Papers by Daniel Gromadzki
Polymer, May 1, 2009
The effect of polydispersity on dilute solution properties and microphase separation of polydispe... more The effect of polydispersity on dilute solution properties and microphase separation of polydisperse high-molecular-weight (M w > 10 5 g mol À1 ) polystyrene-block-poly(styrene-co-acrylonitrile) diblock copolymers, PS-block-P(S-co-AN), was studied in this work. For experiments, a series of diblock copolymers with variable weight fractions of acrylonitrile units (w AN ¼ 0.08-0.29) and length of block P(S-co-AN) was synthesized using nitroxide-mediated radical polymerization (NMP) technique, namely, by chain extension of nitroxide-terminated polystyrene (PS-TEMPO). According to light scattering and viscometry measurements in dilute tetrahydrofuran (THF) solutions the studied diblock copolymers assumed random coil conformation with the values of characteristic structure factor R g /R h ¼ 1.50-1.76. It was found that polydisperse diblock copolymers being in strong segregation limit (SSL) self-assembled into microphase-separated ordered morphologies at ordinary temperature. The long periods of lamellar microdomains were larger compared to theoretical predictions for hypothetical monodisperse diblock copolymers. It was demonstrated by means of SAXS and TEM that a transition from a lamellar (LAM) to irregular face-centered-cubic (FCC) morphology occurred with increasing volume fraction of P(S-co-AN) block.
e-Polymers, 2012
Anionic comb polyelectrolytes containing 2-acrylamido-2-methyl-
Polymer, 2009
The effect of polydispersity on dilute solution properties and microphase separation of polydispe... more The effect of polydispersity on dilute solution properties and microphase separation of polydisperse high-molecular-weight (M w > 10 5 g mol À1 ) polystyrene-block-poly(styrene-co-acrylonitrile) diblock copolymers, PS-block-P(S-co-AN), was studied in this work. For experiments, a series of diblock copolymers with variable weight fractions of acrylonitrile units (w AN ¼ 0.08-0.29) and length of block P(S-co-AN) was synthesized using nitroxide-mediated radical polymerization (NMP) technique, namely, by chain extension of nitroxide-terminated polystyrene (PS-TEMPO). According to light scattering and viscometry measurements in dilute tetrahydrofuran (THF) solutions the studied diblock copolymers assumed random coil conformation with the values of characteristic structure factor R g /R h ¼ 1.50-1.76. It was found that polydisperse diblock copolymers being in strong segregation limit (SSL) self-assembled into microphase-separated ordered morphologies at ordinary temperature. The long periods of lamellar microdomains were larger compared to theoretical predictions for hypothetical monodisperse diblock copolymers. It was demonstrated by means of SAXS and TEM that a transition from a lamellar (LAM) to irregular face-centered-cubic (FCC) morphology occurred with increasing volume fraction of P(S-co-AN) block.
Polymer, 2010
Randomly branched (arborescent) poly(sodium 2-acrylamido-2-methyl-N-propanesulfonates) (NaPAMPS) ... more Randomly branched (arborescent) poly(sodium 2-acrylamido-2-methyl-N-propanesulfonates) (NaPAMPS) were synthesized via self-condensing vinyl polymerization using activators generated by electron transfer atom transfer radical polymerization (AGET ATRP). The controlled self-condensing AGET ATRP of NaAMPS was realized in the presence of 2-(2-bromopropionyloxy)ethyl acrylate (BPEA) as a branching monomer (inimer) in water/pyridine (35e50% of Py) mixed solvents. The content of BPEA in the reaction feed was varied from 10 to 30 wt% allowing the synthesis of NaPAMPS with different degree of branching. SEC determined molecular weight of the prepared NaPAMPS was M w ¼ 94 000e120 000 g/mol, and the accompanying polydispersity index PDI ranged from 1.84 to 2.47. The definite evidence of highly branched structure of NaPAMPS was provided by the dependence of radius of gyration R g on weight-average molecular weight M w with characteristic slope a ¼ 0.38e0.42, and by small-angle X-ray scattering (SAXS) analysis. Molecular parameters, conformation and dynamics of the branched NaPAMPS in dilute salt-free solutions and in the presence of a salt were elucidated by static and dynamic light scattering and SAXS.
European Polymer Journal, 2010
Loosely grafted amphiphilic molecular brushes consisting of a hydrophobic polystyrene backbone an... more Loosely grafted amphiphilic molecular brushes consisting of a hydrophobic polystyrene backbone and hydrophilic poly(ethylene glycol) monomethyl ether (MPEG) side chains, PS-MPEG, were synthesized by a novel two step method. In the first step, well-defined linear poly(p-chloromethylstyrene) PCMS with the degree of polymerization DP % 200 and polydispersity index, M w /M n = 1.4 was prepared by bulk nitroxide (TEMPO)-mediated radical polymerization (NMP). In the second step, pendant p-chloromethyl units were coupled with activated chains of poly(ethylene glycol) monomethyl ether (MPEG) during the course of the Williamson etherification reaction. Using MPEG with M n = 1100 g/mol over 50% repeating units on PCMS underwent nucleophilic substitution yielding a densely grafted brush with theoretical molecular weight M n,th % 123,000 g/mol. The molecular brush PS-MPEG assumed conformation of a stiff cylinder in both dilute toluene (non-selective good solvent for PS backbone and MPEG grafts) and water (selective for MPEG grafts) solutions as determined by small-angle neutron scattering (SANS) and small-angle X-ray scattering (SAXS). The contour length L = 570 Å and L = 694 Å obtained by fitting the scattering data using model of Sharp-Bloomfield, Pedersen-Schurtenberger and Kholodenko worm revealed dimensions corresponding to theoretically estimated size of a single molecular brush. It was found that PS-MPEG molecular brush in dilute aqueous solutions exhibited lower critical solution temperature (LCST) in the physiological range.
European Polymer Journal, 2006
The morphological behavior of partially sulfonated polystyrene-block-poly(ethylene-alt-propylene)... more The morphological behavior of partially sulfonated polystyrene-block-poly(ethylene-alt-propylene) (PS-PEP) membranes cast from tetrahydrofuran (THF) solutions were investigated by small-angle X-ray scattering (SAXS) and atomic force microscopy (AFM). The uptakes of methanol and water increase as the sulfonation degree increases, the methanol uptake being overwhelmingly greater than the water uptake. The conductivity increases almost exponentially with increasing sulfonation degree of polystyrene units. Clusters of sulfonated units that are formed in the solution used for casting membranes persist in the solid state after evaporation. In contact with water, swelling of the membranes proceeds predominantly in these clusters. The original lamellar morphology of the diblock copolymer is progressively deformed with increasing degree of sulfonation by the presence of the clusters containing ion-rich sequences of sulfonated polystyrene blocks.
European Polymer Journal, 2008
Well-defined polystyrene-block-poly(styrene-co-acrylonitrile) PS-block-P(S-co-AN) and poly(styren... more Well-defined polystyrene-block-poly(styrene-co-acrylonitrile) PS-block-P(S-co-AN) and poly(styrene-co-acrylonitrile-co-5-vinyltetrazole) PS-block-P(S-co-AN-co-5VT) block copolymers with various content of acrylonitrile units in the statistical block were synthesized by nitroxide mediated radical polymerization (NMRP) and post-functionalized using efficient “click” chemistry process. In the second step, acrylonitrile units were successfully modified using 1,3-dipolar cycloaddition (“click” chemistry) type polymer analogue reaction. The original pristine diblock copolymers can be molecularly dissolved
European Polymer Journal, 2010
Conventional free-radical and RAFT copolymerization of poly(ethylene oxide) substituent containin... more Conventional free-radical and RAFT copolymerization of poly(ethylene oxide) substituent containing methacrylate macromonomers, PEO 5 MEMA and PEO 45 MEMA, was studied by the use of 1 H NMR spectroscopy for an analysis of residual monomers. From the monomer consumption curves, several parameters including monomer conversion, instantaneous copolymer composition and reactivity ratios of the monomers were evaluated. Reactivity ratios of PEO 5 MEMA and MAA estimated by non-linear approach of error-in-variables model and presented as joint confidence regions were constant during conventional free-radical and RAFT copolymerizations of the above monomers but were slightly affected by the RAFT process. Reactivity ratio of PEO 45 MEMA was found to be lower than that of PEO 5 MEMA and varied during copolymerization: increased with conversion in conventional free-radical copolymerization and slightly (without confidence) decreased in the RAFT process. RAFT copolymerization of PEO 45 MEMA and MAA enabled to synthesize comb copolymers with low composition distribution and more homogeneous distribution of PEO side chains along the mainchain. Under copolymerization with MAA, PEO 45 MEMA behaved like typical macromonomer with appropriate steric hindrance while the behavior of PEO 5 MEMA was similar to that of a low-molecular methacrylate.
European Polymer Journal, 2008
Comb copolymers consisting of polystyrene backbone and poly(tert-butyl (meth)acrylate) side chain... more Comb copolymers consisting of polystyrene backbone and poly(tert-butyl (meth)acrylate) side chains were synthesized by combination of nitroxide (TEMPO)-mediated polymerization (NMP) and photoinduced grafting from macro-iniferters. First, poly(chloromethylstyrene), PCMS, with the degree of polymerization DPn¯≈200 and two random poly(styrene-co-chloromethylstyrene) copolymers, P(S-co-CMS), with similar DPn¯≈75 but different content (8 and 14mol%) of CMS units, were synthesized by NMP. In the second step
Reviews in Environmental Science and Bio/Technology, 2010
Nanostructured amphiphilic block copolymers, graft copolymers, polymeric thermally responsive mol... more Nanostructured amphiphilic block copolymers, graft copolymers, polymeric thermally responsive molecular brushes and polymer stars are only few examples of macromolecular architectures accessible either via controlled/living radical polymerization (CLRP) techniques or the combination of CLRP mechanisms with efficient post-polymerization routes including click chemistry. Precise control over the composition, molecular weight and functionalities is a prerequisite for soft polymeric materials to selforganize into ordered morphologies. This contribution describes novel orthogonal chemical routes for the synthesis of macromolecular architectures and selfassembly of functional soft polymeric materials. Emerging potential applications of well-defined block and graft copolymers are outlined as well.
European Polymer Journal, 2009
ABSTRACT We report on solution properties of lightly grafted copolymers composed of polystyrene (... more ABSTRACT We report on solution properties of lightly grafted copolymers composed of polystyrene (PS) backbone (degree of polymerization of PS backbone, Nb=95) and variable length of poly(tert-butyl methacrylate) P(tBuMA) side chains (degree of polymerization of side chains, Nsc=14–222) at fixed number of grafting sites n=11 and polydispersity index (Mw/Mn) ranging from 1.05 to 2.63. Synthesis of these graft copolymers is based on a novel synthetic route [Gromadzki D, Makuška R, Netopilík M, Holler P, Lokaj J, Janata M, et al. Eur Polym J 2008;44:59–71] involving two independent controlled/“living” polymerization mechanisms, namely nitroxide-mediated radical polymerization (NMP) for the synthesis of the backbone and photoinduced “grafting from”iniferter process for building of P(tBuMA) branches. The viscosity-related contraction factors g′1 confirmed high degree of branching of the studied graft copolymers. Dilute solutions of graft copolymers in non-selective solvent (THF), examined by dynamic light scattering (DLS), small-angle X-ray scattering (SAXS) and viscometry, revealed a transition from comb-like conformation through wormlike-star to a microgel architecture under increasing number of monomeric units in side chains. These data were further supported by the structure factors Rη/Rh and Rg/Rh obtained by independent measurements and extrapolated to infinite dilution. Persistence lengths of the samples exhibiting comb-like topology were larger compared to linear polystyrene backbone and P(tBuMA) side chains in THF suggesting stiffening of the main chain with increasing size of the attached side chains. Unimolecular micelles were detected by DLS and SAXS in solvent selective for grafts, tert-amyl alcohol.
2 Institute of Macromolecular Chemistry, Academy of Sciences of the Czech Republic, Heyrovsky Sq.... more 2 Institute of Macromolecular Chemistry, Academy of Sciences of the Czech Republic, Heyrovsky Sq. 2, 162 06 Prague 6, Czech Republic Reversible addition-fragmentation chain transfer (RAFT) polymerization of lauryl methacrylate (LMA) in the presence of S-methoxycarbonyl phenylmethyl dithiobenzoate (MCPDB) as a RAFT chain transfer agent (CTA) and subsequent RAFT polymerization of poly(ethylene oxide) monomethyl ether methacrylate (PEO5MEMA or PEO45MEMA) was done with the aim to prepare amphiphilic diblock copolymer brushes of controlled structure. The molecular weight of PLMA and PLMA-b-PPEO5MEMA copolymers was evaluated by several methods including SEC calibrated using polystyrene standards, and end-group analysis by 1H NMR and UV-Vis. The kinetics of LMA polymerization was followed by 1H NMR spectroscopy by comparing the signals attributed to the monomer and corresponding monomeric units in PLMA. RAFT polymerization of LMA at the ratio [MCPDP] : [AIBN] = 4 demonstrated the “living” ...
Fibres & Textiles in Eastern Europe, 2008
Aliphatic copolyesters of succinic acid (SA) and dimerized fatty acid (saturated dilinoleic acid ... more Aliphatic copolyesters of succinic acid (SA) and dimerized fatty acid (saturated dilinoleic acid (DLA)) were synthesized via direct copolycondensation in the presence of 1,4-butane- diol. The thermal and mechanical properties of these copolymers were investigated as a function of the hard/soft segments' ratio. The results of small-angle X-ray scattering (SAXS) investigations revealed that the characteristic d spacing of the copolyester supermolecular structure increases from 7 nm to 14 nm with increasing content of soft segments, DLA. It was found that the crystalline phase content determined by WAXS increases from 22 to 66% and was found to increase with increasing content in polybutylene succinate (PBS) se- quences and increasing polybutylene succinate (PBS) sequence length. Also, it was shown that the synthesized polymers are susceptible to biodegradation and that the highest mass losses occurred for copolymers of lower crystallinity.
Processes
Nitroxide-mediated polymerization using the succinimidyl ester functional unimolecular alkoxyamin... more Nitroxide-mediated polymerization using the succinimidyl ester functional unimolecular alkoxyamine initiator (NHS-BlocBuilder) was used to first copolymerize tert-butyl methacrylate/ 2-vinylpyridine (tBMA/2VP) with low dispersity (Đ = 1.30-1.41) and controlled growth (linear number average molecular M n versus conversion, M n = 3.8-10.4 kg•mol −1) across a wide composition of ranges (initial mol fraction 2VP, f 2VP,0 = 0.10-0.90). The resulting statistical copolymers were first de-protected to give statistical polyampholytic copolymers comprised of methacrylic acid/2VP (MAA/2VP) units. These copolymers exhibited tunable water-solubility due to the different pKas of the acidic MAA and basic 2VP units; being soluble at very low pH < 3 and high pH > 8. One of the tBMA/2VP copolymers was used as a macroinitiator for a 4-acryloylmorpholine/4-acryloylpiperidine (4AM/4AP) mixture, to provide a second block with thermo-responsive behavior with tunable cloud point temperature (CPT), depending on the ratio of 4AM:4AP. Dynamic light scattering of the block copolymer at various pHs (3, 7 and 10) as a function of temperature indicated a rapid increase in particle size >2000 nm at 22-27 • C, corresponding to the 4AM/4AP segment's thermos-responsiveness followed by a leveling in particle size to about 500 nm at higher temperatures.
International Journal of Polymeric Materials and Polymeric Biomaterials
ABSTRACT Multifunctional nanocarriers are gaining increasing research interest as polymeric platf... more ABSTRACT Multifunctional nanocarriers are gaining increasing research interest as polymeric platforms for targeted drug delivery in cancer therapy and diagnosis. In this work, preparation and characterization of surfactant-free polyester nanoparticles (NPs) from a bio-based poly(butylene sebacate-co-butylene dilinoleate)s, poly(butylene sebacate) (PBSE)/poly(butylene dilinoleate) (PBDL), using nanoprecipitation, is reported. The polymeric nanoparticles (sizes narrowly distributed in a range less than 100 nm) were loaded with curcumin (CURC) with an encapsulation efficiency of 98% and drug loading (DL) content of 5–10% wtdrug/wtpolymer. The CURC-loaded nanoparticles were efficiently coated with a novel poly(sulfobetaine)-type zwitterionic polymer synthesized by nitroxide-mediated polymerization and postpolymerization functionalization step. Free and CURC formulated into noncoated and poly(sulfobetaine)-type zwitterionic polymer-coated nanoparticles were further investigated for cytotoxicity and antioxidant activity in a panel of human cell lines and rat liver microsomes, respectively. Formulated into coated NPs, CURC has superior cytotoxic and antioxidant activity versus the free drug and CURC incorporated in noncoated NPs. In addition, cell viability experiments of nonloaded nanoparticles, both coated and noncoated, demonstrated that developed nanoparticles are nontoxic, making them potentially suitable candidates for systemic passive targeting in cancer therapy, namely for treatment of solid tumors exhibiting high tumor accumulation of NPs due to enhanced permeability and retention effect. Polyzwitterion-coated nanoparticles exhibited slower drug release compared with the noncoated ones (half as much after 24 h) presumably due to the presence of the polymer shell around nanoparticles associated with a wider diffusion layer around the particles. GRAPHICAL ABSTRACT
Carbon, 2017
Graphene possesses unique features that make it attractive for nanotechnology. Functional devices... more Graphene possesses unique features that make it attractive for nanotechnology. Functional devices often require combination of several materials with specific functions, and graphenepolymer composites are one of them. Herein, we report on the preparation of PEDOT:Graphene bilayers by in situ polymerization of EDOT on covalently functionalized graphene. The polymerization proceeds exclusively on the grafted graphene, and patterned structures with high spatial resolution down to 3 μm could have been prepared. The composite exhibits enhanced efficiency of electrochemical doping compared to pristine graphene, unsymmetrical transport characteristic with very good hole-transporting properties and efficient electronic communication between the two materials.
Cancer Research, 2015
Graphene(GO)/Pectin/NaCl gel-patch was prepared and evaluated for its bio-sensing. Physical and c... more Graphene(GO)/Pectin/NaCl gel-patch was prepared and evaluated for its bio-sensing. Physical and chemical analyses were carried out to focus the properties of new bio-sensing gel. Afterwards paclitaxel was loaded in the graphene based gel and drug delivery was carried out for dermal delivery, using a biomembrane, a fish swim-bladder in vitro. Kinetic studies were evaluated for feasibility as dermal delivery. Getting information from the kinetic parameters, paclitaxel was delivered to the melanoma cell lines from the gel and cell apoptosis was performed by trypan blue staining. FTIR studies were performed to evaluate the IR-signal transmission between the GO/Pectin/NaCl blend gel and Pectin/NaCl gel. And the same signal was evaluated from that of paclitaxel loaded GO/Pectin/NaCl treated melanoma cells and normal endothelial cells. All our data suggests that GO/Pectin/NaCl blend gel might be a future diagnostic as well as curable anticancer carrier for local cancer therapy. Note: This abstract was not presented at the meeting. Citation Format: Sharif M. Shaheen, Daniel Gromadzki, Amor Abdelkader, Stanislav Rangelov. Graphene/Pectin-NaCl based gel-biosensor for tracing skin cancer and delivery of anticancer drug paclitaxel. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 4535. doi:10.1158/1538-7445.AM2015-4535
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Papers by Daniel Gromadzki