Magdalena Laskowska

Influence of the Copper-Containing SBA-15 Silica Fillers on the Mechanical Properties of High Density Polyethylene

The paper concerns the mechanical properties of the high density polyethylene (HDPE) with the copper-containing SBA-15 silica filler. The considered filler is the SBA-15 mesoporous silica containing copper ions bounded inside channels via propyl-phosphonate anchoring groups. With its help, we can impart the biocidal properties to this plastic. Research covered mechanical properties, thermal analysis, colour, shine, and nanomolecular structure. Dynamical properties of the samples like modulus changes and mechanical core loss angle tangent versus temperature and vibration frequency were tested using DMTA method. Level of crystallinity was tested using DSC method while their structure was observed with going through light by optical microscope. Hardness and toughness of obtained samples were also defined. Colour and shine changes of the samples were observed for PE-HD with filler contents 0.5% and 1%. Modulus value changes versus temperature and frequency were notified for the samples with modifier. There were no differences in modulus changes versus temperature for samples with and without filler and frequencies 1 and 10 Hz. It was detected that melting enthalpy of the samples with the modifier decreases. Moreover, some influence of the samples with filler on colour and shine was observed.

New Class of Antimicrobial Agents

The paper is about a new class of antimicrobial functional nanomaterials. Proposed compounds are based on SBA-15 porous silica matrices and contain anchored copper ions. Thanks to the immobilization of functional groups the compounds are safer for environment than commonly used disinfectant agents. We prepared and examined silica based materials containing two concentrations of copper-containing groups: 10 and 5%. For the reference we prepared samples containing free-standing CuO molecules in the structure and checked their antimicrobial properties. Antibacterial effect of considered SBA-15-Cu material was tested on Escherichia coli bacteria. Antimicrobial tests were applied for the pure form of the material and as modifying agents for plastics. The obtained results showed that the sample with lower concentration of active copper-containing groups has stronger antimicrobial properties than the one with higher concentration of copper. Interestingly, silica containing free-standing CuO molecules has no antimicrobial properties. Considering the obtained results, we can conclude that the most probable antimicrobial mechanism in this case is an oxidation stress. When a plastic modifier is applied the material is enriched with bacterial inhibitory properties. It seems that SBA-15 silica containing low concentration of anchored copper ions is promising in terms of its antibacterial property and biomaterial potential for commercial use.

Mesoporous Silica Functionalized by Nickel-Cyclam Molecules: Preparation and Resonance Raman Study

Abstract Mesoporous silica SBA-15 functionalized by (1,4,8,11-tetraazacyclotetradecane) cyclam groups containing nickel ions (Ni-cyclam) was synthesized by two different approaches, and investigated by resonance Raman spectroscopy. Vibrational features of organometallic moleculess are analyzed for (Ni-cyclam) groups grafted in the silica pores. An assignment of bands in resonance Raman spectra was done to monitor the structure and properties of the mesoporous silica material with regard to the methods of synthesis used in this study. It was shown, that Raman scattering can be useful for probing of functionalizations efficiency of mesoporous silica. On the base of the resonance investigation: Raman and EPR spectroscopy, distribution of the functional groups inside pores can be determined. In the present article the Raman spectroscopy is treat as a complementary research to EPR investigation. It was shown that a clustering of the active groups alter significantly the resonance Raman spectra through broadening and shifts of the corresponding bands in comparison with separated molecules. Results obtained from the analysis of the resonance Raman spectra indicate significant differences between the samples prepared by the two procedures. The discussion of the Raman results was referred to EPR results, and on the base of this authors concluded about correct achievement of the functionalization.

Porous Silica-Based Optoelectronic Elements as Interconnection Weights in Molecular Neural Networks

The paper describes a unique approach to optoelectronic elements application in artificial intelligence. Previously we considered molecular neural networks on the base of the functional porous silica thin films. But, for the successful molecular neural network design, we need efficient connections among them. Therefore we are presenting a material with tuneable non-linear optical (NLO) properties to be used for the optical signal transfer. The idea is briefly described and then followed by an experimental part to validate its feasibility. Promising results show that it is possible to design and synthesize the material with tuneable NLO properties.

Porous Silica Templated Nanomaterials for Artificial Intelligence and IT Technologies

This paper focuses on two types of novel nanomaterials based on ordered mesoporous silica designed for applications in artificial intelligence and IT technologies: molecular neural network and super dense magnetic memories. There’s no doubt that electronics needs new solutions for the further development. Nanotechnology comes here with the help. Especially nanostructured functional materials can help solve the problem of miniaturization.