Types Of Synthetic Polymers Research Articles

Spontaneous Formation of π-Conjugated Polymeric Colloidal Molecules Through Stepwise Coacervation and Symmetric Compartmentalization.

Coacervation, the phase separation of liquid induced by polymeric solutes, sometimes results in the formation of oligomeric clusters of droplets. The morphology of the clusters is non-uniform because the clustering is a consequence of the random collisions of the drifting droplets. Herewereportdistinctively organized coacervation, yielding colloidal molecules with monodisperse size, morphological symmetry, and compositional heterogeneity.Weinvestigate the coacervation of a mixture of two types of synthetic polymers and find that one of the polymers coacervates first and serves as a core droplet, on which the other polymer coacervates subsequently to form satellite droplets. The satellite droplets arrange themselves symmetrically around the core and solidify without losing the morphology. The number of satellites and their symmetry are modulable depending on the chemical affinity and the diameter of the droplets. This finding highlights the capability of coacervation as a non-templated and non-covalent pathway to form aspherical colloidal materials with structural and functional complexity.

CHARACTERIZATION OF CORN STARCH EDIBLE FILMS BY THE ADDITION OF CHITOSAN AS A VEGETABLE OIL PACKAGING MATERIAL

Abstract - Vegetable oil packaging materials use a type of synthetic polymer that is harmful to the body and the environment. Edible film as an environmentally friendly packaging material can be a solution for vegetable oil packaging material. Edible films are made from natural ingredients such as starch and chitosan. The objective of this study is to determine the best conditions of addition of chitosan in making edible film in terms of its physio-chemicals and determine the best glycerol concentration in terms of its physical properties. The composition of raw materials in the form of corn starch is 5 grams and the composition of chitosan is (0,5%, 1% and 1,5% b/v). Glycerol concentrations vary in (4%, 5% and 6% v/v). the result of the analysis of the physical properties of the edible film through the analysis of the physical tensile strength test, namely the best composition on the addition of 1 gr chitosan as well as the elongation analysis at termination. Analysis of the solubility of the edible film at a concentration of 1 gr as well the analysis of water vapor permeability. Whereas the analysis of the best antioxidant capacity in the composition of chitosan is 1,5 gr. Keywords: corn starch, chitosan, edible film

Comparative investigation on heterotrophic denitrification driven by different biodegradable polymers for nitrate removal in mariculture wastewater: Organic carbon release, denitrification performance, and microbial community.

Heterotrophic denitrification is widely studied to purify freshwater wastewater, but its application to seawater wastewater is rarely reported. In this study, two types of agricultural wastes and two types of synthetic polymers were selected as solid carbon sources in denitrification process to explore their effects on the purification capacity of low-C/N marine recirculating aquaculture wastewater (NO3 --N 30 mg/L, salinity 32‰). The surface properties of reed straw (RS), corn cob (CC), polycaprolactone (PCL) and poly3-hydroxybutyrate-hydroxypropionate (PHBV) were evaluated by Brunauer-Emmett-Teller, Scanning electron microscope and Fourier-transform infrared spectroscopy. Short-chain fatty acids, dissolved organic carbon (DOC), and chemical oxygen demand (COD) equivalents were used to analyze the carbon release capacity. Results showed that agricultural waste had higher carbon release capacity than PCL and PHBV. The cumulative DOC and COD of agricultural waste were 0.56-12.65 and 1.15-18.75 mg/g, respectively, while those for synthetic polymers were 0.07-1.473 and 0.045-1.425 mg/g, respectively. The removal efficiency of nitrate nitrogen (NO3 --N) was CC 70.80%, PCL 53.64%, RS 42.51%, and PHBV 41.35%. Microbial community analysis showed that Proteobacteria and Firmicutes were the most abundant phyla in agricultural wastes and biodegradable natural or synthetic polymers. Quantitative real-time PCR indicated the conversion from nitrate to nitrogen was achieved in all four carbon source systems, and all six genes had the highest copy number in CC. The contents of medium nitrate reductase, nitrite reductase and nitrous oxide reductase genes in agricultural wastes were higher than those in synthetic polymers. In summary, CC is an ideal carbon source for denitrification technology to purify low C/N recirculating mariculture wastewater.

Airborne Microplastic in the Atmospheric Deposition and How to Identify and Quantify the Threat: Semi-Quantitative Approach Based on Kraków Case Study.

Airborne microplastic is an emerging and widespread pollutant yet is still under-characterised and insufficiently understood. Detailed description of microplastic air pollution is crucial as it has been identified in human lungs and remote locations, highlighting the atmosphere as a medium of MP dispersion and transportation. The lack of standardization of methods for measuring and further monitoring of microplastic pollution is an obstacle towards assessment of health risks. Since the first recognition of MP presence in the atmosphere of Krakow in 2019, this research was conducted to further characterise and develop the methods for qualitative and quantitative analysis of airborne microplastic (attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR); pyrolysis-gas chromatography–mass spectrometry (Py-GC–MS); scanning electron microscopy-energy dispersive spectroscopy SEM-EDS) and pre-treatment of samples. The data were gathered in seven cycles from June 2019 to February 2020. The methods used in the study allowed the identification and analysis of the changing ratio of the different types of synthetic polymers identified in the atmospheric fallout (low-density polyethylene, nylon-66, polyethylene, polyethylene terephthalate, polypropylene and polyurethane). Observations of interactions between microplastic particles and the environment were conducted with analyses of surface changes due to degradation. Different phases attached to the microplastics surfaces, with some of the inorganic contaminants transported on these surfaces determined also to be of anthropogenic origin. The methodology proposed in this study allows further characterisation of microplastic from multiple locations to provide highly comparable data, leading to identification of the sources of this phenomenon, as well as seasonal changes.

Applications of Synthetic Polymer Discoidal Lipid Nanoparticles to Biomedical Research.

Liposomes are artificially prepared vesicular lipid nanoparticles with a bilayer structure, resembling cell membrane. Their ability to encapsulate various molecules along with excellent biocompatibility makes them ideal delivery vehicles for pharmaceuticals. They can also serve as platforms for membrane proteins to elucidate the structure and function in lipid membranes. Nascent high-density lipoproteins are discoidal lipid nanoparticles with a bilayer structure, which can be reconstituted with their constituents. Such reconstituted nanoparticles, nanodisks, were originally generated in terms of elucidation for mechanisms of lipoprotein metabolisms. At the same time, like liposomes, nanodisks have been developed as delivery vehicles and platforms for membrane proteins in structural biology. From a developmental background, apolipoproteins, their analogs, or fragment peptides were initially used as scaffolding molecules to wrap around the edge of the disk-shaped lipid bilayer. Since the discovery that styrene-maleic acid copolymers produce nanodisks instead of apolipoproteins, variously modified or novel polymers have been synthesized to broaden the applications of polymer nanodisks. This review provides an overview of the types of synthetic polymers used to produce nanodisks, and the biomedical applications of nanodisks to the developments of delivery vehicles and to the structural studies of membrane proteins.

THE PREPARATION AND BIODEGRADATION OF POLYBLEND PLASTIC FILM LOW-DENSITY POLYETHYLENE WITH PCL OBTAINED USING BIS(DIBENZOYLMETHANE)ZIRCONIUM(IV) CATALYST

Low-Density Polyethylene (LDPE) is a type of synthetic polymer that is non-biodegradable and difficult to decompose by microorganisms. One solution to overcome this problem is to mix LDPE with a biodegradable polymer such as poly(ε-caprolactone) (PCL). The aim of this present study was to obtain an LDPE/PCL polyblend that can decompose in nature. The PCL used in this study was obtained from ROP ε-CL using a bis(dibenzoylmethanato)zirconium(IV) chloride catalyst. In this research, LDPE and PCL were mixed by the solvent casting method. While the solvent used is xylene. After that, the compatibility test, thermal properties test, and biodegradation test were carried out. Furthermore, the results of the biodegradation test showed that the LDPE/PCL polyblend produced could be degraded in the soil at a degradation rate of 3% for 60 days.

Formulation and optimization of synthetic polymer based herbal emulgel for anti-microbial activity

The aim of the present research was to develop and evaluate the anti-microbial emulgel by using three different types of synthetic polymers. The active moiety selected for the formulation was the seeds of Carica papaya fruit. The formulation was developed by performing the extraction process; Soxhlet extraction with ethanol and water. The seeds of Carica papaya are reported to have anti-microbial properties. The skin-friendly i.e., the topical formulation was selected for development. Emulgel was prepared by incorporating different polymers and then evaluating each of them for best results. Basic evaluation parameters such as organoleptic parameters, viscosity, consistency, pH, homogeneity have been done, which demonstrate the results as per the reference and standard articles. Along with that, qualitative and quantitative tests of Carica seeds have also been performed, which indicates that the selected plant material is safe for usage. Finally, the most imp test, the anti-microbial test has been performed for determining the efficacy of prepared emulgel. Hence, it can be concluded that the prepared emulgel is safe and best for topical use as an anti-microbial.

One-step preparation and characterization of silk nano- and microspheres

The present study described a new method with one step to fabricate silk fibroin nano- and microspheres, with the size of spheres and crystalline structure being controllable during processing. Polyethylene glycol, a type of synthetic polymer that is widely used in the pharmaceutical industry as a formulation excipient, was utilized to induce silk fibroin to self-assemble into nano- and microspheres. The addition of a certain amount of salt in the blending solution with subsequent titration into ethanol could improve the size dispersion, yield, and crystalline β-sheet structure (silk II) compared to those prepared without salt addition during preparation. Silk microspheres prepared in the presence of salts were less porous and more homogeneous in size than those prepared in the absence of salts. The present study described a new method with one step to fabricate silk fibroin nano- and microspheres, with the size of spheres and crystalline structure being controllable during processing. Silk microspheres prepared in the presence of salts were less porous and more homogeneous in size than those prepared in the absence of salts (Control). These properties are important not only for the stabilization of particles but also for the controlled release of entrapped drug molecules.

Identification algorithm for polymer mixtures based on Py-GC/MS and its application for microplastic analysis in environmental samples

Microplastics pollution is an acknowledged global issue, and new strategies are required to meet the increasing demand of standardized, fast and reliable measurements. Analytical pyrolysis coupled to gas chromatography and mass spectrometry (Py-GC/MS) is a promising technique to obtain qualitative and quantitative data on microplastics mixtures through the selection of a set of characteristic pyrolysis products for each polymer. However, this data processing method is time-consuming, and no automated algorithms are currently available. In the present work, a new method for the qualitative analysis of eleven types of synthetic polymers was developed, automated and implemented in the F-Search software, with the aim of proposing a standardized procedure for data processing in Py-GC/MS analysis of plastics mixtures. The method improves on the current literature, and is based on the generation of summated mass spectra (SMS) for each polymer, obtained by extracting specific m/z and retention index coordinates corresponding to characteristic pyrolysis products. The identification of a polymer is performed by comparing its SMS with those of a built-in library. After validation, the algorithm was tested on a reference sample containing all eleven investigated polymers. The algorithm provided relative standard deviations around 10%, and the results were used to estimate the lowest amount of polymer detectable in a sample, which was found lower than 1 μg for most polymers. The performance of the algorithm was also evaluated on a real sample from ocean water trawling, providing positive results for four different polymers. The performances of the algorithm are discussed, and possible future developments are outlined.

Pengaruh Berat Katalis Zeolit Alam terhadap Pencairan Limbah Ban dalam Bekas Kendaraan Bermotor Roda Dua Menjadi Bahan Bakar Cair

The productivity of Indonesia's tire industry is expected to be higher following the growth of domestic and global motor vehicle production. Along with that, waste used tires that are not used in the environment are increasing. Rubber-based tires, is one type of synthetic polymer (Polystyrene). Polystyrene cannot be easily recycled so that the processing of polystyrene waste must be done properly so as not to harm the environment. Polystyrene pyrolysis process is one way to minimize the polystyrene waste. The pirlolysis process is carried out with temperature operating conditions of 400 oC, weight of tire rubber 3000 grams with variations of catalyst 2%, 4% and 6% for 3 hours. The results showed that the more catalysts used the% CHP Conversion produced would be greater, the best results on the 6% catalyst were as much as 41.073%. Based on the results of the analysis using GC-MS, Used inner tire pyrolysis oil has the following hydrocarbon chains: (C1-C5) as much as 0.33%, (C5-C12) as much as 88.96% and (C10-C28) 10.71%. Hydrocarbon compounds contained in the oil from used tire pyrolysis contain many aromatic compounds

Unified Etching and Protection of Faceted Silver Nanostructures by DNA Oligonucleotides

Single-stranded DNA oligonucleotides have been widely used to functionalize metal nanoparticles, and the nanoparticles are often assumed to be stable. We herein communicate that DNA can both protect and etch silver nanomaterials, such as triangular plates (AgTPs). For DNA moieties with a high affinity to Ag such as polycytosine (poly-C) and polyguanine (poly-G), they display concentration-dependent etching, and the DNA length was vital. Etching was less effective when DNA is folded into more compact structures. Polythymine (poly-T) DNA is adsorbed very weakly on silver and it cannot etch the AgTPs. Instead, poly-T DNA effectively protects AgTPs from oxidation or dissolution against various etching conditions including Br–, Hg2+, H2O2, and heat. Compared to other types of synthetic polymers, poly-T DNA shows a much stronger protection effect. The change from protection to etching can be rationalized based on the interaction strength with silver. Adsorbed DNA can protect the AgTPs, while a high concentratio...

Nanohydroxyapatite Effect on the Degradation, Osteoconduction and Mechanical Properties of Polymeric Bone Tissue Engineered Scaffolds.

BACKGROUNDStatistical reports show that every year around the world approximately 15 million bone fractures occur; of which up to 10% fail to heal completely and hence lead to complications of non-union healing. In the past, autografts or allografts were used as the “gold standard” of treating such defects. However, due to various limitations and risks associated with these sources of bone grafts, other avenues have been extensively investigated through which bone tissue engineering; in particular engineering of synthetic bone graft substitutes, has been recognised as a promising alternative to the traditional methods.METHODSA selective literature search was performed.RESULTSBone tissue engineering offers unlimited supply, eliminated risk of disease transmission and relatively low cost. It could also lead to patient specific design and manufacture of implants, prosthesis and bone related devices. A potentially promising building block for a suitable scaffold is synthetic nanohydroxyapatite incorporated into synthetic polymers. Incorporation of nanohydroxyapatite into synthetic polymers has shown promising bioactivity, osteoconductivity, mechanical properties and degradation profile compared to other techniques previously considered.CONCLUSIONScientific research, through extensive physiochemical characterisation, in vitro and in vivo assessment has brought together the optimum characteristics of nanohydroxyapatite and various types of synthetic polymers in order to develop nanocomposites of suitable nature for bone tissue engineering. The aim of the present article is to review and update various aspects involved in incorporation of synthetic nanohydroxyapatite into synthetic polymers, in terms of their potentials to promote bone growth and regeneration in vitro, in vivo and consequently in clinical applications.

Routing of individual polymers in designed patterns.

Synthetic polymers are ubiquitous in the modern world, but our ability to exert control over the molecular conformation of individual polymers is very limited. In particular, although the programmable self-assembly of oligonucleotides and proteins into artificial nanostructures has been demonstrated, we currently lack the tools to handle other types of synthetic polymers individually and thus the ability to utilize and study their single-molecule properties. Here we show that synthetic polymer wires containing short oligonucleotides that extend from each repeat can be made to assemble into arbitrary routings. The wires, which can be more than 200 nm in length, are soft and bendable, and the DNA strands allow individual polymers to self-assemble into predesigned routings on both two- and three-dimensional DNA origami templates. The polymers are conjugated and potentially conducting, and could therefore be used to create molecular-scale electronic or optical wires in arbitrary geometries.

Unique structure and property of dendrimers in biomedical applications

Restricted accessMoreSectionsView Full TextView PDF ToolsAdd to favoritesDownload CitationsTrack Citations ShareShare onFacebookTwitterLinked InRedditEmail Cite this article Chai Minghui 2010Unique structure and property of dendrimers in biomedical applicationsProc. R. Soc. A.4661441–1443http://doi.org/10.1098/rspa.2010.0072SectionRestricted accessSpecial featureUnique structure and property of dendrimers in biomedical applications Minghui Chai Minghui Chai [email protected] Google Scholar Find this author on PubMed Search for more papers by this author Minghui Chai Minghui Chai [email protected] Google Scholar Find this author on PubMed Search for more papers by this author Published:10 March 2010https://doi.org/10.1098/rspa.2010.0072ReferencesAppelhans D., Oertel U., Mazzeo R., Komber H., Hoffmann J., Weidner S., Brutschy B., Voit B.& Ottaviani M. F.. 2010Dense-shell glycodendrimers: UV/Vis and electron paramagnetic resonance study of metal ion complexation. Proc. R. Soc. A 466, 1489-1513(doi:10.1098/rspa.2009.0107). Google ScholarBarth R. F., Adams D. M., Soloway A. H., Alam F.& Darby M. V.. 1994Boronated starburst dendrimer-monoclonal antibody immunoconjugates: evaluation as a potential delivery system for neutron capture therapy. Bioconjugate Chem. 5, 58-66(doi:10.1021/bc00025a008). Crossref, PubMed, ISI, Google ScholarChauhan A. S., Jain N. K.& Diwan P. V.. 2010Pre-clinical and behavioural toxicity profile of PAMAM dendrimers in mice. Proc. R. Soc. A 466, 1535-1550(doi:10.1098/rspa.2009.0448). Google ScholarHofacker A. L.& Parquette J. R.. 2010Amplification of local chirality within a folded dendrimer. An intramolecular ‘sergeants and soldiers’ experiment. Proc. R. Soc. 466, 1469-1487(doi:10.1098/rspa.2009.0274). Link, Google ScholarHowell B. A.& Fan D.. 2010Poly(amidoamine) dendrimer-supported organoplatinum antitumour agents. Proc. R. Soc. A 466, 1515-1526(doi:10.1098/rspa.2009.0359). Google ScholarKlajnert B., Pikala S.& Bryszewska M.. 2010Haemolytic activity of polyamidoamine dendrimers and the protective role of human serum albumin. Proc. R. Soc. A 466, 1527-1534(doi:10.1098/rspa.2009.0050). Google ScholarKobayashi H., Kawamoto S., Jo S.-K., Bryant H. L., Brechbiel M. W.& Star R. A.. 2003Macromolecular MRI contrast agents with small dendrimers: pharmacokinetic differences between sizes and cores. Bioconjugate Chem. 14, 388-394(doi:10.1021/bc025633c). Crossref, PubMed, ISI, Google ScholarSimanek E. E., Abdou H., Lalwani S., Lim J., Mintzer M., Venditto V. J.& Vittur B.. 2010The 8 year thicket of triazine dendrimers: strategies, targets and applications. Proc. R. Soc. A 466, 1445-1468(doi:10.1098/rspa.2009.0108). Google ScholarSolassol J., et al.2004Cationic phosphorus-containing dendrimers reduce prion replication both in cell culture and in mice infected with scrapie. J. Gen. Virol. 85, 1791-1799(doi:10.1099/vir.0.19726-0). Crossref, PubMed, ISI, Google ScholarThayumanavan S., Bharathi P., Sivanandan K.& Vutukuri D. R.. 2003Towards dendrimers as biomimetic macromolecules. C. R. Chim. 6, 767-778(doi:10.1016/j.crci.2003.08.007). Crossref, ISI, Google Scholar Previous ArticleNext Article VIEW FULL TEXT DOWNLOAD PDF FiguresRelatedReferencesDetailsCited by Amanullah M (2013) Dendrimers and Dendritic Polymers - Application for Superior and Intelligent Fluid Development for Oil and Gas Field Applications SPE Middle East Oil and Gas Show and Conference, 10.2118/164162-MS, , Online publication date: 10-Mar-2013. Damar K and Odaci Demirkol D (2011) Modified gold surfaces by poly(amidoamine) dendrimers and fructose dehydrogenase for mediated fructose sensing, Talanta, 10.1016/j.talanta.2011.09.042, 87, (67-73), Online publication date: 1-Dec-2011. This Issue08 May 2010Volume 466Issue 2117 Article InformationDOI:https://doi.org/10.1098/rspa.2010.0072Published by:Royal SocietyOnline ISSN:1471-2946History: Manuscript received09/02/2010Manuscript accepted09/02/2010Published online10/03/2010Published in print08/05/2010 License:© 2010 The Royal Society Citations and impact Subjectsbiochemistrymedicinal chemistry

Layer-by-layer fabrication of well-packed gold nanoparticle assemblies guided by a β-sheet peptide network

In this study, we describe the first demonstration of well-ordered multilayer thin films of gold nanoparticles through a layer-by-layer (LbL) technique assisted by a polypeptide template. Anionic poly(L-glutamic acid) (PLGA)-modified gold nanoparticles were prepared as building units for LbL self-assembly. Two types of synthetic polymers, poly(L-lysine) (PLL) and poly(allylamine), were used as polycations that carry the same amino groups at the side chain, although the former is a polypeptide and the latter is a vinyl polymer. The deposition process and the resultant multilayer films were characterized by means of absorption, circular dichroism, Fourier transform infrared and atomic force microscopy measurements. Experimental results revealed that LbL multilayer properties, such as thickness, conformation of the peptide component, homogeneity and periodicity of nanoparticle layers, were significantly affected by the kind of polycations present. In particular, the combination of anionic PLGA-coated gold nanoparticles and cationic PLL induced β-sheet formation, which enabled the fabrication of a homogeneously well-packed gold nanoparticle multilayer without aggregation. LbL multilayer properties such as thickness, conformation of the peptide component, homogeneity and periodicity of nanoparticle layers were significantly affected by the kind of polycations. The combination of anionic PLGA-coated gold nanoparticle and cationic PLL induced a β-sheet formation, which enables the fabrication of a homogeneously well-packed gold nanoparticle multilayer without aggregation.

Progress in the characterization of synthetic (supramolecular) polymers by analytical ultracentrifugation.

Analytical ultracentrifugation (AUC) is the leading technique for determining the molar mass, state of association in solution, and association constants of biological macromolecules. Even though it is little used for supramolecular polymers, this technique has already been shown to represent one of the best options in the characterization of these systems. The use of supramolecular assemblies in the field of nanotechnology requires the arrangement of such systems on surfaces, from solution. Therefore, the control and investigation of solution properties is of major importance. In this contribution we highlight the applicability and advantages of using AUC by presenting a summary of the results of the past few years on the characterization of various types of synthetic polymers and supramolecular polymer systems.

Polymeric materials of the future based on renewable plant resources and biotechnologies: Fibres, films, plastics

I begin with what Zakhar Aleksandrovich Rogovin said back in 1967: Natural polymers have the widest raw materials base. In contrast to the raw material used for manufacturing different types of synthetic polymers (natural gas, crude oil, coal) which are gradually being depleted despite the large reserves and cannot be restored in future decades and even centuries, the raw material resources for isolation of natural polymers (celluloses in particular) will not diminish when utilized rationally but can be renewed in any practically required quantities in very short times” [1]. Who could say it better!

Design of “Smart” polymers that can ­direct intracellular drug delivery

AbstractOne of the important characteristics of biological systems is their ability to change important properties in response to small environmental signals. The molecular mechanisms that biological molecules utilize to sense and respond provide interesting models for the development of “smart” polymeric biomaterials with biomimetic properties. An important example of this is the protein coat of viruses, which contains peptide units that facilitate the trafficking of the virus into the cell via endocytosis, followed by delivery of the genetic material out of the endosome into the cytoplasm, and from there into the nucleus. We have designed several new types of synthetic polymers to facilitate intracellular trafficking of drugs. One of these has been designed to mimic the specific peptides on viral coats that facilitate endosomal escape. Another has been designed to contain pH‐degradable bonds, facilitating endosomal escape of the drug only after the bonds are degraded at the acidic pHs of the endosomes. Both types of polymer are responsive to the lowered pH within endosomes, leading to disruption of the endosomal membrane and release of important biomolecular drugs such as DNA, RNA, peptides and proteins to the cytoplasm before they are trafficked to lysosomes and degraded by lysosomal enzymes. In this article, we review our work on the design, synthesis and action of such smart, pH‐sensitive polymers. Copyright © 2003 John Wiley & Sons, Ltd.

Dynamical structure of water around biopolymers investigated by microwave dielectric measurements using time domain reflectometry method

The dynamical structure of free water around biopolymers, such as gelatin, collagen, and globular proteins, has been characterized based on relaxation time, τ, and Cole–Cole parameter, β, obtained from microwave dielectric measurements using a time domain reflectometry method. As reported previously, the plots of β against τ for free water in seven types of synthetic polymers in aqueous solutions against τ are classified into two groups based on polymer hydrophilicity. It is indicated that the dynamical structure of water around low-hydrophilic polymers is more uniform than those around high-hydrophilic polymers. In the present work, the plots for the aqueous gels of gelatin and globular protein in aqueous solutions indicate the same feature as those for high-hydrophilic polymers. It can be expected that the dynamical structure of free water around biopolymers is uneven. However, the water structure around collagen appears to be uniform, although collagen consists almost of the same peptide chains as those of gelatin. These results suggested that the water structure around highly ordered polymers, e.g., collagen, is also uniform.

Time-delayed extraction matrix-assisted laser desorption/ionization time-of-flight mass spectrometry of polyacrylnitrile and other synthetic polymers with the matrix­4-hydroxybenzylidene malononitrile

Matrix selection and sample preparation technique, namely finding a suitable matrix–analyte combination, has been one of the most important concerns in applying positive and negative ion matrix-assisted laser desorption/ionization (MALDI) mass spectrometry to synthetic polymers. Most matrices used in MALDI have been selected for their sound performance in biopolymer analysis. We evaluated fourteen different matrices for the analysis of polystyrene (non-polar, organic solvent soluble), polymethylmethacrylate (semipolar, organic solvent soluble), polyethyleneglycol (polar, water soluble) and with special emphasis on polyacrylnitrile (semipolar, organic solvent soluble) by UV (337 nm) MALDI-MS employing time-delayed extraction (short fixed delay time of 156 ns). As standard matrix deposition technique we applied the so-called thin layer technique due to the good mass resolution which is obtainable. Among the matrices tested 4-hydroxybenzylidene malononitrile has been found to be the only useful matrix material for all four types of synthetic polymers at 337 nm laser wavelength and the thin layer sample preparation technique. Concerning the characterization of polyacrylnitrile, a difficult but important class of synthetic polymers, 4-hydroxybenzylidene malononitrile turned out to be the only successful MALDI matrix. By applying this matrix in combination with the thin layer preparation technique and time-delayed extraction excellent results in terms of resolution and sensitivity could be obtained in the positive as well as in the negative ion mode. Furthermore, various inorganic salt additives to the matrix 4-hydroxybenzylidene malononitrile were evaluated and the addition of ammonium hydrogen carbonate gave best results for polyacrylnitrile with a low polydispersity. © 1998 John Wiley & Sons, Ltd.