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Browsing by Author "Resnik, Matic"

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  • Conductive bacterial cellulose-polyaniline blends: Influence of the matrix and synthesis conditions
    Publication . Alonso, Emanuel; Faria, Marisa; Mohammadkazemi, Faranak; Resnik, Matic; Ferreira, Artur; Cordeiro, Nereida
    Bacterial cellulose/polyaniline (BC/PANi) blends present a great potential for several applications. The current study evaluates the impact of using different BC matrixes (drained, freeze-dried and regenerated) and different synthesis conditions (in situ and ex situ) to improve the inherent properties of BC, which were monitored through FTIR-ATR, EDX, XRD, SEM, AFM, swelling, contact angle measurement and IGC. The employment of in situ polymerization onto drained BC presented the most conductive membrane (1.4 × 10-1 S/cm). The crystallinity, swelling capacity, surface energy and acid/base behavior of the BC membranes is substantially modified upon PANi incorporation, being dependent on the BC matrix used, being the freeze-dried BC blends the ones with highest crystallinity (up to 54%), swelling capacity (up to 414%) and surface energy (up to 75.0 mJ/m2). Hence, this work evidenced that the final properties of the BC/PANi blends are greatly influenced by both the BC matrixes and synthesis methods employed.
    2018Journal article Open access Show more
  • Physicochemical surface properties of bacterial cellulose/polymethacrylate nanocomposites: an approach by inverse gas chromatography
    Publication . Faria, Marisa; Vilela, Carla; Silvestre, Armando J.D.; Deepa, Bhanumathyamma; Resnik, Matic; Freire, Carmen S. R.; Cordeiro, Nereida
    Nanocomposites of poly(glycidyl methacrylate) and bacterial cellulose (BC), or poly(poly(ethylene glycol) methacrylate) and BC were produced via the in-situ polymerization of methacrylic monomers, inside the BC 3D network. The nanocomposites surface properties were evaluated by inverse gas chromatography (IGC). The dispersive component of surface energy (γsd) varied between 35.64 - 83.05 mJ m-2 at 25 °C. The surface of the different nanocomposites has a predominant basic character (Kb/Ka = 4.20-4.31). Higher specific interactions with polar probes were found for the nanocomposite bearing pendant epoxide groups, that apart from the low surface area (SBET = 0.83 m2 g-1) and monolayer capacity (nm = 2.18 μmol g-1), exhibits a high value of γsd (88.19 mJ m-2 at 20 °C). These results confirm the potential of IGC to differentiate between nanocomposites with different surface functional groups and to predict their potential interactions with living tissues, body fluids and other materials.
    2019Journal article Open access Show more