Abstracts

 

Dimitra Stavroulaki1, Foteini Arfara1, Panagiotis Christakopoulos1, Panagiota Fragouli2, Hermis Iatrou1

1 INDUSTRIAL CHEMISTRY LABORATORY, DEPARTMENT OF CHEMISTRY, NATIONAL AND KAPODISTRIAN UNIVERSITY OF ATHENS
2 DEPARTMENT OF TEXTILE ENGINEERING, PIRAEUS UNIVERSITY OF APPLIED SCIENCES

In recent decades, synthetic polypeptides have shown promise for many bio-applications due to their biodegradability, biocompatibility, and their native secondary structures. Their ability to respond to external stimuli, such as pH, light, redox, temperature and enzymes renders them very popular as novel drug and gene delivery systems. Herein we present the synthesis of a series of hybrid polypeptide copolymers based on poly(L-Histidine), poly(L-Alanine) and poly(L-Cysteine). The synthesis of the polymers was achieved through a ring-opening polymerization (ROP) process of the corresponding N-carboxy anhydrides, using an amine end-functionalized poly(ethylene oxide) (m-PEO-NH 2 ) macroinitiator. High-vacuum techniques were used for the synthesis of N-carboxy anhydrides of a-amino acids and for the isolation of well-defined polymers, ensuring high purity of the system. The successful synthesis of the polymers was confirmed by SEC, 1 H-NMR and FT-IR. In addition, the relationship between the secondary structure of the polypeptides and pH and temperature was studied using circular dichroism (CD). Finally, dynamic light scattering (DLS) and static light scattering (SLS) were employed in order to investigate the ability of the polypeptides to self-assemble into micelles. The synthesized polymers could self-assemble in aqueous media and form micelle-like nanostructures. The outer hydrophilic corona of the nanostructures was comprised of poly(ethylene oxide) chains, while the hydrophobic core was based on either poly(L-Histidine) and poly(L-Alanine) or poly(L-Cysteine), polypeptides, which exhibit pH, thermo and redox- responsiveness, respectively. The ultimate goal was to create “stimuli-responsive” polypeptides, for targeted and controlled drug release applications to cancer cells.

NIKOLETTA ROKA1, Eleftheria Mitsoni1, Olga Kokkorogianni1, Marinos Pitsikalis1

1 INDUSTRIAL CHEMISTRY LABORATORY, DEPARTMENT OF CHEMISTRY, NATIONAL AND KAPODISTRIAN UNIVERSITY OF ATHENS

Poly(N-Vinylpyrrolidone) (PNVP) is an attractive polymer, industrially important due to its biocompatibility and biodegradability, low toxicity, high complexing ability and good film-forming characteristics. PNVP can be perfectly polymerized with Reversible Addition- Fragmentation chain Transfer (RAFT) polymerization. RAFT polymerization is a well-established method for providing living characteristics to conventional radical polymerization. The advantages of RAFT include the facile processes under routine experimental conditions coupled with the tolerance of unprotected functionality in monomer and solvent. In this work, the synthesis and characterization of N-vinylpyrrolidone statistical and block copolymers with various methacrylates such as benzyl methacrylate, 2-(dimethylamino)ethyl methacrylate, stearyl methacrylate and hexyl methacrylate is reported. Eventhought N-vinylpyrrolidone is a less active monomer compared to the methacrylates, both of them are successfully polymerized with the same Chain Transfer Agent (CTA). Actually, they have been used three different xanthates as CTAs: [(O-ethylxanthyl)methyl]benzene, [1-(O-ethylxanthyl)ethyl] benzene and O-ethyl S-(phthalimidylmethyl) xanthate. The reactivity ratios were estimated using the Fineman-Ross, inverted Fineman-Ross, Kelen-Tüdos, and extended Kelen-Tüdos graphical methods, along with the computer program COPOINT. All the methods indicate that the reactivity ratio of the methacrylate is much greater than that of N-vinylpyrrolidone , thus, the statistical copolymers are in fact pseudo-diblocks. The glass-transition temperature values of the copolymers were measured by Differential Scanning Calorimetry. Furthermore, the thermal degradation of the copolymers was investigated, compared with the respective homopolymers, by Thermogravimetric Analysis, within the framework of the Ozawa-Flynn-Wall and Kissinger methodologies. The block copolymers were synthesized by sequential addition of monomers. The synthesis was monitored by SEC and NMR.

Stavros Zouganelis1, Ioannis Goulas2, Marinos Pitsikalis2

1 INDUSTRIAL CHEMISTRY LABORATORY, DEPARTMENT OF CHEMISTRY, NATIONAL & KAPODISTRIAN UNIVERSITY OF ATHENS, PANEPISTIMIOPOLIS ZOGRAFOU, 15 771 ATHENS, GREECE
2 INDUSTRIAL CHEMISTRY LABORATORY, DEPARTMENT OF CHEMISTRY, NATIONAL AND KAPODISTRIAN UNIVERSITY OF ATHENS

Poly(vinyl ethers) are a class of polymers with a wide variety of applications, such as adhesives, surface coatings and chemical processing. Among these polymers poly(2-chloroethyl vinyl ether) is a very useful intermediate product, since the chlorine atom can be substituted by other groups, thus offering the possibility to prepare functionalized and more complex architectures. Poly( ε -caprolactone) and poly(L-lactide) are highly compatible polymers with various industrial uses, including packaging, films and fibers. In this work, butyl vinyl ether and 2-chloroethyl vinyl ether were copolymerized using an activated cationic zirconocene complex as an initiator. The chlorine atoms of the resulting polymers were then substituted by azide groups after reaction with sodium azide. Poly( ε -caprolactone) and poly(L-Lactide) were synthesized using ring opening polymerization employing propargyl alcohol and stannous octate as the initiating system. The poly(vinyl ether) polymers and the poly(lactones) or poly(lactides) were consequently reacted through copper catalyzed click reaction, resulting in graft copolymers. SEC, IR and NMR were employed to monitor the reaction sequence and characterize the products. Finally, the thermal properties of these graft copolymers were studied with Differential Scanning Calorimetry (DSC) and Thermogravimetric Analysis (TGA) and were compared with the responding properties of the original polymers. This synthetic route offers a general approach for the synthesis of amphiphilic or amorphous-crystalline graft copolymers with unique solution and solid state properties.  

Harm-Anton Klok1

1

Polymer science provides a diverse toolbox to modify both synthetic and biological surfaces. The first part of this lecture will discuss the use of surface-initiated, controlled radical polymerization (SI-CRP) techniques for the preparation of thin, surface tethered polymer brushes. SI-CRP reactions possess a number of attractive features, such as the ability to prepare brushes (i) with precise control over chemical composition and film thickness; (ii) that present very high surface concentrations of functional groups; (iii) that conformally coat complex, 3D structured or porous substrates and which allows to (iv) tune the conformation of the surface grafted chains. This presentation will highlight the use of SI-CRP to generate polymer films with sensory or responsive properties as well as results from recent work, which shows that the conformation of surface grafted polymer chains also impacts their chemical reactivity, potentially opening avenues towards novel mechanically responsive surfaces. The second part of this talk will concentrate on biological surfaces and more specifically the membrane of living cells. Living cells are attractive carriers to mediate transport of drug-loaded polymer particles. The successful use of cells as carriers for polymers and polymer particles requires chemical approaches that allow to immobilize (and release) the polymer or particle payload from the cell surface, without compromising cell viability and function. This presentation will discuss various polymer cell surface modification strategies and compare these different approaches in terms of the possibilities they offer to modify cell surfaces as well as their impact on cell viability and function.

Spyridoula-Lida Bitsi1, Salvatore Constanzo2, Dimitris Vlassopoulos2, Anastasia Nika3, Margarita Chatzichristidi1, Marinos Pitsikalis3

1 INDUSTRIAL CHEMISTRY LABORATORY, DEPARTMENT OF CHEMISTRY, NATIONAL & KAPODISTRIAN UNIVERSITY OF ATHENS
2 INSTITUTE OF ELECTRONIC STRUCTURE AND LASER, FOUNDATION FOR RESEARCH AND TECHNOLOGY
3 INDUSTRIAL CHEMISTRY LABORATORY, DEPARTMENT OF CHEMISTRY, NATIONAL AND KAPODISTRIAN UNIVERSITY OF ATHENS

Three different series of very low molecular weight ω -functionalized homopolymers PS-OH and diblock copolymers PS-b-PI-OH and PI-b-PS-OH, where PS is polystyrene and PI is polyisoprene, were synthesized by living anionic polymerization techniques. Samples of different molecular weights, and/or compositions where obtained. Through the end-hydroxyl group the functional unit 2-ureido-4-pyrimidone (UPy) was introduced in each sample. The UPy-group is strongly dimerized in a self-complementary array of four cooperative hydrogen bonds. This new class of supramolecular, non-covalent polymers (in this case with hydrogen bonds) is promising as their properties can be manipulated upon changing the experimental conditions (temperature, solvent, shear forces and concentration). Size exclusion chromatography (SEC) and 1 H-NMR were carried out to verify the existence of these ω -functionalized polymers. Atomic force microscopy (AFM), dynamic light scattering (DLS) and viscometry were carried out and revealed that the above mentioned polymers, do not only form dimers, but also create different populations of nanostructures and networks. Other experimental techniques, such as thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and rheology, confirm the strong effect of the non-covalent bonds. The polar UPy-groups are responsible for this complex aggregation behavior in non polar solvents due to the formation of self-complementary hydrogen bonds. This behavior is even more pronounced due to the low molecular weight of the polymeric chains. As a result, the   ω - functionalized polymers can self assemble into large aggregates of a variety of sizes.

Εvdokia Οikonomou1, Nikolay Christov2, Galder Cristobal2, Claudie Bourgaux3, Laurent Heux4, Jean-Francois Berret1

1 LABORATOIRE MATIÈRE ET SYSTÈMES COMPLEXES, UMR 7057 CNRS UNIVERSITÉ DENIS DIDEROT PARIS-VII, BÂTIMENT CONDORCET, 10 RUE ALICE DOMON ET LÉONIE DUQUET, 75205 PARIS, FRANCE
2 SOLVAY SINGAPORE, 1 BIOPOLIS DR, AMNIOS, SINGAPORE 138622
3 INSTITUT GALIEN PARIS-SUD - UMR CNRS 8612, FACULTÉ DE PHARMACIE, UNIVERSITÉ PARIS-SUD XI, 92296 CHÂTENAY-MALABRY CEDEX, FRANCE
4 CENTRE DE RECHERCHES SUR LES MACROMOLÉCULES VÉGÉTALES, BP 53, 38041 GRENOBLE CEDEX 9, FRANCE

Nowadays there is a growing environmental concern about the household and personal care products due to their high content of surfactants derived by palm oil. Fabric softeners are formulations that contain ~10 wt. % double tailed surfactants primarily synthesized by palm oil chemical treatment. Here we propose the replacement of 50 % surfactant with natural polymers in particular cationic and hydroxyl propyl guar, without detrimental effects on their performance.   The surfactants in these formulations were found to be assembled into large distributed (0.1 – 1 µm) vesicles (Fig.1 a) . The effect of the polymers on the formulation properties was investigated by several physicochemical techniques . The reduction of surfactant is compensated by the guars as far as the rheological properties are concerned. In terms of performance, the role of the polymers and its chemical structure on the deposition of the vesicles, either on cellulose nanocrystals used as a model of cotton or on cotton fabrics was studied. Deposition studies such as scanning electron microscopy (Fig. 1b) and quartz crystal microbalance (QCM) indicate that guars enhance the surfactant deposition on cotton. This approach can thus be generalized to several formulations making polysaccharides a remarkable candidate for the development of eco-friendly household and personal care products.

ΘΕΟΔΩΡΟΣ ΣΕΝΤΟΥΚΑΣ1, ΣΤΕΡΓΙΟΣ ΠΙΣΠΑΣ2

1
2 ΕΘΝΙΚΟ ΙΔΡΥΜΑ ΕΡΕΥΝΩΝ - ΙΝΣΤΙΤΟΥΤΟ ΘΕΩΡΗΤΙΚΗΣ ΚΑΙ ΦΥΣΙΚΗΣ ΧΗΜΕΙΑΣ

Introduction Double thermoresponsive and pH responsive block copolymer systems have been at the center of attention due to their ability to self-assemble into discrete nanoscale formations at different temperatures and solution pH. In the present work, the synthesis and self-assembly properties in aqueous solutions of novel amphiphilic diblock copolymers composed of one hydrophilic, pH and temperature responsive poly(2-dimethylaminoethyl methacrylate) (PDMAEMA) block and one weakly hydrophobic, thermoresponsive poly(hydroxypropyl methacrylate) (PHPMA) block, are reported.  Methods The block copolymers were prepared by RAFT polymerization and were molecularly characterized by size exclusion chromatography, NMR and FTIR spectroscopies. The PDMAEMA blocks were quaternized with CH 3 I, leading to QPDMAEMA- b -PHPMA amphiphilic polyelectrolyte-neutral block copolymers. Self-assembly studies on aqueous solutions were conducted using three solubilization protocols at different pHs, followed by light scattering measurements. Results PDMAEMA- b -PHPMA copolymers exhibit thermoresponsive behavior at all pHs. Zeta potential and fluorescence spectroscopy experiments revealed a great dependence of the aggregate surface charge and the intraggregate polymeric chain assembly on the solvent-exchange protocol utilized and the pH of the aqueous solution. Direct solubilization in aqueous media led to swollen aggregates, while solvent exchange protocols led to more hydrophobic aggregates. Regarding the block polyelectrolyte analogs, the QPDMAEMA -b- PHPMA solutions presented also thermoresponsiveness, but to a lesser extent. Conclusions These studies shed light on ways for manipulating structure formation of doubly thermoresponsive and pH responsive diblock copolymers. Their nanostructured aggregates show potential for utilization in drug delivery and/or protein/peptide and gene delivery.

Christos Pantazidis1, Apostolos Avgeropoulos2, Georgios Sakellariou1

1 INDUSTRIAL CHEMISTRY LABORATORY, DEPARTMENT OF CHEMISTRY, NATIONAL & KAPODISTRIAN UNIVERSITY OF ATHENS, PANEPISTIMIOPOLIS ZOGRAFOU, 15 771 ATHENS, GREECE
2 DEPARTMENT OF MATERIALS SCIENCE AND ENGINEERING, UNIVERSITY OF IOANNINA, 45 110 IOANNINA, GREECE

Block copolymers composed of Polystyrene and Polydimethylsiloxane are well known for their nanolithography applications. Such materials are able to produce stable nanostructures through microphase separation.   The present research involves the synthesis and molecular characterization of linear diblock or triblock copolymers of the A- b -B or A- b -B- b -A type and miktoarm star copolymers of the Α ( Β ) 2,3 and Β ( Α ) 2,3 type, where Α : polystyrene (PS) and Β : polydimethylsiloxane (PDMS). A series of linear diblock and triblock copolymers with same total molecular weight and different chemical compositions was synthesized by anionic polymerization along with sequential monomer addition. Anionic polymerization along with chlorosilane chemistry were employed for the synthesis of all the miktoarm star copolymers. All samples were characterized via size exclusion chromatography (SEC) and proton nuclear magnetic resonance spectroscopy ( 1 H-NMR), while transmission electron microscopy (TEM) was employed for the morphological characterization of the samples.  Our main goal is to understand the effect of macromolecular architecture at the microphase separation of these samples and to create a complete phase diagram for the polystyrene/polydimethylsiloxane copolymers.  

NIKOS PATELIS1, MARTA CUTRANO2, DANIELE PARISI2, DIMITRIS VLASSOPOULOS2, GEORGE SAKELLARIOU1

1 INDUSTRIAL CHEMISTRY LABORATORY, DEPARTMENT OF CHEMISTRY, NATIONAL & KAPODISTRIAN UNIVERSITY OF ATHENS
2 INSTITUTE OF ELECTRONIC STRUCTURE AND LASER, FOUNDATION FOR RESEARCH AND TECHNOLOGY

Single-chain nanoparticles (SCNPs), unimolecular soft nano-objects consisting of individual polymer chains collapsed to a certain degree by means of intramolecular bonding, have attracted significant interest in recent years. Organic nanoparticles in a polymer matrix have been shown to influence both the mechanical and rheological properties of the nanocomposite material due to nanoscale effects. Herein, we present a facile and scalable method to synthesize well-defined single chain polystyrene nanoparticles through nitroxide-mediated polymerization and an intramolecular crosslinking reaction. In addition, even more complex architectures, where one or two polystyrene chains are attached to the SCNPs, are presented. A series of nanoparticles with different dimensions as well as different percent of crosslinking has been synthesized. Size exclusion chromatography (SEC), 1 H-NMR, dynamic light scattering (DLS) and viscometry were employed for the molecular and structural characterization of these nanomaterials. Other experimental techniques, such as differential scanning calorimetry (DSC), rheology and dielectric spectroscopy are used in order to study the unique melt properties of these nanostructures .

Maria-Malvina Stathouraki1, Apostolos Avgeropoulos2, Georgios Sakellariou3

1 INDUSTRIAL CHEMISTRY LABORATRORY, DEPARTMENT OF CHEMISTRY, NATIONAL & KAPODISTRIAN UNIVERSITY OF ATHENS PANEPISTIMIOPOLIS ZOGRAFOU, ATHENS 157 71, GREECE
2 DEPARTMENT OF MATERIALS SCIENCE ENGINEERING, UNIVERSITY OF IOANNINA, IOANNINA 45110, GREECE
3 INDUSTRIAL CHEMISTRY LABORATORY, DEPARTMENT OF CHEMISTRY, NATIONAL & KAPODISTRIAN UNIVERSITY OF ATHENS, PANEPISTIMIOPOLIS ZOGRAFOU, 15 771 ATHENS, GREECE

We report herein the modular synthesis and lithographic potential of linear and star block copolymers with low molar mass and high “Flory-Huggins” interaction parameter. Anionic, Ring-Opening (ROP) and Controlled/Living Radical Polymerizations (CRP) were employed along with high vacuum techniques for the polymer synthesis. These block copolymers incorporate highly incompatible blocks, such as poly(l-lactide), poly(dimethylsiloxane) and poly(2-vinylpyridine) and are termed as “high X ” polymers. Due to high incompatibility, low molar mass polymers allow for the formation of very small domain periods to be obtained. Size exclusion chromatography (SEC) light scattering and 1 H-NMR were employed for the molecular characterization of these polymers. Transmission electron microscopy (TEM) and small-angle X-ray scattering experiments (SAXS) were used to confirm the size and structure of the resulting nanomaterials.

Emmanouil Mygiakis1, Dimitrios Chatzogiannakis2, Emmanouil Glynos2, Georgios Sakellariou3

1 INDUSTRIAL CHEMISTRY LABORATORY, DEPARTMENT OF CHEMISTRY, NATIONAL & KAPODISTRIAN UNIVERSITY OF ATHENS
2 INSTITUTE OF ELECTRONIC STRUCTURE AND LASER, FOUNDATION FOR RESEARCH AND TECHNOLOGY
3 INDUSTRIAL CHEMISTRY LABORATORY, DEPARTMENT OF CHEMISTRY, NATIONAL AND KAPODISTRIAN UNIVERSITY OF ATHENS

Miktoarm star-shaped copolymers of Poly(styrene)nPoly(ethylene oxide)n were synthesized through a novel synthetic strategy that gives easy access to complex macromolecular architectures, through a controlled polymerization and post polymerization cross-link of the difunctional monomer, divinylbenzene (DVB). This approach offers the advantage of controlled and well defined products to the already known difunctional monomer chemistry, resulting in a synthetic route that combines low-cost and easily accessible reagents with short reaction times compared to silane chemistry. A series of linear triblock terpolymers, poly(styrene)-b-poly(divinylbenzene)-b-poly(ethylene oxide), were synthesized employing anionic polymerization via sequential monomer addition. Subsequently, the pending vinyl groups of the middle block were crosslinked, using AIBN as a free radical polymerization initiator, resulting in well-defined miktoarm star-shaped copolymers. Any residual unreacted linear triblock was easily removed by fractionation. These polymers were characterized with Size Exclusion Chromatography (SEC), Nuclear Magnetic Resonance Spectroscopy (NMR), Differential Scanning Calorimetry (DSC), Dynamic Light Scattering (DLS), Low Angle Light Scattering (LALS) and Viscometry.

Hermis Iatrou1, Panagiota Fragouli2, Panagiotis Christakopoulos1, Dimitra Stavroulaki1, Varvara Athanasiou2, Maria Kasimati1, Katerina Mathianaki2, Diana Kazarian2, Fotini Arfara2, Niki Roumelioti2

1 INDUSTRIAL CHEMISTRY LABORATORY, DEPARTMENT OF CHEMISTRY, NATIONAL & KAPODISTRIAN UNIVERSITY OF ATHENS, PANEPISTIMIOPOLIS ZOGRAFOU, 15 771 ATHENS, GREECE
2 INDUSTRIAL CHEMISTRY LABORATRORY, DEPARTMENT OF CHEMISTRY, NATIONAL & KAPODISTRIAN UNIVERSITY OF ATHENS PANEPISTIMIOPOLIS ZOGRAFOU, ATHENS 157 71, GREECE

Introduction. Cancer treatment remains a major challenge in medicine. Pharmaceutical scientists are trying to shift from traditional to novel drug delivery systems (DDS) by applying nanotechnology to medicine. While traditional therapeutic agents have allowed for very little control in terms of their distribution in the body and clearing times, engineering at the nanoscale level has allowed for significant advances in optimizing the biocompatibility, biodistribution, and pharmacokinetics. Although research to identify more efficient drugs is rapidly advancing, the discovery of novel materials with the required functionality is not progressing at the same rate. Methods. High vacuum techniques was used for the synthesis of the polymeric materials. Size exclusion chromatography, FTIR and NMR  spectroscopy was used for the characterization of the polymeric materials. Static and Dynamic laser scattering was used for the characterization of the polymers and the nanoconstructs. Rheology was used for the properties of the hydrogels.   Results . The nanoconstructs that were synthesized encapsulated efficiently large amounts of well-known and certified drugs for cancer treatment, like gemcitabine and everolimus. The delivery was targeted and in a sustained release profile. Conclusions. The collaboration of material as well as pharmaceutical scientists, biologists and clinical oncologists is imperative to produce efficient materials that possess advanced properties and required functionalities. Furthermore, advancements in drug design and the development of multifunctional nanocarriers from the combination of well-defined macromolecular architectures and smart materials are the future for the effective treatment of many lethal diseases such as cancer.  

NIKOLAOS PATELIS1, GEORGIOS SAKELLARIOU1

1 CHEMISTRY DEPARTMENT, NATIONAL AND KAPODISTRIAN UNIVERSITY OF ATHENS

Herein, we report a facile and scalable synthesis of ring polystyrenes from their linear counterparts. A series of different molecular weights linear polystyrenes ranging from 23 to 110 Kg/mol was synthesized by anionic polymerization using high-vacuum techniques. A few units of 4-vinyl benzocyclobutene were polymerized at both ends of the linear polystyrenes. Cyclization reaction took place through the o -quinodimethane intermediates, at high dilution conditions and high temperature, under inert atmosphere. The intramolecular cyclization proceeded with good yield as monitored by the size exclusion chromatography analysis. Highly pure ring polystyrenes were obtained after the fractionation utilizing liquid chromatography at the critical condition (LCCC).

Marinos Pitsikalis1, Stavros Zouganelis1, Eleftheria Batagianni1, Arkadios Marathianos1, Ekaterini Koraki1, Andreas-Philippos Maroudas1

1 INDUSTRIAL CHEMISTRY LABORATORY, DEPARTMENT OF CHEMISTRY, NATIONAL & KAPODISTRIAN UNIVERSITY OF ATHENS, ATHENS

METALLOCENE-MEDIATED CATIONIC POLYMERIZATION OF VINYL ETHERS. A NEW ROUTE FOR THE SYNTHESIS OF STATISTICAL, BLOCK AND GRAFT COPOLYMERS Stavros Zouganelis, Eleftheria Batagianni, Arkadios Marathianos, Ekaterini Koraki, Andreas-Philippos Maroudas and Marinos Pitsikalis* Department of Chemistry, National and Kapodistrian University of Athens, Panepistimiopolis Zographou 15771 Athens Greece   The cationic polymerization of ethyl, n -butyl, iso -butyl and chloroethyl vinyl ether, EVE, BVE, iBVE and CEVE respectively was efficiently conducted using bis(η 5 - cyclopentadienyl)dimethyl hafnium, Cp 2 HfMe 2 , or bis(η 5 - cyclopentadienyl)dimethyl zirconium, Cp 2 ZrMe 2 in combination with either tris(pentafluorophenyl)borate, B(C 6 F 5 ) 3 , or tetrakis(pentafluorophenyl)borate dimethylanilinum salt, [B(C 6 F 5 ) 4 ] - [Me 2 NHPh] + , as initiation systems. The evolution of polymer yield, molecular weight and molecular weight distribution with time was examined. In addition, the influence of the initiating system, the monomer and the reaction conditions on the control of the polymerization was studied. Furthermore, statistical copolymers of EVE with BVE were prepared employing Cp 2 HfMe 2 and [B(C 6 F 5 ) 4 ] - [Me 2 NHPh] + as the initiation system. The reactivity ratios were estimated using both linear graphical and non-linear methods. Structural parameters of the copolymers were obtained by calculating the dyad sequence fractions and the mean sequence length, which were derived using the monomer reactivity ratios. The glass transition temperatures, Tg, of the copolymers were measured by Differential Scanning Calorimetry, DSC, and the results were compared with predictions based on several theoretical models. The kinetics of thermal decomposition of the copolymers along with the respective homopolymers was studied by thermogravimetric analysis within the framework of the Ozawa-Flynn-Wall and Kissinger methodologies. Block copolymers of EVE with BVE and iBVE were synthesized and their micellization behavior was examined in organic selective solvents. Statistical copolymers of BVE and CEVE were synthesized and were employed as scaffolds for the synthesis of graft copolymers bearing poly(ε-caprolactone) or poly(L-lactide) branches by suitable click chemistry.

Aristeidis Papagiannopoulos1, Eleni Vlassi1

1 NATIONAL HELLENIC RESEARCH FOUNDATION, THEORETICAL AND PHYSICAL CHEMISTRY INSTITUTE, ATHENS

Introduction We use polysaccharide/protein complexation 1 between chondroitin sulfate (CS) and bovine serum albumin (BSA) in acidic conditions in combination with temperature-induced denaturation of BSA 2 to form well-defined, biocompatible, pH-stable nanoparticles. The ability of the thermally treated nanoparticles to act as nanocarriers of nutracuricals is proved by the effective encapsulation of β- carotene. Methods Porcine CS in the sodium salt form (Na-CS) (Bioiberica), bovine serum albumin (BSA) (Sigma-Aldrich) and β- carotene (Sigma-Aldrich) were used as recieved. Light scattering on an ALV system, circular dichroism on a Jasco J-815 spectrophotometer and other methods were used. Results In Figure 1 it is proved that the molar mass of the nanoparticles can be tuned by the CS/BSA mass ratio. Upon thermal treatment their mass increases but more importantly when pH changes from acidic to neutral swelling occurs due to transition of BSA from positive net charge to negative. Additionally pH change is not able to disintegrate the nanoparticles after thermal treatment. Conclusions                            This study demonstrates the role of proteins as both building blocks and nanocarriers inside multifunctional nanoparticles and can be used as a guide for other systems of polysaccharide/protein pairs and bioactive substances. References 1. Comert F, et al. (2016) Soft Matter 12 (18):4154-4161. 2. Schön A, et al. (2017) Proteins: Structure, Function, and Bioinformatics 85 (11):2009-2016. Figure 1: (a) Molar mass, (b) gyration and (c) hydrodynamic radius from CS/BSA nanoparticles (BSA 1 mgml -1 ), pH 4.2 (black), after thermal treatment at pH 4.2 (red) and after thermal treatment setting pH to 7 (blue).

Panagiotis Christakopoulos1, Barbara Athanasiou1, Diana Kazaryan1, Hermis Iatrou1

1 INDUSTRIAL CHEMISTRY LABORATORY, DEPARTMENT OF CHEMISTRY, NATIONAL & KAPODISTRIAN UNIVERSITY OF ATHENS

Cancer treatment remains a major challenge in medicine, with traditional cancer treatments including surgery complemented by  radiotherapy  and/or  chemotherapy. In response, pharmaceutical scientists and clinicians are trying to apply nanotechnology to medicine, in order to deliver drugs, genes and proteins with enhanced therapeutic efficacy, reduced dose and low dosing frequency, resulting in fewer side effects.   In this work the synthesis of copolymers containing varius polypeptides such as poly(L-histidine) and a terminal moiety that overexpress selectively on the surface of cancer cells is reported. For that purpose, a bifunctional poly(ethyleneglycol) (PEG) was used, featuring a terminal amine group as well as a terminal azide group. The amine group was used as the initiating species for the ring opening polymerization of the N-Carboxyanhydrites (NCA) of the amino acids and the azide group for the conjugation of cancer cell surface markers, via click chemistry. Such markers are folic acid and β -glycyrrhetinic acid. For the characterization of these polymers, a series of techniques took place like gel permiation chromatography (GPC), nuclear magnetic ressonance (NMR), infrarated and unltraviolet spectrospy (FT-IR, UV-vis) as well as dynamic and static light scattering (DLS, SLS). The results showed good molecular characterestics such as the polydispersity and the micelle size and it was also found that the cancer cell markers were attached at the copolymers.

Athanasios Skandalis1, Stergios Pispas2

1
2 NATIONAL HELLENIC RESEARCH FOUNDATION

Introduction Stimuli-responsive polymers are a new class of materials that exhibit reversible or irreversible changes in their chemical structures and/or physical properties, after the application of one or more external signals. In our work, we synthesized novel pH- and temperature- responsive PnBA-b-PNIPAM-b-PDMAEA amphiphilic triblock terpolymers and studied their properties in aqueous solutions. Methods The molecular weight and molecular weight distributions of the terpolymers were determined by SEC and their composition was determined by 1 H-NMR. Light scattering techniques (DLS, SLS, ELS) were utilized for the determination of mass, size, morphology and surface charge of the polymeric aggregates. Imaging of the terpolymer aggregates was achieved by TEM and AFM. Results PnBA-b-PNIPAM-b-PDMAEA triblocks were synthesized by RAFT polymerization. Methyl iodide (CH 3 ) was used in order to convert the PDMAEA tertiary amine groups into quaternary amine groups with permanent positive charges. In aqueous solutions, the triblocks self-assemble into micellar aggregates where PNIPAM and PDMAEA form the hydrophilic coronas and PnBA the hydrophobic cores. Significant changes are observed when variations of temperature and pH occur in the solution. Conclusions RAFT polymerization was successfully utilized for the synthesis of well-defined PnBA-b-PNIPAM-b-PDMAEA triblock terpolymers with different block ratios. The PDMAEA block was chemically modified in order to have permanent positive charge. In aqueous solutions, the terpolymers have been found to self-assemble into aggregates of micelles, showing also interesting structural changes with variation of solution temperature and pH.

Panagiota G. Fragouli1, Nikos Hadjichristidis2, Olli Ikkala3, Nikolay Houbenov3, Hermis Iatrou4, Johannes S. Haataja3, Vladimir Aseyev5, Rachid Sougrat2

1 UNIVERSITY OF WEST ATTICA
2 KING ABDULLAH UNIVERSITY OF SCIENCE AND TECHNOLOGY (KAUST)
3 AALTO UNIVERSITY ESPOO, FINLAND
4 NATIONAL AND KAPODISTRIAN UNIVERSITY OF ATHENS
5 UNIVERSITY OF HELSINKI, FINLAND

Through controlled high-vacuum anionic polymerization well-defined model polymers with complex macromolecular architectures having the highest molecular weight, structural and compositional homogeneity can be achieved. Block copolymers allow progressively ever more complex self-assemblies upon involving increasing number of the constituent blocks, where the structures are determined by the block lengths, block-block and block-solvent interactions, interface curvatures, and molecular topologies. To recognize the microphase domains in the complex multiblock copolymer structures using electron microscopy, is stimulus as the number of staining agents and their selectivity is restricted. Anionic polymerization high vacuum techniques were used to synthesize linear pentablock quintopolymers. Molecular characterization carried out by Size exclusion chromatography, Membrane Osmometry and Nuclear Magnetic Resonance. Differential Scanning Calorimetry was used for the characterization of the precursors and the final polymers. Dynamic Light Scattering and Transmission Electron Microscopy were used for the structure and properties of polymersomes. The multiblock multicomponent polymers exhibited a high degree of molecular and compositional homogeneity. The first reported suprapolymersomic structures that pentablock quintopolymer self-assembled were asymmetric, proposing practically new methods of producing directional drug release through the asymmetric polymersome membranes.   The conjunction of polymer chemistry and supramolecular chemistry interactions is required to synthesize multiblock copolymers, highly complex macromolecular superstructures with controlled internal structures and hierarchical solution-based self-assemblies suitable for nanochemistry, encapsulation, and biological applications. Moreover, in our belief, in complex diseases, very sophisticated structures should be designed to encapsulate a significant quantity of drugs, bypass biological barriers to effectively and selectively deliver the drug to the desired pathological site.

Stergios Pispas1

1

Introduction Triblock terpolymers present an interesting class of polymeric materials due to the formation of complex self-assembled nanostructures in solution and in the solid state, which may be utilized in several nano(bio)technological applications, including nanocarriers of bioactive compounds, nanotemplates and multifunctional films. So far RAFT polymerization has been rather scarcely utilized in the synthesis of triblock terpolymers. Methods Amphiphilic and pH and thermo-responsive triblock terpolymers of the types PDMAEMA-b-PLMA-b-POEGMA and PnBA-b-PNIPAM-b-PAA have been synthesized by RAFT polymerization, and molecularly characterized by SEC, NMR and FTIR spectroscopies. Their self-assembly and complexation properties towards lysozyme and DNA have been studied in aqueous media by DLS, SLS, ELS, SANS, TEM and fluorescence spectroscopy. Results Characterization results show that the synthetic schemes followed give well-defined triblock terpolymers with relatively narrow molecular weight distributions and predefined compositions and molecular weights. The terpolymers self-assemble in micellar aggregates with their structure and properties being influenced mainly by solution pH, temperature and ionic strength, as a result of the presence of selected responsive and functional blocks. The PDMAEMA-b-PLMA-b-POEGMA terpolymers can act as compaction agents for DNA, whereas PnBA-b-PNIPAM-b-PAA terpolymers can complex with lysozyme, followed by modulation of their thermoresponsive behavior. Conclusions Well-defined triblock copolymers with determined sequences of blocks have been synthesized by RAFT methodologies. The terpolymers self-assemble into supramolecular aggregates in aqueous media as a result of the physicochemical parameters of the medium. The terpolymer can act as carriers of nucleic acids and proteins and may find application in drug delivery protocols.

ΑΓΓΕΛΙΚΗ ΧΡΟΝΗ1, Stergios Pispas2

1
2 NATIONAL HELLENIC RESEARCH FOUNDATION

INTRODUCTION Amphiphilic block copolymers demonstrate a unique ability to self-assemble in aqueous solutions, forming well-defined polymeric micelles, which allows their utilization as drug and gene nanocarriers. Five well defined block copolymers consisting of a common hydrophobic poly(n-butyl acrylate) (PnBA) block, and a different hydrophilic block, i.e. poly(oligoethylene glycol acrylate) (POEGA) and poly(2-dimethylaminoethyl acrylate) (PDMAEA) respectively, were synthesized and studied in aqueous media. METHODS PnBA-b-POEGA and PnBA-b-PDMAEA block copolymers with different compositions were synthesized via RAFT polymerization. Their molecular weight (M w ), the polydispersity index (M w /M n ) and their chemical composition, were determined by SEC and 1 H-NMR. Aqueous solutions of the block copolymers were investigated by DLS and SLS, and critical micelle concentration (CMC), was determined by fluorescence spectroscopy. RESULTS The synthetic scheme followed for each copolymer system, resulted in well-defined diblocks having narrow molecular weight distributions and the desired compositions. DLS and SLS measurements have shown the formation of spherical aggregates in water. Results on the PnBA-b-PDMAEA diblock, indicate significant shrinkage of the aggregates at pH=3, probably indicating disaggregation in comparison to pH=7 solutions. All copolymers show low values of CMC in aqueous media, which depend on copolymer composition. CONCLUSION Amphiphilic PnBA-b-POEGA and PnBA-b-PDMAEA block copolymers were successfully synthesized using RAFT polymerization. In aqueous solutions, all copolymers form core/shell micelles, which either could be used as drug nanocarriers encapsulating hydrophobic drugs into the hydrophobic PnBA core or as gene delivery systems, where DNA/RNA could strongly bind with the PDMAEA corona.

George Malliaras1

1

One of the most important scientific and technological frontiers of our time is the interfacing of electronics with the living systems. This endeavour promises to help engineer better healthcare. Recent advances in organic electronics have made available conjugated polymers with a unique combination of attractive properties, including mechanical flexibility, mixed ionic/electronic conduction, enhanced biocompatibility, and capability for drug delivery [1–3]. I will present examples of novel devices for recording and stimulation of neurons and show that conjugated polymers offer tremendous opportunities to study the brain and treat its pathologies.   References [1]   Berggren, M. & Richter-Dahlfors, A. Organic Bioelectronics. Adv. Mater. 19, 3201–3213 (2007). [2]   Rivnay, J., Owens, R. M. & Malliaras, G. G. The Rise of Organic Bioelectronics. Chem. Mater. 26, 679–685 (2014). [3]    Someya, T., Bao, Z. & Malliaras, G. G. The rise of plastic bioelectronics. Nature 540, 379–385 (2016).

Jia-Jhen Kang1, Junpeng Zhao2, Stergios Pispas2, Christine M. Papadakis1

1 TECHNICAL UNIVERSITY OF MUNICH
2 THEORETICAL AND PHYSICAL CHEMISTRY INSTITUTE, NATIONAL HELLENIC RESEARCH FOUNDATION

Introductions Molecular brushes are densely grafted polymers composed of a polymeric backbone and side arms. Their complex architecture can easily be adjusted by changing the side arm architecture. In the present work, two amphiphilic molecular brushes differing in side arm architecture, diblock or random copolymer, are investigated, where the side arms contain poly(propylene oxide) (PPO) and poly(ethylene oxide) (PEO) segments. Since both monomers show lower critical solution behavior in aqueous solution, as the temperature is increased, a conformational transformation of the side arms is expected, and thus the molecular brushes.   Methods The temperature-dependent conformation of the molecular brushes with PPO- r -PEO and PPO- b -PEO side arms in dilute solution (2 wt% in D 2 O) is investigated by small-angle neutron scattering along with dynamic light scattering.   Results As temperature increases from room temperature, both kinds of brushes show decreasing hydrodynamic radius. Thereafter, the size of random brush starts to increase and shows a steep jump at 38 °C, where the single brush expands; while for the block copolymer brush, the size is rather stable before the expansion sets in at 60 °C.   Conclusions This model system provides insight into the effects caused by the thermoresponsive behavior of the PPO and PEO segments under the different steric constraints. With the same PPO/PEO weight ratio on the side arms, the temperature at which the molecule starts to expand is much lower for the random brush than that of the block copolymer brush.

Christos Politidis1, Stelios Alexandris1, Martin Steinhart2, George Floudas1

1 DEPARTMENT OF PHYSICS, UNIVERSITY OF IOANNINA, 45110 IOANNINA, GREECE
2 INSTITUT FÜR CHEMIE NEUER MATERIALIEN, UNIVERSITÄT OSNABRÜCK, D-49069 OSNABRÜCK, GERMANY

The effect of confinement on polymer dynamics and the associated liquid-to-glass temperature, T g , has been an issue of great interest in polymer physics. In this study, we investigate the effect of confinement in the nanometer scale on the dynamics of cis- 1,4-polyisoprene with molecular weights in the vicinity and over the entanglement limit ( M w =8500-100000 g/mol), confined in self-ordered nanoporous alumina (AAO) with diameters, d , ranging from 400 nm to 25 nm. An earlier study [1] investigated the effect of confinement in PI with M < M e and found an unaffected T g under confinement with respect to the bulk. Another study [2] reported on the effect of interfacial energy on the segmental dynamics for different polymers confined in AAO. Broadband Dielectric Spectroscopy (BDS) and Temperature-Modulated Differential Scanning Calorimetry (TMDSC) measurements were employed to examine the effect of confinement on molecular dynamics and the thermodynamic T g , respectively. For molecular weights higher than the entanglement limit (M w >10000 g/mol), BDS measurements revealed consistently faster segmental dynamics under confinement with respect to the bulk, leading to a decrease in T g with increasing degree confinement (2 R g / d ). In addition, we provide evidence for an intermediate process with an Arrhenius temperature dependence whose dielectric strength increases with increasing degree of confinement. This is attributed to a “dead layer” consisting of partially immobilized chains next to the interface, discussed in recent imbibition studies of polymers in nanopores and confirmed by theory [3], [4] . We further report on the effects of annealing and quenching on the thermodynamics and dynamics [5] . [1] Alexandris, S.; Sakellariou, G.; Steinhart, M.; Floudas, G. Dynamics of unentangled cis-1,4-polyisoprene confined to nanoporous alumina. Macromolecules 2014, 47, 3895?3900. [2] Alexandris, S.; Papadopoulos, P.; Sakellariou, G.; Steinhart, M.; Butt, H.-J.; Floudas, G. Interfacial Energy and Glass Temperature of Polymers Confined to Nanoporous Alumina Macromolecules 2016, 49, 7400-7414. [3] Yao, Y.; Alexandris, S.; Henrich, F.; Auernhammer G.; Steinhart, M.; Butt, H.-J.; Floudas, G. Complex dynamics of capillary imbibition of poly(ethylene oxide) melts in nanoporous alumina. J. Chem. Phys. 2017, 146, 203320. [4] Yao, Y.; Butt, H.-J.; Zhou, J.; Doi, M.; Floudas, G. Capillary Imbibition of Polymer Mixtures in Nanopores Macromolecules 2018 51, 3059-3065. [5] Politidis, C.; Alexandris, S.; Steinhart, M.; Floudas, G. High molecular weight cis-1,4-polyisoprene confined in nanoporous alumina: Dynamics over the entanglement limit (In preparation).

Evi Christodoulou1, Maria Nerantzaki1, Stravroula Nanaki1, Dimitrios Bikiaris1, Emmanouil Koutroubis1, Catherine Dendrinou-Samara1, Antonios D. Anastasiou2

1 DEPARTMENT OF CHEMISTRY, ARISTOTLE UNIVERSITY OF THESSALONIKI
2 UNIVERSITY OF LEEDS

Magnetic nanoparticles (MNPs) encapsulated in polymeric systems are promising materials for cancer treatment providing controlled and targeted drug delivery. In a previous work, D,L-lactide was for the first time successfully co-polymerized with the renewable monomer ω -hydroxyacid (TEHA) resulting in a fully bio-based material. In this study, these TEHA-co-PDLLA copolymers (with different TEHA/lactide ratios) were used to prepare the nanocarriers, which were further loaded with the anticancer drug Paclitaxel (PTX) and MnFe 2 O 4 NPs. PTX-loaded MNPs were prepared using a solid-in-oil-in-water (s/o/w) modified single emulsion-solvent evaporation method. SEM micrographs verified the successful formation of mainly spherical nanoparticles and TEM images ( Fig. 1a ) revealed their core-shell structure: magnetic core-polymer shell. FT-IR spectroscopy confirmed the successful encapsulation of paclitaxel and X-ray diffraction indicated the complete amorphization of the drug. DLS analysis confirmed the narrow size distribution of the nanoparticles (110-150 nm) and in vitro cytotoxicity testing ensured their low toxicity toward healthy cells, but also their great anticancer activity. The drug loading efficiency was high (~15%) in all cases and all materials exhibited high release rates and improved drug dissolution. The size and T g of the NPs have been found to play an important role on the drug release profile ( Fig. 1b ).

Fotini Machairioti 1, Panagiotis Bilalis2, Anastasia Nika1, Michalis Milidis1, Panagiota Petrou3, Sotiris Kakambakos3, Panagiotis Argitis3, Nikos Hadjichristidis2, Margarita Chatzichristidi1

1 NATIONAL AND KAPODISTRIAN UNIVERSITY OF ATHENS
2 KING ABDULLAH UNIVERSITY OF SCIENCE AND TECHNOLOGY (KAUST)
3 N.C.S.R. DEMOKRITOS

The design of surfaces having different hydrophilicity in specified areas is very important for guided biomolecule immobilization or cell adhesion. The predetermined immobilization of biomolecules on solid surfaces is critical for several biomedical and biotechnological applications such as biosensors, biological microelectromechanical systems (bio-MEMs) and microfluidic devices [1]. Lithography is a robust technique for the fabrication of well-defined structures with different shapes on surfaces. This technique is based on the solubility changes in a solvent (developer) of a polymer upon exposure. One common method is the deprotection of hydrophilic groups (e.g. carboxylic) with the help of a photoacid generator. Thus, the exposed areas are becoming more hydrophilic, than the unexposed ones, resulting in hydrophilicity changes on selected areas of the surface.   Taking advantage of the high hydrophobicity of fluoropolymers, as well as of the biomolecule-friendly solvents (hydrofluoroethers, HFEs) used for patterning on this polymer, we developed a process for biomolecule patterning on silicon surfaces by photolithography [2]. Different fluoropolymers (homo- and copolymers) were studied in function of patterning ability, hydrophilicity change upon exposure and biomolecule immobilization on the exposed and unexposed areas. The methods used for the biomolecule attachment to solid surfaces include physical adsorption and/or covalent coupling. We will discuss the solubility changes vs exposure dose, the effect of HFE and polar solvents on the exposed surfaces, as well as the ability of selective biomolecule immobilization. REFERENCES : [1] K.M. Midthun, et al. Biomacromolecules 14 (4) : 993, (2013) [2] P.G. Taylor, et al.  Adv. Mater. 21 (22): 2314 (2009)   ACKNOWLEDGEMENTS M.C. would like to greatly acknowledge the Dean of the Faculty of Science Professor I. Emmanouil for his financial support (SARG UoA 10812) to attend this Conference. The authors are also grateful to 3M Novec for providing the HFE solvents.

VARVARA ATHANASIOU1, PANAGIOTIS CHRISTAKOPOULOS2, DIMITRA STAVROULAKI1, NIKI ROUMELIOTI1, HERMIS IATROU1

1 INDUSTRIAL CHEMISTRY LABORATORY, DEPARTMENT OF CHEMISTRY, NATIONAL & KAPODISTRIAN UNIVERSITY OF ATHENS
2 INDUSTRIAL CHEMISTRY LABORATORY, DEPARTMENT OF CHEMISTRY, NATIONAL & KAPODISTRIAN UNIVERSITY OF ATHENS, ATHENS

Introduction. Over recent decades, various systems, such as polymeric micelles, vesicles, liposomes, and nanogels have been developed as nanocarriers that can effectively achieve the controlled delivery of anticancer drugs and genetic agents. Nanocarriers have expressed many benefits for cancer chemotherapy due to the minimization of serious side effects, resulting in improved therapeutic efficacy. Of these systems, stimuli-responsive carriers that sharply respond to changes in microenvironments of some pathological sites, such as, pH, temperature, redox, enzyme, have received considerable attention as fascinated potential drug delivery vehicles.   Methods. The synthesis of polymers was achieved through a one-step ring-opening polymerization (ROP) process of the corresponding protected N-carboxy anhydrides, using an amine end-functionalized poly(ethylene oxide) macroinitiator. High-vacuum techniques were used for the synthesis of the well-defined copolymers. Extensive molecular characterization studies were conducted in order to confirm the successful synthesis of the polymers.   Results. These amphiphilic copolymers of the Ν 3 -PEO- b -P(His) type possess the ability to self-assemble in aqueous media and form micelle-like nanostructures. The hydrophilic shell of the nanostructures was comprised of poly(ethylene oxide) chains, while the pH-responsive core was based on PHis.   Conclusions. This work opens avenues for the synthesis of multifunctional polymers containing this remarkable material that can allow for the fine tuning of the pH where the aggregates will be disrupted, leading to the control of the rate and choice of cellular compartment for the drug release. This is useful for the design of pH-stimuli responsive materials that can be e?ectively utilized for drug and gene delivery applications and theranostics.