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Most sophisticated biological functions and features of cells are based on self-organization, and the coordination and connection between their cell organelles determines their key functions. Therefore, spatially ordered and controllable self-assembly of polymersomes to construct clusters to simulate complex intracellular biological functions has attracted widespread attention. Here, we present a simple one-step copper-free click strategy to cross-link nanoscale pH-responsive and photo-cross-linked polymersomes (less than 100 nm) to micron-level clusters (more than 90% in 0.5-2 μm range). Various influencing factors in the clustering process and subsequent purification methods were studied to obtain optimal clustered polymeric vesicles. Even when polymeric vesicles separately loaded with different enzymes (glucose oxidase and myoglobin) are coclustered, the overall permeability of the clusters can still be regulated through tuning the pH values on demand. Compared with simple blending of those enzyme-loaded polymersomes, the rate of enzymatic cascade reaction increased significantly due to the interconnected complex microstructure established. The connection of catalytic nanocompartments into clusters confining different enzymes of a cascade reaction provides an excellent platform for the development of artificial systems mimicking natural organelles or cells.

In recent years, chitosan has attracted considerable interest in many fields due to its sufficient charge density under biological, non-hazardous conditions. Since chitosan originates from natural resources and has two different monomer units, its characterization must be carried out in a goal-oriented and precise manner. This work focuses on the characterization of chitosans most important parameters – solubility, crystallinity, degree of deacetylation (DD) and molecular weight – in a simple and convenient way. The DD was determined using Nuclear Magnetic Resonance spectroscopy (NMR), Particle Charge Detection (PCD), Fourier Transform Infrared spectroscopy (FTIR), CHN elemental analysis (CHN-EA) and conductometric/potentiometric titration with special attention to its physical state as solid or liquid. Investigation of DD by FTIR was successfully determined by calculating peak heights, peak areas and peak deconvolution from a linear combination of Gaussian and Lorentzian functions. Asymmetrical flow field flow fractionation with light scattering detection (AF4-LS) was applied in order to calculate molar masses and radii. In addition, pH-potentiometric titrations demonstrated a reproducible displacement of the point of zero charge (PZC) in form of a hysteresis depending on the titration direction. The DD affects the crystallinity, which was determined by deconvolution of the crystalline and amorphous domains.

Demand for direct chemical modification of functional material on a surface is increasing in various fields. A new approach for a functionalized surface is investigated by applying a conventional laser in order to generate chemical activation by photothermal energy. Poly(ethyleneimine) (PEI), with a high density of amino groups, is chemically grafted on poly(methyl methacrylate) (PMMA) by irradiation of a CO2 laser (10.6 μm). Laser parameters such as power, scan rate, and focal length are observed to play an important role in order to introduce effective photothermal energy for the chemical reaction between PEI and PMMA. By optimization of laser parameters, the amide compound is produced as a result of the reaction of amine from PEI and the ester of PMMA successfully. The PMMA surface modified with PEI is analyzed by XPS and TOF-SIMS to identify the functional groups. Furthermore, the surface is characterized in terms of wettability, adhesion force, and surface charge for various applications. Finally, reaction with dye and metal on the amine-terminated PMMA shows promising results in supplying a selective and reliable functional substrate.

The increasing demand and implementation of pharmaceutics poses severe risk to different aquatic species as detectable contaminant in almost every surface water worldwide. Diclofenac (DCF) as one of the most common used analgesics was investigated as contaminant to be removed by adsorption onto nanoporous poly(melamine-co-formaldehyde) (PMF) particles featuring a very high amount of nitrogen functionalities. To achieve a high specific surface area (up to 416 m

The human-made pollution of surface and ground waters is becoming an inevitable and persistently urgent problem for humankind and life in general, as these pollutants are also distributed by their natural circulation. For example, from mining activities and metallurgy, toxic heavy metals pollute the environment and present material risk for human health and the environment. Bioadsorbers are an intriguing way to efficiently capture and eliminate these hazards, as they are environmentally friendly, cheap, abundant, and efficient. In this study, we present brewers’ spent grain (BSG) as an efficient adsorber for toxic heavy metal ions, based on the examples of iron, manganese, cadmium, and nickel ions. We uncover the adsorption properties of two different BSGs and investigate thoroughly their chemical and physical properties as well as their efficiency as adsorbers for simulated and real surface waters. As a result, we found that the adsorption behavior of BSG types differs despite almost identical chemistry. Elemental mapping reveals that all components of BSG contribute to the adsorption. Further, both types are not only able to purify water to reach acceptable levels of cleanness, but also yield outstanding adsorption performance for iron ions of 0.2 mmol/g and for manganese, cadmium, and nickel ions of 0.1 mmol/g.

Catalytically active porous and hollow titania nanofibers encapsulating gold nanoparticles were fabricated using a combination of sol-gel chemistry and coaxial electrospinning technique. We report the fabrication of catalytically active porous and hollow titania nanofibers encapsulating gold nanoparticles (AuNPs) using a combination of sol-gel chemistry and coaxial electrospinning technique. The coaxial electrospinning involved the use of a mixture of poly(vinyl pyrrolidone) (PVP) and titania sol as the shell forming component, whereas a mixture of poly(4-vinyl pyridine) (P4VP) and pre-synthesized AuNPs constituted the core forming component. The core-shell nanofibers were calcined stepwise up to 600 °C which resulted in decomposition and removal of the organic constituents of the nanofibers. This led to the formation of porous and hollow titania nanofibers, where the catalytic AuNPs were embedded in the inner wall of the titania shell. The catalytic activity of the prepared Au@TiO2 porous nanofibers was investigated using a model reaction of catalytic reduction of 4-nitrophenol and Congo red dye in the presence of NaBH4. The Au@TiO2 porous and hollow nanofibers exhibited excellent catalytic activity and recyclability, and the morphology of the nanofibers remained intact after repeated usage. The presented approach could be a promising route for immobilizing various nanosized catalysts in hollow titania supports for the design of stable catalytic systems where the added photocatalytic activity of titania could further be of significance.

The modification of the biobased polymer chitosan is a broad and widely studied field. Herein, an insight into the hydrophobization of low-molecular-weight chitosan by substitution of amino functionalities with hexanoyl chloride is reported. Thereby, the influence of the pH of the reaction media was investigated. Further, methods for the determination of the degree of substitution based on 1H-NMR, FTIR, and potentiometric titration were compared and discussed regarding their accuracy and precision. 1H-NMR was the most accurate method, while FTIR and the potentiometric titration, though precise and reproducible, underlie the influence of complete protonation and solubility issues. Additionally, the impact of the pH variation during the synthesis on the properties of the samples was investigated by Cd2+ sorption experiments. The adjusted pH values during the synthesis and, therefore, the obtained degrees of substitution possessed a strong impact on the adsorption properties of the final material.

Composite solid surfaces with high content of functional groups (FGs) are useful materials in different types of applications requiring stimuli-responsive "hard/soft" architectures, their improved properties rising from the combination of organic-inorganic parts. Among different types of weak polyelectrolytes, poly(ethyleneimine) (PEI) is of great interest in the construction of composite systems with thin layer-by-layer (LbL) organic films due to the large number of amino groups per unit mass of polymer. Herein, the spherical silica microparticles were modified with linear (L) or branched (B) PEI chains using LbL deposition of a copper complex (PEIL-Cu

In this study, low molecular weight chitosan salt (LMWC-HCl) highly soluble in water was prepared from low molecular weight chitosan (LMWC) in the solid state exposed to hydrogen chloride gas as a reagent. The effects of chitosan particle size, exposure conditions, reaction temperature and reaction time were investigated on the solubility and the molecular weight of obtained products. The formation of the chloride salt was observed after 3 h in a range of temperatures from 4 to 50 °C. The solubility of prepared LMWC-HCl was over 98% for all samples, much higher than that of the original LMWC. The average molecular weight of the LMWC-HCl was about 20–90 kDa with a quite narrow distribution and lower compared to the LMWC. LMWC-HCl and LMWC showed the same high antibacterial activity against Bacillus cereus and Vibrio parahaemolyticus. This facile and efficient process for solubilization of LMWC has potential for industrial application of chitosan.

Polyethyleneimine (PEI) cryogels have been fabricated using poly(ethylene glycol) diglycidyl ether (DGE-PEG), 1,4-butanediol diglycidyl ether (DGE-1,4-BD), and glutaric aldehyde (GA) as cross-linking agents. The rate of PEI cross-linking changes in the order GA > DGE-1,4-BD > DGE-PEG. The established correlations between the modification degree, swelling, and static ion-exchange capacity revealed a tendency of diglycidyl ethers, especially DGE-1,4-BD, to graft as a side chain to PEI in alkaline media. Low reactivity of cross-linkers at temperatures below zero resulted in lower modification degree and higher sorption capacities of PEI cryogels in comparison with PEI cross-linked at room temperature. Due to the difference in mechanisms of sorption of metal cations and anions, PEI cryogels cross-linked with DGE-1,4-BD and DGE-PEG were the most efficient for sorption of Hg(II) as [HgCl4]2− complex and Cu(II) ions, respectively. The morphology of PEI cryogels depends on the type of the cross-linking agent, cross-linker/PEI molar ratio, and concentration of PEI solution; the pore volume of cryogels obtained under the same conditions decreased in the order GA > DGE-1,4-BD > DGE-PEG.

The immobilisation of silica nanoparticles on the surface of a flowing polymer melt is studied during injection moulding. We use silica nanoparticles of identical size of about 200 nm, but with different surface functionalities: plain unmodified particles with silanole groups as well as amino- and hydrocarbon modified particles. The particles were brought in contact with a polycarbonate melt at a temperature of 300 °C. In our investigation, we show that particles with polar surfaces are more embedded than those with non-polar surfaces. Immobilised polar particles exhibited also a higher adhesion, tested with an adhesive tape, whereas the non-polar particles can be easily removed by peeling off the adhesive tape. This paper reveals that surface properties have a larger influence on embedding of nanoparticles than thermal conditions due to cooling of the melt.

In this work, the flocculation efficiency of reacetylated chitosans were compared with those of commercially available chitosans. The flocculation properties were investigated in dispersion of clay by means of turbidity measurements, colloid titration and measurements of the floc size. Reacetylated chitosan dissolves in deionized water without any additives and exhibits good flocculation properties like a wider flocculation window but a higher amount of polymer. For commercial chitosan lower amounts of polymer were required for the flocculation of clay dispersion. Flocculation with commercial chitosan is possible even in basic range.

New types of composites were obtained by an autotemplate method for assembling hollow CaCO3 capsules by using pH-sensitive polymers. Five pectin samples, which differ in the methylation degree and/or amide content, and some nonstoichiometric polyelectrolyte complex dispersions, prepared with the pectin samples and poly(allylamine hydrochloride), were used to control the crystal growth. The morphology of the composites was investigated by scanning electron microscopy, and the polymorphs characteristics were investigated by FTIR spectroscopy. The presence of the polymer in the composite particles was evidenced by X-ray photoelectron spectroscopy, particle charge density, and zeta-potential. The new CaCO3/pectin hollow capsules were tested as a possible matrix for a tetracycline hydrochloride carrier. The kinetics of the drug release mechanism was followed using Higuchi and Korsmeyer–Peppas mathematical models.

Catalytically active porous and hollow titania nanofibers encapsulating gold nanoparticles were fabricated using a combination of sol-gel chemistry and coaxial electrospinning technique. We report the fabrication of catalytically active porous and hollow titania nanofibers encapsulating gold nanoparticles (AuNPs) using a combination of sol-gel chemistry and coaxial electrospinning technique. The coaxial electrospinning involved the use of a mixture of poly(vinyl pyrrolidone) (PVP) and titania sol as the shell forming component, whereas a mixture of poly(4-vinyl pyridine) (P4VP) and pre-synthesized AuNPs constituted the core forming component. The core-shell nanofibers were calcined stepwise up to 600 °C which resulted in decomposition and removal of the organic constituents of the nanofibers. This led to the formation of porous and hollow titania nanofibers, where the catalytic AuNPs were embedded in the inner wall of the titania shell. The catalytic activity of the prepared Au@TiO

Copper(II) as a heavy metal ion is posing risk to aquatic ecosystems including algae, fish, mollusks, and bacteria, negatively affecting human life because of bioaccumulation and non-biodegradability. In this study, two thermoresponsive PNIPAM-b-PAA block copolymers with different characteristics in terms of molecular weight and PAA composition were investigated to remove copper ions from simulated water. We chose to utilize those block copolymers in CuSO4 adsorption experiments in order to comprehend how the combination of the thermoresponsive PNIPAM block and the binding ability that PAA block offers, affects the adsorption of Cu2+ and SO42− and provides eventually their removal from aqueous solutions. The adsorption protocol includes simple mixing of the copolymer and CuSO4 aqueous solutions under stirring. Dynamic and electrophoretic light scattering, pH, UV–vis, turbidity and ICP-OES measurements were conducted to verify the PNIPAM-b-PAA ability as smart adsorbents. The results showed that the PNIPAM-b-PAA_50−50 sample offers the possibility of Cu2+ and SO42- adsorption of greater percentage especially when temperature increases to 60 °C. Therefore, PNIPAM-b-PAA block copolymers comprise efficient and smart Cu2+ and SO42- adsorbents.

Chitosan in the solid state has been degraded in a controlled way by treatment with hydrogen peroxide at room temperature. Chitosan was swollen in diluted NaOH, making it more susceptible to the peroxide treatment. The product has been characterized by intrinsic viscosity, FTIR infrared spectroscopy and roentgen diffraction. The molecular weight and the intrinsic viscosity were reduced significantly (about tenfold). The degree of deacetylation did not change. The chitosan product has a low viscosity (about 100 cP), a lower molecular weight (1.4 × 102 kDa), a high purity and a high crystallinity. It can be used in many potential applications. This method is easy and suitable for a large-scale process.

Als Folgeerscheinung des Bergbaus gelangen sowohl Schwermetallionen als auch verschiedene Anionen, wie Sulfat, Phosphat etc., in die Umwelt und kontaminieren damit Grund- und Oberflächenwässer. Für die Verockerung ist Eisenhydroxid in Form eines rotbraunen Ockerschlamms verantwortlich. Zusätzlich tritt im Spreewald zunehmende Versauerung durch stetig steigende Sulfatbelastung ein. Zur Beseitigung der Rückstände und zur Erhöhung der Wasserqualität können Chitosanpartikel eingesetzt werden. Chitosan ist ein natürlich vorkommendes, ökologisches Biopolymer mit den Eigenschaften eines Superadsorbers. Erstmalig konnten mit Chitosan sowohl Eisenionen als auch Sulfationen gleichzeitig abgetrennt werden. Diese wachsen als Eisensulfat- und Eisenhydroxid-Aggregate auf der Chitosanoberfläche.

Chitosan (flakes with a degree of deacetylation of 90%) was used as adsorbent for heavy metal ions in solution (copper, iron, nickel). The adsorption capacities were determined in dependence on the adsorption time and the initial metal salt concentration. With increasing adsorption time as well as the initial metal salt concentration the adsorption capacities increased. Highest adsorption capacity was achieved for copper(II)ions with 110 mg/L. Iron(II)- and nickel(II)ions adsorbed with an adsorption capacity of 80 mg/L. The surface of chitosan flakes were investigated before and after the adsorption process by SEM and SEM-EDX, respectively. The formation of crystal-like structures was observed by SEM analysis for the investigation of copper(II)sulfate and iron(II)sulfate. It has been noticed that iron(II)ions oxidized before the adsorption on chitosan occurs. In comparison, the adsorption of nickel salt resulted in a smooth layer on the chitosan surface. SEM-EDX analysis revealed that sulfate adsorbs on the chitosan surface besides the metal cations used.

The modification of silica microparticles surface with a high number of amino/carboxylic groups of polymer chains represent an interesting route to obtain nanostructured composite materials aiming different applications. Herein, four weak polycations (PC) [polyethyleneimine (PEI), polylysine (PLL), polyvinylamine (PVAm), polyallylamine hydrochloride (PAH)] and one weak polyanion [polyacrylic acid (PAA)] were layer-by-layer deposited onto spherical silica to form composite microparticles. A strategy where each deposited polycation layer was chemically cross-linked with glutaraldehyde (GA) prior to the deposition of PAA layer was used, forming at the end silica//(PC GA/PAA)n composite microparticles. Finally, we investigated the particles towards their adsorption properties on metal ions (Cu2+, Pb2+, Ni2+, and Fe2+) from simulated and real surface water, as a potential application for the composite particles.

The study confirms the interaction of sulfate ions (SO42−) into the polymer chains of chitosan under acidic conditions. As a result the crystallinity of chitosan decreases with (1) increasing protonation of the amino groups and (2) increasing SO42− concentration. The adsorption of iron ions (Fe2+/3+) resulting from (FeSO4)aq onto the chitosan surface takes place incidentally by the oxidative effect of Fe2+/3+ with formation of orthorhombic α-FeOOH and γ-FeOOH. The separation of iron and sulfate ions correlates stoichiometrically. Chitosan with different degrees of deacetylation (DD) were used in order to investigate the influence of DD on the adsorption behavior of iron and sulfate ions. The higher the DD of chitosan, the more iron and sulfate ions can be adsorbed. Langmuir isotherms showed good agreement with the adsorption data obtained (qDD=90 %(Fe) = 2.36 mmol g-1; qDD=90 %(SO42−) = 2.58 mmol g-1). After adsorption process, the adsorber was analyzed extensively via X-ray diffraction, FTIR, 13C-NMR, SEM/EDX measurements and Mossbauer spectroscopy.

Polymers 10(7), - (2018). doi:10.3390/polym10070791 special issue: "Special Issue "Microgels and Hydrogels at Interfaces" / Guest Editor Dr. Patrick van Rijn, Department of BioMedical Engineering FB-40, University of Groningen/University Medical Center Groningen; Dr. Felix Plamper, Institute of Physical Chemistry, RWTH Aachen University", Published by MDPI, Basel

In this conceptual contribution, thin functional coatings consisting of either pure polyelectrolytes (PELs) or complexes between oppositely charged PELs at model and applied substrates are outlined. Latter PEL/PEL complexes were deposited by two concepts. In a first well-known concept, PEL multilayers (PEM) were consecutively deposited according to the layer-by-layer (LbL) technique. In a second less known concept, PEL complex (PEC) nanoparticles (NPs) preformed by mixing polycation (PC) and polyanion (PA) solutions were deposited in one step. Both concepts based on binary oppositely charged PELs are compared to one based on a single polycation system. Examples shall be given on adhesiveness, nanostructure, and biomedical applications of PEM and PEC NP coatings. In situ attenuated total reflection (ATR) infrared (IR) spectroscopy, circular dichroism (CD), and scanning force microscopy (SFM) were used for molecular, optical, and microscopic characterization. At first, results on the adsorbed amount and wet adhesiveness of pure (single-component) PEL coatings as a function of charge density are given to motivate coatings of mixed oppositely charged PELs. Second, the wet adhesiveness of PEM and PEC NP coatings of identical PEL compounds in aqueous media varying the molar charge ratio ( n-/ n+) and the deposition step z, respectively, is compared. Upon comparing the three PEL deposition concepts, it is suggested that the lack or absence of excess charge at the PEL/surface interface is one of the main factors for the wet adhesiveness of all pure PEL, PEM, and PEC NP coatings. Finally, the potential of PEM and PEC NP coatings for biomedical applications is outlined. Concerning biopassivation, PEM coatings excessed or terminated by PA repel proteins with low isoelectric points. Concerning bioactivation, PEM coatings loaded with antibiotics as well as PEC NP coatings loaded with therapeutic bisphosphonates showed retarded, optionally temperature responsive drug release for applications in acute surgery and bone healing, and immunoglobulin/PEL complex coatings might open theranostic applications.

Composite microparticles of CaCO3 and two pectin samples (which differ by the functional group ratio) or corresponding nonstoichiometric polyelectrolyte complexes with different molar ratios (0.5, 0.9 and 1.2) are obtained, characterized and tested for loading and release of streptomycin and kanamycin sulphate. The synthesized carriers were characterized before and after drug loading in terms of morphology (by SEM using secondary electron and energy selective backscattered electron detectors), porosity (by water sorption isotherms) and elemental composition (by elemental mapping using energy dispersive X-ray and FTIR spectroscopy). The kinetics of the release mechanism from the microparticles was investigated using Higuchi and Korsmeyer–Peppas mathematical models.

The biodegradable polysaccharide chitosan possesses protonated and natural amino groups at medium pH values and has therefore been used as an adsorbing material for nickel salts in water treatment. Nickel is a problematic heavy metal ion which can cause various diseases and disorders in living organisms. Here, we show the influence of oxyanions (e.g., nitrate and sulfate) to the adsorption of nickel ions. Hence, simultaneously we are addressing the increasing global problem of nitrate and sulfate ion pollution in groundwater and surface water. A series of adsorption experiments was carried out in order to determine (i) the adsorption equilibrium, (ii) the adsorption capacity in dependence on the initial nickel ion concentration, and (iii) the influence of the anion presented in solution for the adsorption capacity. Surface morphology of chitosan flakes before and after the adsorption process has been studied with SEM-EDX analysis. The chitosan flakes exhibited promising adsorption capacities of 81.9 mg·g−1 and 21.2 mg·g−1 for nickel (sulfate) and nickel (nitrate), respectively. The calculated values of Gibbs free energy change ΔG0 confirm the higher adsorption of nickel ions in presence of sulfate ions. Hence, higher anion valence leads to a higher adsorption capacity.

As a consequence of mining, heavy metal ions can be exposed to the environment hence contaminate ground water and surface water amongst others. The natural polymer chitosan was proved to be an excellent adsorber material for the effective removal of iron and sulfate ions in batch as well as in column experiments. The adsorption behavior of iron ions, as well as sulfate ions was investigated by utilizing chitosan flakes as a natural adsorbent. The removal was studied using adsorbance measurements, SEM and SEM-EDX. The adsorption capacity of chitosan was determined at different times. The received adsorption capacities for iron ions were very promising with a maximum adsorption capacity of 85 mg/g and a rate of separation of 100%. The maximum adsorption capacity obtained for sulfate ions was 188.8 mg/g and a rate of 80%.

Five pectin samples – which differ by the methylation degree and/or amide content – were used to prepare inorganic/organic composites by CaCO3 mineralization from supersaturated solutions. The pectin chemical structure and concentration could control the composite superstructure by induction or orientation of crystal growth. The inorganic materials may also control CaCO3 polymorphism and morphologies and therefore different carbonate sources, such as Na2CO3, diethylcarbonate or ammonium carbonates, were used as modulators for crystal growth. The morphology of the new CaCO3/pectin composites was investigated by SEM and the polymorphs content by X-ray diffraction, as compared to bare CaCO3 samples prepared in similar conditions. The composites were tested as sorbents for Cu(II) and Ni(II) ions. Keywords: Pectin, CaCO3, Composite, Polymorph, Sorbent

Biologically degradable polymers based on renewable raw materials, such as polysaccharides, represent promising alternatives to synthetic polymers used as flocculants or stabilizing agents. Polysaccharides derived from potato starch have been modified with benzyl- and additionally cationic hydroxypropyl trimethyl ammonium groups of different degrees of substitution (DS). In this work these amphiphilic starch derivatives have been used to remove substances which impact negatively the paper production process when using recycled paper, so called stickies. Model suspensions have been studied using a multitude of different measurement techniques with the aim to predict a “sticky potential” and to reduce dissolved and colloidal substances such as micro-stickies. Systematic experiments studying the interactions between the novel amphiphilic starch derivatives and the model suspension have shown that dynamic surface tension is a very suitable property to characterize the surface active compounds in the model suspension giving additional information about the sticky potential of waste water, e.g. white water and offering a new and sensitive way to describe the parameter “hydrophobicity”. Moderately cationic and hydrophobic starch derivatives proved to be the most effective ones for sticky removal.

“Adsorption deinking” is a new concept for ink removal from suspensions using polymer particles instead of air bubbles (flotation) in a process with high efficiency, concerning the consumption of energy and water. We studied the influence of different papers and inks, of the deinking solution (compared with water), and of the duration of deinking. The process is characterized not only by the colour of polymer particles, but also by the properties in suspension such as charge, turbidity or particle size. Further it is shown, that dynamic surface tension is a useful tool to characterize not only the surfactant in suspension, but also its interaction with other substances (cellulose and ink). The efficiency of adsorption deinking is strongly influenced by the properties in suspension which depend on the type of paper.

Chitosan steht seit einigen Jahren im Fokus biologisch orientierter Forschung sowohl in der Modifizierung als auch in der Anwendung. Es hat eine Vielzahl von Vorteilen gegenüber synthetischen Produkten, es ist z. B. nicht toxisch. In dieser Arbeit wurden die Chitosane reacetyliert und charakterisiert. Reacetylierte Chitosane lösen sich ohne Zusätze in Wasser und zeigen gute Flockungseigenschaften. Die Flockung von reacetylierten und kommerziellen Chitosanen wurde verglichen. Molmasse, pH‐Wert und der Salzgehalt im System nehmen großen Einfluss auf die Lage und Breite der Flockungsfenster.