Browsing by Author "Odolczyk, Katarzyna"
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Item Open Access Coatings for the prevention of marine fouling(Cranfield University, 2016-10) Odolczyk, Katarzyna; Zhang, QiMicroorganisms attachment to the surfaces located in the marine water has become a significant problem. Historically, the antifouling properties of the coatings were achieved by using biocides, which had a negative consequence to the marine environment. Currently, alternative environmental friendly methods are required. This thesis aimed to investigate and produce the antifouling coatings that can be used as potential candidates in the marine industry. In this study, a range of novel polymer nanocomposite coatings was fabricated via the method of solvent and tested based on the strategy of microbial adhesion. The composition of the coatings mainly contains polidimethylsiloxane (PDMS) and different nanomaterials. The coatings applied on glass substrate were characterised using X-ray spectroscopy (XRD), scanning electron microscopy (SEM), contact angle measurements, inductively coupled plasma mass spectroscopy (ICP-MS) and atomic force microscopy (AFM). In biofouling assays, attachment of bacteria B. Subtilis and three marine microalgae (Skeletonema sp., Amphora sp., D. Salina) was investigated in laboratory scale. The obtained results suggested that small amount of nanoparticles in the polymer matrix can improve the antifouling settlement behaviour of the coatings. All microalgae attached more on PDMS/SiO2 and control surfaces (glass and PDMS) compared to the coatings containing multiwall carbon nanotubes (MWCNT) and sodium bismuth titanate (NBT). The influence of contact time, surface roughness and surface wettability was also studied. The microbial attachment varied significantly with respect to contact time and surface properties. There was no obvious evidence showing that the wetting properties and the roughness of the coatings have an effect on growth ... [cont.].Item Open Access Crystallization kinetics and enhanced dielectric properties of free standing lead-free PVDF based composite films(Elsevier, 2017-06-06) Meng, Nan; Mao, Rui; Tu, Wei; Odolczyk, Katarzyna; Zhang, Qi; Bilotti, Emiliano; Reece, Michael J.Ferroelectric composites, integrating dielectric ceramic fillers with mechanically flexible polymers, are promising materials for flexible electronic applications. Plenty of research has demonstrated the enhanced dielectric and ferroelectric properties of composite materials. However, the mechanisms responsible for these enhancements are not completely understood. Herein, we used typical dielectric materials, poly(vinylidene fluoride) (PVDF) and BaTiO3 (BTO), to study the effect of a dielectric filler on the crystallization, phase transformation and dielectric properties of PVDF. The crystallization of β-PVDF was not affected by the presence of BTO particles, but small amounts of BTO (<3 vol %) made PVDF crystallize into larger spherulites. This is linked to crystallization kinetic studies, which showed that BTO acted as a nucleation agent for large full ring banded spherulites when its content was less than 1 vol %. Furthermore, solid state drawing in the presence of BTO particles promoted the formation of β-PVDF with more pronounced preferred crystalline orientation at high drawing temperatures (120 °C). The dielectric and ferroelectric properties were enhanced with BTO filling. The 100 °C oriented drawn PVDF tape exhibited a dielectric permittivity of 14 (100 Hz) and remnant polarization of 0.080 C/m2 (10 Hz), which increased to 23 and 0.095 C/m2, respectively, after filling with 5 vol % BTO; neither resulting in high dielectric loss tangent (∼0.02) nor obvious current leakage. Moreover, the coercive field decreased from 80 to 50 kV/mm with increasing BTO content from 0 to 5 vol %.