Department of Synthesis and Characterization of Polymers

The aim of the department is to cover completely the expertise in synthesis of polymers using various polymerization techniques including free radical, reversible-deactivation radical and anionic polymerizations. The second object of synthesis represents preparation, spectral characterization and mainly utilization of different fluorescence probes for characterization of polymer microstructure and for polymerization study mechanism. Modification of polymers by grafting, crosslinking and functionalizations and preparation of polymeric and inorganic nanoparticles and hybrids represents another part of synthetic direction. Prepared as well as comercial polymers are characterised by spectral methods (UV-VIS, FTIR, Fluorescence and Raman spectroscopy), thermal analysis (DSC, TGA, chemiluminescence, thermal and photo stability, flammability) and their molar characteristics by advanced HPLC techniques. Electron spin resonance (ESR) and positron annihilation lifetime spectroscopy (PALS) techniques are used for the microscopic structural-dynamic characterization of various pure and composed organic materials.

Research Topics:

1. Study and development of reversible-deactivation radical polymerizations and synthesis of functional polymers
2. Inorganic and carbon (nano)particles and hybrids
3. Polymeric (nano)particles, (hydro)gels and (nano)fibres
4. Synthesis and properties of photoactive compounds
5. Synthesis of polymers and polymeric materials from renewable monomers
6. Degradation, stabilization and flammability of polymers
7. Liquid chromatography research for effective separation of macromolecules
8. Structure and physico - chemical properties of polymers

2. Inorganic and carbon (nano)particles and hybrids

Smart biodecorated hybrid nanoparticles

The hybrid nano(bio)materials, namely quatum dots-, carbon nanotubes- and noble metal nanoparticles- based nanomaterials that have been recently explored, are used for sensing, imaging and therapeutic applications. picture

The enhanced cellular drug delivery to cancer cell lines via nanoconjugates revealed that PEG-covered gold nanoparticles, quantum dots, carbon nanotubes, are an effective tool for transporting and delivering biodecorated nanomaterials-bassed drugs. Biodecorated nanoparticles provide opportunities for designing various types of therapeutics with novel properties that are not possible to obtain with traditional therapeutics. picture
Schematic representation of formation of different gold nanoparticle probes. 1) Thiolated or disulfide modified ligands, 2) electrostatic interaction, 3) antibody-antigen associations and 4) streptavidin-biotin binding.

Related recent publications:

  • I.Capek, „DNA Engineered Noble Metal Nanoparticles: Fundementals and State-of-the-Art of Nanotechnology“, Wiley&Sons, Scrivener Publishing USA, Ed. I. Capek, 2015, 1-656 p.
  • I. Capek, „On Biodecorated Gold Nanoparticles Distributed within Tissues and Cells“, J. Nanomed. Res., Vol. 2 (2), Art.No. 00021, p. 1-10 (2015), DOI: 10.15406/jnmr.2015.02.00021
  • I. Capek, „Plasmonic Nanoparticles and Their Conjugates: Preparation, Optical Properties and Antimicrobial Activity“, J. Nanotech. Mater. Sci., Vol. 2 (1), p. 1-18 (2015).

Polymeric hybrids prepared using surface initiated polymerizations and/or grafting onto methods

Good dispersion and homogeneous distribution of nanofillers in polymer matrices is the key factor for effective transfer of nanofiller properties to final polymer material at low nanofiller concentrations. Modification of CNT using surface initiated ATRP is performed in order to improve CNTs dispersion and/or obtain preferential interactions or even preferential localization of CNTs in one phase of triblock thermoplastic elastomers, such as polystyrene-block-polyisoprene-block-polystyrene or poly(methyl methacrylate)-block-poly(butyl acrylate)-block-poly(methyl methacrylate) (PMMA-b-PBA-b-PMMA).

The specific interactions between the filler and individual blocks are investigated by DMA and characterized also based on calculated activation energy of glass transitions of the individual phases. Surface modification of nanofillers in one step during synthesis of polymer matrix can provide composites with well dispersed nanofillers. CNT-g-PBA-b-PMMA / PMMA-b-PBA-b-PMMA nanocomposite prepared using this method showed significant improvement of viscoelastic properties in the wide range of temperatures (from 0 to 240 °C) and high photoactuation ability with fast and reversible response.

Reduction of graphene oxide by tertiary amine in situ during atom transfer radical polymerization
Synthesis of conductive hybrids and/or composites is investigated by in situ reduction of graphene oxide (GO) during (surface initiated) atom transfer radical polymerization. It was proven that tertiary amines, commonly used in ATRP as a ligands in the copper catalyst system, are responsible for the reduction of GO during ATRP and no further reducing agent is needed. Thus, the tertiary amine is involved in two separate competitive processes – catalysis of the polymerization and GO reduction. Using sufficient amount of a ligand is crucial to perform ATRP in the presence of GO. Using excess tertiary amine, compared to copper catalyst, can increase both the rate of polymerization and the reduction of GO. The final conductivity of the reduced GO hybrids can be finely tuned by adjusting the experimental conditions, as was successfully applied in preparation of reduced GO-based electromagnetic suspensions.

Scheme of surface modification of carbonyl iron by surface initiated ATRP of glycidyl methacrylate
Surface initiated polymerizations are used for modification of inorganic (nano)particles for improvement of their stability in solutions for various applications, such as electro or magnetorheology.

Schematic illustration of iron nanoparticles coated with phosphonate containing polybutylacrylate prepared via ATRP.
Design of iron oxide nanoparticles grafted with polymeric surfactants for chemiresistors. In this research, iron oxide nanoparticles (IONPs) were synthesized by thermal decomposition and reduction of Fe(acac)3, in the presence of oleic acid and oleylamine as surfactants. Several alkyl halide initiators containing either dopamine or phosphonic acid funcionalities were prepared and used for preparation of well-defined polymers using atom transfer radical polymerization (ATRP). The effect of polymer structure (polybutylacrylate and polystyrene) and the length of polymer chain of synthesized polymeric surfactants were investigated. In addition to polymer attachment onto the IONPs surface by “grafting onto” approach, also “grafting from” approach was applied. Well dispersed nanoparticles coated with various polymeric surfactants were purified by repeated cycles of redispersion/centrifugation. Dynamic light scattering analysis (DLS) was used to evaluate the size distribution profile and size of obtained nanoparticles. The diameter of oleyl-chains coated iron nanoparticles increased from 8 nm up to 15 – 20 nm after coating with polymer chains, depending on the nature and the molar mass of the employed polymeric surfactant.

Related recent publications: