Tomasz Makowski

Macroscopically aligned films of discotic phthalocyanine by zone casting

This work describes a room temperature liquid crystalline phthalocyanine processed by using zone casting. Highly oriented films that were uniform over several square centimeters were obtained on glass support from a mixed solvent (1:1 mixture of toluene and ethylene chloride) solution. A columnar planar alignment of Colr in the film layers has been determined by optical polarized microscopy, ultraviolet–visible absorption, atomic force microscopy and x-ray diffraction studies. The films consist of uniaxially oriented ribbon-like structures with molecular columns perpendicular to the solidification direction. The pronounced alignment makes these thin films promising for application in optoelectronic devices.

Superhydrophobic properties of cotton woven fabrics with conducting 3D networks of multiwall carbon nanotubes, MWCNTs

This article presents the findings concerning the preparation and properties of cotton woven fabrics with a conductive network made of multiwall carbon nanotubes deposited on the fiber surface by the padding method. The next stage of treatment consisted of imparting superhydrophobic properties to the fabrics in solution with methyltrichlorosilane (MTCS) in a waterless medium. The tests performed show that the state of surface and water content in cotton fibers exerts a significant influence on the hydrophobic properties of the analyzed samples. In order to explain the differences in hydrophobic properties, the morphology of the cotton fabric surface was examined using samples with various water contents. The formation mechanism of MTCS coatings on cotton fabric has been proposed.

Electrochemical deposition of silver nanoparticle and polymerization of pyrrole on fabrics via conducting multiwall carbon nanotubes

The paper presents results of tests on the possibility of utilising fabric with a deposited spatial network of multiwall carbon nanotubes (MWCNTs) as electrodes in processes of their functionalization by electrochemical methods enabling deposition of metal nanoparticles, as well as—by electropolymerization—of conductive polymer nanocoatings. Cyclic voltammetry was employed in the testing, which was used to functionalise various types of fabrics covered with a MWCNT spatial network by depositing silver nanoparticles and polypyrrole (PPy) nanocoating, conferring bioactive properties and significantly increased specific capacity, respectively, to the layered hybrid textile materials acquired this way.

Nanostructured surfaces by supramolecular self-assembly of linear oligosilsesquioxanes with biocompatible side groups

Summary Linear oligomeric silsesquioxanes with polar side moieties (e.g., carboxylic groups and derivatives of N-acetylcysteine, cysteine hydrochloride or glutathione) can form specific, self-assembled nanostructures when deposited on mica by dip coating. The mechanism of adsorption is based on molecule-to-substrate interactions between carboxylic groups and mica. Intermolecular cross-linking by hydrogen bonds was also observed due to the donor–acceptor character of the functional groups. The texture of supramolecular nanostructures formed by the studied materials on mica was analysed with atomic force microscopy and their specific surface energy was estimated by contact angle measurements. Significant differences in the surface roughness, thickness and the arrangement of macromolecules were noted depending on the kind of functional groups on the side chains. Specific changes in the morphology of the surface layer were observed when mica was primed with a monolayer of small organic compounds (e.g., N-acetylcysteine, citric acid, thioglycolic or acid). The adsorption of both silsesquioxane oligomers and organic primers was confirmed with attenuated total reflectance infrared spectroscopy. The observed physiochemical and textural variations in the adsorbed materials correlate with the differences in the chemical structure of the applied oligomers and primers.

Self-Assembly of Triblock Copolymers from Cyclic Esters as a Tool for Tuning Their Particle Morphology

This paper presents the effect of end groups, chain structure, and stereocomplexation on the microparticle and nanoparticle morphology and thermal properties of the supramolecular triblock copolyesters. Therefore, the series of the triblock copolymers composed of l,l- and d,d-lactide, trimethylene carbonate (TMC), and ε-caprolactone (CL) with isopropyl ( iPr) or 2-ureido-4-[1 H]-pyrimidinone (UPy) end groups at both chain ends were synthesized. In addition, these copolymers were intermoleculary stereocomplexed by polylactide (PLA) blocks with an opposite configuration of repeating units to promote their self-assembly in various organic solvents. The combination of two noncovalent interactions of the end groups and PLA enantiomeric chains leads to stronger interactions between macromolecules and allows for alteration of their segmental mobility. The simple tuning of the copolymer microstructure and functionality induced the self-assembly of macromolecules at liquid/liquid interfaces, which consequently leads to their phase separation in the form of particles with diameters ranging from 0.1 μm to 10 μm. This control is essential for their potential applications in the biomedical field, where biocompatible and well-defined microparticles and nanoparticles are highly desirable.

Bacterial cell killing properties of silver-loaded polysiloxane microspheres

Cross-linked polysiloxane microspheres containing a large number of SiOH groups were modified by introduction of organic thiol groups, which were further used for the functionalization of the microspheres with silver thiolate groups. The microspheres were characterized by 29Si MAS NMR, 13C MAS NMR, SEM, XPS and elemental analysis. They were tested as biocides against selected Gram-positive and Gram-negative bacteria strains and exhibited high bactericidal activity. Separately, linear polysiloxane polymers equipped with organothiol groups and loaded with silver were synthesized. Their antibacterial activity was compared with that of silver thiolate-functionalized microspheres. Different shape of particles and a different form of silver explained somewhat lower activity of polymers.

Spectroscopic characterization of the structural properties of quinoxalinophenanthrophenazine thin films

Thin films of 2,11-bis(1,1-dimethylethyl)-6,7,15,16-tetramethylquinoxalino[2′,3′:9,10]phenanthro[4,5-abc]phenazine (TQPP-Me) and its long chain alkoxy derivative 2,11-bis(1,1-dimethylethyl)-6,7,15,16-tetrakis(dodecyloxy)quinoxalino[2′,3′:9,10]phenanthro[4,5-abc]phenazine (TQPP-OC12) on silicon/native silica (Si/SiO2)native and fused silica substrates were analyzed in respect of their microstructural and anisotropic optical properties. The molecules, considered as candidates for organic electronic applications, have different solubilities, hence the fabrication of their solid layers was carried out by various methods. Anisotropy resulting from the alignment and shape of the organic molecules was induced by the choice of sedimentation method on inorganic substrates. TQPP-Me thin films were obtained by organic molecular beam deposition in ultra-high vacuum conditions while TQPP-OC12 layers were produced from solution by spin coating. The alignment and microstructure of TQPP-Me and TQPP-OC12 molecules in the formed films were studied by optical microscopy, atomic force microscopy, polarized infrared measurements in transmission and reflection modes, polarized UV-Vis absorption and fluorescence spectroscopy, and spectroscopic ellipsometry. Optical properties and morphology of both studied films exhibit different textures with strongly uniaxial anisotropy in both cases. The TQPP-Me vacuum-deposited molecules are arranged parallel to the surface while the cores of spin-coated TQPP-OC12 are cofacially packed and tilted with respect to the surface normal. Ellipsometric measurements were fitted with an isotropic model; however, the results do not exclude uniaxial ordering of the investigated samples.

Adsorption and covalent binding of fibrinogen as a method for probing the chemical composition of poly(styrene/α-tert-butoxy-ω-vinylbenzyl-polyglycidol) microsphere surfaces

We investigated the distribution of polyglycidol and polystyrene on the surface of poly(styrene/α-tert-butoxy-ω-vinylbenzyl-polyglycidol) microspheres (random distribution or segregated into hydrophilic and hydrophobic patches), using fibrinogen (Fb) as a macromolecular probe. The fibrinogen was adsorbed or covalently attached to the surface of the poly(styrene-co-α-tert-butoxy-ω-vinylbenzyl-polyglycidol) (P(S/PGLy)) microspheres. The P(S/PGLy) particles were prepared by emulsion copolymerization of styrene and α-tert-butoxy-ω-vinylbenzyl-polyglycidol (PGLy) macromonomer initiated with potassium persulfate. The polymerizations yielded P(S/PGLy) particles with various surface fractions of polyglycidol, depending on the amount of added macromonomer and the addition process. In some syntheses, the entire macromonomer amount was added once at the beginning of the polymerization, while in others, the macromonomer was added gradually after the formation of particle seeds from pure polystyrene. XPS studies revealed that the fraction of polyglycidol in the interfacial layer of the microspheres was larger when the entire amount of macromonomer was added at the beginning of the polymerization than when it was added after formation of the polystyrene seeds. Studies of fibrinogen adsorption provided the first evidence of segregation of the hydrophobic (polystyrene) and hydrophilic (polyglycidol) components at the surface of the composite P(S/PGLy) microspheres into patches. The hydrophobic patches are composed mainly of polystyrene. However, they also contain a small amount of polyglycidol chains, making the adsorption of fibrinogen weaker than the adsorption onto the pure polystyrene. Studies of covalent immobilization of fibrinogen on the microspheres via 1,3,5-trichlorotriazine confirmed these findings.