2 nanoparticles in membranes R(CMCh) generated membranes with less capacity of elongation. Already the incorporation of TiO2 nanoparticles in the membranes R(CMCh) generated membranes with less capacity of elongation. The presence of nanoparticles in the membranes did not affect the susceptibility to enzymatic degradation, being verified that only the composition of the polymer matrix influenced the stability of the membranes. Membranes composed only of CMCh crosslinked with genipine completely degraded after four days, whereas samples containing PVA, regardless of the presence of nanoparticles or crosslinking with genipine, were not susceptible to the action of the enzyme. Finally, all samples, except for sample R(CMCh)_5ZnO, were shown to be nontoxic in relation to Balb / C 3T3 fibroblasts clone A 31. In general, membranes consisting of CMCh/PVA containing ZnO nanoparticles or of TiO2 exhibited the most promising physical-chemical, mechanical and biological characteristics when considering the potential application of these materials as curatives for skin lesions.

Submitted by Rafael Santana (rafael.silvasantana@ufpe.br) on 2017-07-10T18:06:04Z No. of bitstreams: 2 license_rdf: 811 bytes, checksum: e39d27027a6cc9cb039ad269a5db8e34 (MD5) Dissertação_Cecília.pdf: 3721060 bytes, checksum: cd2515bc852d6c7bb0fadaeef5673702 (MD5) / Made available in DSpace on 2017-07-10T18:06:04Z (GMT). No. of bitstreams: 2 license_rdf: 811 bytes, checksum: e39d27027a6cc9cb039ad269a5db8e34 (MD5) Dissertação_Cecília.pdf: 3721060 bytes, checksum: cd2515bc852d6c7bb0fadaeef5673702 (MD5) Previous issue date: 2016-01-22 / CNPQ / Este trabalho tem como objetivo analisar propriedades magnéticas de arranjos ordenados de nanofios de níquel depositados em membranas porosas de alumina. Um estudo sobre a preparação das amostras, relatando as etapas de formação da membrana e posterior eletrodeposição dos fios via corrente alternada, é feito inicialmente. Na sequência, características morfológicas e estruturais são observadas via microscopia eletrônica de varredura e mapas de energia dispersiva, de onde foi possível constatar que os fios possuíam diâmetros entre 30 nm e 40 nm e comprimentos entre 100 nm e 550 nm. As análises das propriedades magnéticas das amostras são baseadas nas curvas de histerese obtidas via magnetometria de amostra vibrante para diferentes direções de campo aplicado e de temperatura. O caráter de anisotropia magnética uniaxial que esses sistemas de nanofios possuem é observado através destas curvas, bem como o efeito que a interação dipolar entre os fios causa nas propriedades magnéticas do sistema. O laço de histerese nos fornece parâmetros magnéticos como coercividade e remanência e uma análise sobre seus comportamentos em função de parâmetros geométricos e morfológicos dos fios, direção de campo aplicado e temperatura são realizadas e comparadas com os resultados reportados na literatura. / This work aims to analyze magnetic properties of nickel nanowires arrays electrodeposited on porous anodic alumina membrane. A study of sample preparation is reported initially and then morphological and structural features are observed via scanning electron microscopy, from which we observe wires with diameters between 30 nm and 40 nm and lengths between 100 nm and 550 nm. The analysis of the magnetic properties are based on the hysteresis curves for different directions of applied field and temperature. The uniaxial magnetic anisotropy is observed as well the effect of the dipolar interaction between the wires. These curves also provides the magnetic parameters such as coercivity and remanence and we analyze their behavior as a function of geometric and morphological parameters, applied field direction and temperature, comparing with the results reported in the literature.

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Made available in DSpace on 2014-12-17T14:07:17Z (GMT). No. of bitstreams: 1 KesiaKOS_TESE_PARCIAL.pdf: 625810 bytes, checksum: ba2f0bf53a4151666220c09ffd2f2947 (MD5) Previous issue date: 2013-07-01 / Textile production has been considered as an activity of high environmental impact due to the generation of large volumes of waste water with high load of organic compounds and strongly colored effluents, toxic and difficult biodegradability. This thesis deals with obtaining porous alumina ceramic membranes for filtration of textile effluent in the removal of contaminants, mainly color and turbidity. Two types of alumina with different particle sizes as a basis for the preparation of formulation for mass production of ceramic samples and membranes. The technological properties of the samples were evaluated after using sintering conditions: 1,350?C-2H, 1,450?C-30M, 1,450?C-2H, 1,475?C-30M and 1,475?C-2H. The sintered samples were characterized by XRD, XRF, AG, TG, DSC, DL, AA, MEA, RL, MRF-3P, SEM and Intrusion Porosimetry by Mercury. After the characterization, a standard membrane was selected with their respective sintering condition for the filterability tests. The effluent was provided by a local Textile Industry and characterized at the entry and exit of the treatment plant. A statistical analysis was used to study the effluent using the following parameters: pH, temperature, EC, SS, SD, oil and grease, turbidity, COD, DO, total phosphorus, chlorides, phenols, metals and fecal coliform. The filtered effluent was evaluated by using the same parameters. These results demonstrate that the feasibility of the use of porous alumina ceramic membranes for removing contaminants from textile effluent with improved average pore size of 0.4 micrometre (distribution range varying from 0,025 to 2.0 micrometre), with total porosity of 29.66%, and average percentages of color removal efficiency of 89.02%, 92.49% of SS, turbidity of 94.55%, metals 2.70% (manganese) to 71.52% (iron) according to each metal and COD removal of 72.80% / A produ??o t?xtil tem sido considerada uma atividade de alto impacto ambiental, devido ? gera??o de grandes volumes de rejeitos com alta carga de compostos org?nicos e efluente fortemente colorido, t?xico e dif?cil biodegradabilidade. O presente trabalho trata da obten??o de membranas cer?micas porosas de alumina para filtra??o de efluente industrial t?xtil na remo??o de contaminantes, em especial, cor e turbidez. Utilizou-se dois tipos de alumina com granulometrias diferentes como base para o preparo de formula??es de massas cer?micas para a produ??o dos corpos de prova e membranas. As propriedades tecnol?gicas dos corpos de prova foram avaliadas ap?s suas sinteriza??es nas condi??es de: 1.350?C 2H, 1.450?C 30M, 1.450?C 2H, 1.475?C 30 M e 1.475?C 2H. Foram caracterizadas por DRX, FRX, AG, TG, DSC, DL, AA, MEA, RL, MRF-3P, MEV e Porosimetria por Intrus?o de Merc?rio. Ap?s essa caracteriza??o definiu-se uma membrana padr?o, com a sua respectiva condi??o de sinteriza??o, para os ensaios de filtrabilidade. O efluente foi fornecido por uma Ind?stria t?xtil do RN, e caracterizado nos pontos de entrada e sa?da da ETE. Utilizou-se um tratamento estat?stico dos resultados analisados no efluente atrav?s dos seguintes par?metros: pH, temperatura, CE, SS, SD, ?leos e graxas, turbidez, DQO, OD, f?sforo total, cloretos, fen?is, metais e coliformes termotolerantes. O permeado (EF) foi avaliado pelos mesmos par?metros. Os resultados obtidos demonstram a viabilidade no uso de membranas cer?micas porosas de alumina na remo??o de contaminantes de efluente industrial t?xtil, com melhor tamanho m?dio de poro de 0,4?m (faixa de distribui??o de tamanhos de poros variando de 0,025 a 2 ?m), com porosidade total de 29,66%, com percentuais m?dios de efici?ncia na remo??o de cor de 89,02%, SS de 92,49%, turbidez de 94,55%, metais variando de 2,70% (mangan?s) at? 71,52% (ferro) de acordo com cada metal e remo??o de DQO de 72,80% / 2020-01-01

La dépollution de l'eau est un des enjeux majeurs du XXIème siècle. Si différentes techniques de retraitement existent déjà, nous investiguons une nouvelle méthode associant les propriétés des membranes filtrantes à celles des matériaux photocatalytiques. Ainsi, nous avons étudié la croissance et l'activité photocatalytique de structures de type noyau/coquille de ZnO/SnO2 intégrées dans des membranes méso-poreuses (alumine poreuse) et macro-poreuses (fibres de verre). L'activité photocatalytique de ces matériaux a été évaluée sur des polluants modèles tels que le bleu de méthylène ou l'acide salicylique, mais aussi sur des polluants organiques identifiés dans les eaux de la rivière luxembourgeoise Alzette. L'impact environnemental des matériaux développés a été déterminé grâce a des analyses de cytotoxicité sur des cellules colorectales de type Caco-2, ainsi que sur des bactéries marines de type Vibrio Fischeri. / Water treatment is one of the main challenge to overcome on the XXIst century. If many different techniques already exist, we investigate a new process associating the properties of porous membranes and photocatalytic materials. Thus, we studied the growth and photoactivity of core/shell structures of ZnO/SnO2 integrated into mesoporous (AAO) and macro-porous (glass fiber) membranes . The photocatalytic activity of these materials has been evaluated on organic pollutants like methylene blue or salicylic acid, but also on molecules found in the Luxembourgish Alzette river. The environmental impact of the synthesized structures has been determined with cytotoxic analyses on Caco-2 cells and Vibrio Fischeri bacteria.

Submitted by Emanuel Varela Cardoso (emanuel.varela@ufcg.edu.br) on 2018-06-13T20:55:07Z No. of bitstreams: 1 PAULA CHRISTIANNE GOMES GOUVEIA SOUTO MAIA – DISSERTAÇÃO (PPG-CEMat) 2015.pdf: 2231072 bytes, checksum: ae7116b6547ccb83d6170ccf2e265c42 (MD5) / Made available in DSpace on 2018-06-13T20:55:07Z (GMT). No. of bitstreams: 1 PAULA CHRISTIANNE GOMES GOUVEIA SOUTO MAIA – DISSERTAÇÃO (PPG-CEMat) 2015.pdf: 2231072 bytes, checksum: ae7116b6547ccb83d6170ccf2e265c42 (MD5) Previous issue date: 2015-06-19 / O estudo sobre sistema de liberação controlada de fármaco está em constante crescimento, pois visa melhorar e prolongar o controle da administração de fármacos. Insulina oral é um sonho dos pacientes e um desafio para os cientistas. Para os doentes, não é apenas o alívio da dor da aplicação de múltiplas injeções, mas também a proteção das células betas do pâncreas. A quitosana é um biomaterial considerado atóxico, não alergênica, biodegradável, biofuncional, biocompatível e as suas atividades biológicas compreendem a ação antioxidante, antimicrobiana, analgésica, aceleração da cicatrização, anti-inflamatórias além de ser muito estudada como matriz polimérica em sistemas de liberação controlada de fármacos. A gelatina por sua vez está sendo muito utilizada na área farmacêutica com a finalidade de favorecer o intumescimento do sistema e consequentemente acelerar o processo de liberação. Sendo assim, este trabalho teve como objetivo desenvolver membranas de quitosana, gelatina e insulina para uso em sistema de liberação controlada de fármacos. As membranas desenvolvidas foram caracterizadas pelas técnicas de Difração de raios-X (DRX), Espectroscopia na Região de Infravermelho com Transformada de Fourier (FTIR), Microscopia Eletrônica de Varredura (MEV) com Espectroscopia por Energia Dispersiva de raios X (EDS) e Microscopia Óptica (MO). Na técnica de DRX verificou que o que não ocorreu alteração significativa na cristalinidade das membranas. Com a técnica de FTIR verificou que a gelatina, insulina e o tripolifosfato de sódio não interferiram nos grupos funcionais de superfície da quitosana, mantendo desta forma as propriedades da mesma. No EDS foi possível detectar os elementos químicos característicos do material. Foi possível perceber, através das técnicas de MO e MEV, alteração na morfologia da membrana contendo insulina, gelatina e tripolifosfato de sódio quando comparada a de quitosana pura. Baseado nos resultados pode-se concluir que a insulina foi encapsulada pela quitosana e que a presença da gelatina influenciou no tamanho e forma dos poros das membranas e que a neutralização com NaOH diminuiu a quantidade de aglomerados nas superfícies dos arcabouços reticulados com tripolifosfato de sódio. / The study of drug controlled release system is constantly growing, it aims to improve and extend the control of drug administration. Oral insulin is a dream of patients and a challenge for scientists. For patients, it's not just pain relief applying multiple injections, but also the protection of beta cells of the pancreas. Chitosan, a biomaterial is considered non-toxic, non-allergenic, biodegradable, biofunctional, biocompatible and their biological activities include the antioxidant action, antimicrobial, analgesic, acceleration of wound healing, anti-inflammatory as well as being widely studied as polymer matrix systems controlled drug release. Gelatin turn is being widely used in the pharmaceutical field for the purpose of favoring the system swelling and consequently accelerate the release process. Thus, this study aimed to develop chitosan membranes, gelatin and insulin for use in controlled release system of drugs. The developed membranes were characterized by powder Diffraction X-ray (XRD), spectroscopy in the infrared region with a Fourier transform (FTIR) analysis, Scanning Electron Microscopy (SEM) with Energy Dispersive Spectroscopy X-ray (EDS) and Microscopy optical (MO). In XRD technique we found that what was no significant change in the crystallinity of the membranes. With FTIR technique found that gelatin, insulin and sodium tripolyphosphate did not affect the surface functional groups of chitosan, thereby maintaining the properties thereof. The EDS was possible to detect the characteristic chemical elements of the material. It was possible to see, through the techniques of OM and SEM, change in morphology of the membrane containing insulin, gelatin and sodium tripolyphosphate compared to pure chitosan. Based on the results it can be concluded that insulin was encapsulated by chitosan and the presence of the gelatin influence the size and shape of the pores of the membranes and neutralization with NaOH decreased the amount of agglomerates on the surfaces of scaffolds crosslinked with sodium tripolyphosphate.

Spreading of mixtures of oil with suitable silica particles onto a water surface leads to the formation of composite layers in which particles protrude at the top and at the bottom from the oil. Solidification of the oil and removal of the particles give rise to porous membranes. Pore widths and membrane thicknesses depend on particle sizes and usually are in the range of 70 – 80% of their diameters. Often freely suspended porous membranes are too fragile to operate them in pressure filtration without supportive structure. To improve mechanical stability of porous membranes, a mixture of silica particles with an oil is spread onto a nonwoven fibrous support that was drenched with water. Solidification of the oil and removal of particles yields porous membrane attached to the fibers of the support. Due to inhomogeneous surface of the fabric, the membranes that are attached to it are corrugated. To obtain flat supportive structures, glass beads with 75 μm in diameter are spread onto the water surface with the oil. Solidification of the oil and then removal of particles gives rise to porous membranes with pore diameters in micrometer range. Another concept of improvement of mechanical stability is the preparation of asymmetric membranes via spreading of a mixture of two sorts of particles with opposite surface properties with the oil onto the water surface. After solidification of the oil and removal of particles, membranes with pores width in the range from 30 – 50 nm are obtained. Slow removal of silica particles from composite monolayer that floats on the water surface gives rise to silica rings in intermediate stages of removal. Mixed matrix membranes with embedded carbon molecular sieves are prepared in a similar process as detailed above by using carbon particles instead of silica. Carbon molecular sieves protrude at the top and bottom from the polymeric matrix. Theoretical prediction of permeability and selectivity through these membranes are much higher than in membranes where particles are smaller than the membrane thickness. / Spreitet man Mischungen eines Öls mit geeigneten Kieselgelpartikeln auf eine Wasseroberfläche, führt dies zur Bildung gemischter Schichten, in denen die Partikel auf der Ober- und Unterseite aus dem Öl herausragen. Härtet man das Öl aus und entfernt die Partikel, erhält man poröse Membranen mit einheitlichen Poren. Dabei hängen die Porenweiten und Membrandicken von der Partikelgröße ab und betragen üblicherweise 70 – 80 % von deren Durchmesser. Oft sind freitragende poröse Membranen zu zerbrechlich um mit ihnen Druckfiltration ohne Stützstruktur durchzuführen. Um die mechanische Stabilität von porösen Membranen zu erhöhen spreitet man eine Mischung aus Kieselgelpartikeln und einem Öl auf einem Vliesstoff, der mit Wasser getränkt ist. Das Aushärten des Öls und die Entfernung der Partikel führt zu einer porösen Membran, die an die Fasern der Stützstruktur angeheftet ist. Durch die inhomogene Oberfläche des Vliesgewebes sind die daran angehefteten Membranen gewellt. Um eine ebene Stützstruktur zu erhalten, werden Mischungen aus dem Öl und Glaskugeln mit einem Durchmesser von 75 μm verwendet. Das Aushärten des Öls und die Entfernung der Partikel führt zu ebenen porösen Membranen mit Porendurchmessern im Mikrometerbereich. Ein weiteres Konzept, um die mechanische Stabilität zu erhöhen, ist die Herstellung asymmetrischer Membranen mit Hilfe des Spreitens einer Mischung zweier Partikelsorten mit unterschiedlichen Oberflächeneigenschaften mit dem Öl auf die Wasseroberfläche. Nach dem Aushärten des Öls und der Entfernung der Partikel erhält man eine asymmetrische Membran mit kleinen Porenweiten an der Oberseite und großen Porenweiten an der Unterseite. Durch langsames Entfernen der Kieselgelpartikel aus der gemischten Schicht, die auf der Wasseroberfläche schwimmt, kann man in einem Zwischenstadium Kieselgelringe erhalten. Kompositmembranen (mixed matrix membranes) mit eingebetteten Kohlenstoffmolekularsieben werden in einem gleichen Prozess wie oben beschrieben hergestellt, indem man Kohlenstoffpartikel anstatt der Kieselgelpartikel verwendet. Die Kohlenstoffmolekularsiebe ragen auf der Ober- und Unterseite aus der Polymermatrix heraus. Die theoretisch vorhersagten Durchlässigkeiten und Selektivitäten solcher Membranen sind wesentlich höher als bei Membranen, in denen die Partikel kleiner als der Membrandicke sind.

Poröse Polymermembranen spielen in der Industrie und Forschung als Filtrationsmedien eine bedeutende Rolle. Eine besondere Form dieser Membranen sind die sogenannten Mikrosiebe, die sich im Vergleich zu herkömmlichen Filtermedien durch eine Membrandicke kleiner als der Durchmesser der Poren, eine enge Porengrößenverteilung und eine hohe Porendichte auszeichnen. Dies führt zu einer hohen Selektivität und Permeabilität dieser Mikrosiebe. Aufgrund der geringen Membrandicke sind sie jedoch, beispielsweise beim Einsatz als Filtermedien, sehr empfindlich gegenüber mechanischer Belastung und benötigen üblicherweise eine zusätzliche (externe) Stützstruktur. Die vorliegende Arbeit beschäftigt sich mit der Herstellung mikrosiebartiger Polymermembranen, bei denen die Darstellung der späteren Trennschicht und Stützstruktur in einem Prozess erfolgt – den hierarchisch strukturierten porösen Membranen. Es werden zwei neue Verfahren zur Darstellung dieser Membranen vorgestellt. Im ersten Verfahren wird das Prinzip der partikel-assistierten Benetzung mit den sogenannten Kondensationsmustern (Breath Figures Patterns), im zweiten Verfahren mit der Tintenstrahltechnik kombiniert. In beiden Fällen enthalten die resultierenden Polymermembranen die gewünschte hierarchische Porenstruktur, d. h. sie weisen eine Trennschicht mit submikrometergroßen Poren auf der einen Seite und eine Stützstruktur mit größeren, mikrometergroßen Poren auf der anderen Seite auf. Um die Membranen, welche durch Kombination der partikel-assistierten Benetzung mit den Kon-densationsmustern hergestellt werden, für einen möglichen Einsatz als Filtrationsmedium zu charakterisieren, werden Untersuchungen bezüglich des Permeatflusses und der Permeabilität sowie zum Rückhaltevermögen durchgeführt.

Spreading of mixtures of oil with suitable silica particles onto a water surface leads to the formation of composite layers in which particles protrude at the top and at the bottom from the oil. Solidification of the oil and removal of the particles give rise to porous membranes. Pore widths and membrane thicknesses depend on particle sizes and usually are in the range of 70 – 80% of their diameters. Often freely suspended porous membranes are too fragile to operate them in pressure filtration without supportive structure. To improve mechanical stability of porous membranes, a mixture of silica particles with an oil is spread onto a nonwoven fibrous support that was drenched with water. Solidification of the oil and removal of particles yields porous membrane attached to the fibers of the support. Due to inhomogeneous surface of the fabric, the membranes that are attached to it are corrugated. To obtain flat supportive structures, glass beads with 75 μm in diameter are spread onto the water surface with the oil. Solidification of the oil and then removal of particles gives rise to porous membranes with pore diameters in micrometer range. Another concept of improvement of mechanical stability is the preparation of asymmetric membranes via spreading of a mixture of two sorts of particles with opposite surface properties with the oil onto the water surface. After solidification of the oil and removal of particles, membranes with pores width in the range from 30 – 50 nm are obtained. Slow removal of silica particles from composite monolayer that floats on the water surface gives rise to silica rings in intermediate stages of removal. Mixed matrix membranes with embedded carbon molecular sieves are prepared in a similar process as detailed above by using carbon particles instead of silica. Carbon molecular sieves protrude at the top and bottom from the polymeric matrix. Theoretical prediction of permeability and selectivity through these membranes are much higher than in membranes where particles are smaller than the membrane thickness. / Spreitet man Mischungen eines Öls mit geeigneten Kieselgelpartikeln auf eine Wasseroberfläche, führt dies zur Bildung gemischter Schichten, in denen die Partikel auf der Ober- und Unterseite aus dem Öl herausragen. Härtet man das Öl aus und entfernt die Partikel, erhält man poröse Membranen mit einheitlichen Poren. Dabei hängen die Porenweiten und Membrandicken von der Partikelgröße ab und betragen üblicherweise 70 – 80 % von deren Durchmesser. Oft sind freitragende poröse Membranen zu zerbrechlich um mit ihnen Druckfiltration ohne Stützstruktur durchzuführen. Um die mechanische Stabilität von porösen Membranen zu erhöhen spreitet man eine Mischung aus Kieselgelpartikeln und einem Öl auf einem Vliesstoff, der mit Wasser getränkt ist. Das Aushärten des Öls und die Entfernung der Partikel führt zu einer porösen Membran, die an die Fasern der Stützstruktur angeheftet ist. Durch die inhomogene Oberfläche des Vliesgewebes sind die daran angehefteten Membranen gewellt. Um eine ebene Stützstruktur zu erhalten, werden Mischungen aus dem Öl und Glaskugeln mit einem Durchmesser von 75 μm verwendet. Das Aushärten des Öls und die Entfernung der Partikel führt zu ebenen porösen Membranen mit Porendurchmessern im Mikrometerbereich. Ein weiteres Konzept, um die mechanische Stabilität zu erhöhen, ist die Herstellung asymmetrischer Membranen mit Hilfe des Spreitens einer Mischung zweier Partikelsorten mit unterschiedlichen Oberflächeneigenschaften mit dem Öl auf die Wasseroberfläche. Nach dem Aushärten des Öls und der Entfernung der Partikel erhält man eine asymmetrische Membran mit kleinen Porenweiten an der Oberseite und großen Porenweiten an der Unterseite. Durch langsames Entfernen der Kieselgelpartikel aus der gemischten Schicht, die auf der Wasseroberfläche schwimmt, kann man in einem Zwischenstadium Kieselgelringe erhalten. Kompositmembranen (mixed matrix membranes) mit eingebetteten Kohlenstoffmolekularsieben werden in einem gleichen Prozess wie oben beschrieben hergestellt, indem man Kohlenstoffpartikel anstatt der Kieselgelpartikel verwendet. Die Kohlenstoffmolekularsiebe ragen auf der Ober- und Unterseite aus der Polymermatrix heraus. Die theoretisch vorhersagten Durchlässigkeiten und Selektivitäten solcher Membranen sind wesentlich höher als bei Membranen, in denen die Partikel kleiner als der Membrandicke sind.