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Photopolymerization of diacetylenes usually requires stringent reaction conditions like high energy irradiation of 254-nm light or even γ-rays, which are generally harmful to the human body and thus mild conditions with lower energy irradiation are required. In this study, different diphenyldiacetylene (DPDA) derivatives were rationally designed followed by the investigation of their photopolymerization behavior. It was found that the para-substituted amino groups could render the absorption band of DPDA bathochromically shifted, ensuring a 365-nm light wavelength coverage. On this basis, an organogel system was constructed by chemically modifying cholesteryl and lipoic acid onto the DPDA moiety in aromatic solvents. Such uniform self-assemblies further facilitated to a rather high degree of polymerization by 365-nm irradiation. As a kind of fluorescent materials, the whole polymerization process of this system can be visualized by a photoluminescent signal.

Homogeneous gold (Au) complexes have demonstrated tremendous utility in modern organic chemistry; however, their application for the synthesis of polymers remains rare. Herein, we demonstrate the first catalytic application of Au complexes toward the polycondensation of alkyne-containing comonomers and heteroarene nucleophiles. Polymerization occurs through successive intermolecular hydroarylation reactions to produce high molecular weight aromatic copolymers with 1,1-disubstituted alkene backbone linkages. Clear correlations between the rate and degree of polymerization (DP) were established based on catalyst structure and counterion pairing, thus enabling polymerization reactions that proceeded with remarkable efficiency, high reactivity, and exceptional DPs. The reactivity is broad in scope, enabling the copolymerization of highly functionalized aromatic and aliphatic monomers. These results highlight the untapped utility of Au catalysis in providing access to new macromolecular constructs.

Polymerization‐induced self‐assembly (PISA) enables the scalable synthesis of functional block copolymer nanoparticles with various morphologies. Herein we exploit this versatile technique to produce so‐called “high χ–low N” diblock copolymers that undergo nanoscale phase separation in the solid state to produce sub‐10 nm surface features. By varying the degree of polymerization of the stabilizer and core‐forming blocks, PISA provides rapid access to a wide range of diblock copolymers, and enables fundamental thermodynamic parameters to be determined. In addition, the pre‐organization of copolymer chains within sterically‐stabilized nanoparticles that occurs during PISA leads to enhanced phase separation relative to that achieved using solution‐cast molecularly‐dissolved copolymer chains., Polymerization‐induced self‐assembly enables the scalable synthesis of functional block copolymer nanoparticles with various morphologies. This versatile technique is exploited to prepare so‐called “high χ–low N” diblock copolymers that undergo nanoscale phase separation in the solid state to produce sub‐10 nm domains.

Particle sizes represent one of the key factors influencing the usability and specific targeting of nanoparticles in medical applications such as vectors for drug or gene therapy. A multi‐layered graph convolutional network combined with a fully connected neuronal network is presented for the prediction of the size of nanoparticles based only on the polymer structure, the degree of polymerization, and the formulation parameters. The model is capable of predicting particle sizes obtained by nanoprecipitation of different poly(methacrylates). This includes polymers the network has not been trained with, indicating the high potential for generalizability of the model. By utilizing this model, a significant amount of time and resources can be saved in formulation optimization without extensive primary testing of material properties., Utilizing a combination of different model structures and machine learning techniques, a model that is able to predict the size of polymeric nanoparticles based solemnly on the structure and preparation parameters is presented. The prediction achieves results with errors

PEG is the gold standard polymer for pharmaceutical applications, however it lacks degradability. Degradation under physiologically relevant pH as present in endolysosomes, cancerous and inflammatory tissues is crucial for many areas. The authors present anionic ring‐opening copolymerization of ethylene oxide with 3,4‐epoxy‐1‐butene (EPB) and subsequent modification to introduce acid‐degradable vinyl ether groups as well as methacrylate (MA) units, enabling radical cross‐linking. Copolymers with different molar ratios of EPB, molecular weights (M n) up to 10 000 g mol−1 and narrow dispersities (Đ, Responsive gels: P(EG‐co‐isoEPB)MA, a PEG copolymer with acidic degradability under physiologically relevant pH is employed for hydrogels. The attached methacrylate units enable radical cross‐linking to form protein‐loaded hydrogels. Both the P(EG‐co‐isoEPB)MA copolymer as well as the respective hydrogels show rapid and tailorable hydrolysis at physiologically relevant pH (pH 5–6), despite excellent storage stability at neutral pH (pH 7.4).

Cobaltocenium-containing polyelectrolyte block copolymer nanoparticles were prepared via polymerization-induced self-assembly (PISA) using aqueous dispersion RAFT polymerization. The cationic steric stabilizer was a macromolecular chain-transfer agent (macro-CTA) based on poly (2-cobaltocenium amidoethyl methacrylate chloride) (PCoAEMACl), and the core-forming block was poly(2-hydroxypropyl methacrylate) (PHPMA). Stable cationic spherical nanoparticles were formed in aqueous solution with low dispersity without adding any salts. The chain extension of macro-CTA with HPMA was efficient and fast. The effects of block copolymer compositions, solid content, charge density, and addition of salts were studied. It was found that the degree of polymerization of both the stabilizer PCoAEMACl and the core-forming PHPMA had a strong influence on the size of nanoparticles.

We report the synthesis of polystyrene‐block‐poly(dimethyl siloxane) (PS‐b‐PDMS) brush block copolymers (BBCPs) through sequential ROMP of norbornene‐modified macromonomers (‐NB) and explore the effect of side chain length (Nₛc) and total backbone degree of polymerization (Nbb) on the self‐assembly of lamellar morphologies. Group I (PS‐NB Mₙ = 2.9 kg/mol, PDMS‐NB Mₙ = 4.8 kg/mol) exhibits asymmetric side chains, while Group II (PS‐NB Mₙ = 4.7 kg/mol, PDMS‐NB Mₙ = 4.8 kg/mol) possess a more symmetric arrangement. Both families rapidly self‐assemble into well‐ordered lamellar morphologies with domain spacings (d₀) ranging from d₀ = 54 to 140 nm. The scaling relationship between d₀ and Nbb (d₀ ~Nbbᵅ) was determined as the measure of backbone flexibility. Exponents of α = 0.71 and α = 0.81 are observed for Groups I and II, respectively, indicating the BBCPs adopt an extended backbone conformation. The presence of a low Tg side chain such as PDMS increases apparent flexibility of the backbone. The interplay between contrasting characteristics of the side chains is discussed and reveals the importance of understanding the physical consequences of block architecture on controlling BBCP assembly. These findings provide necessary information for future investigations of complex phases and well‐defined nanostructures fabricated using the brush architecture. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2019, 57, 691–699

Polyphosphates (PPs) are of interest as temporary in situ setting embolic agents for which cohesive characteristics are vital. Trivalent ions Al3+ and Ga3+ were substituted into calcium PP up to 10 mol % for two PP chain lengths (degree of polymerization, Dp 200 and 9000) and the effect on the dissolution rate of the resulting coacervate was examined. High levels of trivalent ions were found to increase the dissolution rate, especially with aluminum (Al) where the coacervate with the greatest Al content (10 mol %) and larger Dp completely dissolved within the first few hours in tris(hydroxymethyl)aminomethane buffered saline. Conversely, small amounts of trivalent ions slowed the dissolution rate of the coacervates compared to those containing calcium only. The coacervate compositions determined to have the fastest and slowest ion release were evaluated for cohesion upon injection into a simulated blood vessel using a dual lumen needle. PPs with lower trivalent content had a higher coacervate yield overall, with 5% Ga and Dp 200 yielding the smallest proportion of coacervate particulates that could be implicated in unwanted distal embolization. However, further studies are required to evaluate the formation and duration of occlusions in vivo so that the PP composition can best be tailored to meet clinical requirements. © 2019 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 107B:2638-2648, 2019.

Multicolor emissive and responsive materials are highly attractive owing to their potential applications in various fields, and polymers are preferred for their good processability and high stability. Herein, we report a series of new polymers based on a methacrylate monomer containing a switchable boron chromophore. In spite of their unconjugated nature, interestingly, the homopolymers from this monomer display rare multicolor fluorescence in solution that is highly dependent on the degree of polymerization (DP). With an increasing DP, the local concentration of the chromophore increases, leading to a higher propensity for switching the blue-emitting tricoordinate boron chromophore to the red-emitting tetracoordinate one. The homopolymers also display temperature- and solvent-dependent emission color change. Furthermore, pure white-light emission could be achieved in various solvents by precisely tuning the homopolymer molecular weight, or in films/solid state by copolymerizing the emissive boron monomer with non-emissive monomers in an appropriate ratio.

This is the first study in which the effect of degree of polymerization (DP) (˂10 and ≥23) of inulin (6.00, 9.00, and 12.0/100 g) on main quality parameters (color, texture, water activity, sensory properties, and melting behavior) of compound chocolate's (CC) was investigated. According to the determined L* values, using inulin (12/100 g) with high DP resulted in more glossy samples (p < .05). Except ∆h value, the melt ing parameters of CC were not affected. However, the hardness of samples (391.9– 587.1 g) was determined in a wide range. The CC samples including inulin with higher DP had higher aw values (p < .05). According to the results of sensory analysis, using low DP inulin (

It is demonstrated that the degree of livingness (chain‐end fidelity) in RAFT polymerization for a given degree of polymerization can be markedly increased in miniemulsion polymerization relative to the corresponding homogeneous bulk system. Polymerization of styrene was conducted using a poly(methyl methacrylate) benzodithioate as macroRAFT agent in both miniemulsion and bulk. The substantially higher polymerization rate in miniemulsion, which is attributed to the segregation effect (compartmentalization) causing a reduction in the rate of bimolecular termination, makes it possible to reach a given degree of polymerization in a significantly shorter time than in the corresponding bulk system. As a consequence, fewer initiating radicals are required throughout the polymerization, leading to higher livingness in the more rapid miniemulsion system. It is demonstrated how this approach facilitates synthesis of high‐molecular‐weight block copolymers comprising slowly propagating monomers such as styrene and methacrylates. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019, 57, 1938–1946

Inhibition of target digestive enzymes is an accepted strategy to prevent diseases such as obesity and diabetes. Proanthocyanidins (PACs) are known for their ability to bind, inhibit, and precipitate enzymes, which makes them potential bioDrugs with an impact on the digestive process. PAC degree of polymerization (DP) is one of the structural features responsible for their differential inhibitory potency but the explanation for this phenomenon is still unclear. Pecan nut (Carya illinoinensis L.) kernels and nutshells are rich in oligomeric and polymeric PACs. We have used thiolysis and HPLC analyses to propose four theoretical model structures of PACs representative of four semipurified fractions obtained from pecan kernel and shell, which showed different inhibitory activity against intestinal lipases, amylases, and proteases. The noncovalent interactions between PACs and digestive enzymes were predicted by in silico methods through computational software. These observations are discussed in view of current literature on the biological effects of PACs with different DPs and allowed us to propose the hypothesis that "small oligomeric PACs could be digestive enzyme inhibitors due to their capacity to enter and bind the enzymes' specific cavities better than polymers and oligomers of medium and high molecular weight."; © 2018 Institute of Food Technologists®.

The irradiation of concentrated feeds of carbohydrates in alcoholic solution by high-frequency ultrasound (550 kHz) induces the formation of alkylpolyglycosides (APGs). This work is distinct from previous reports in that it does not involve any (bio)catalyst or activating agent, it takes place at only 40 °C, thus avoiding degradation of carbohydrates, and it selectively yields APGs with a degree of polymerization in a window of 2¿7, an important limitation of the popular Fischer glycosylation. This ultrasound-based technology proved successful with a range of different valuable carbohydrates and alkyl alcohols. The elucidation of the structure of all the produced glycosides strongly suggests that 1,6-anhydrosugars formed in situ are key intermediate species., Authors are grateful to the CNRS, the University of Poitiers, the Ministry of Research, the Région Nouvelle Aquitaine, the MINECO (contract nos. SAF2016‐76083‐R and CTQ2015‐64425‐C2‐1‐R), the Junta de Andalucía (contract no. FQM2012‐1467) and the European Community (FEDER) for their financial supports.

5-Hydroxymethylfurfural (HMF) is regarded as a thermal process contaminant in foods. Six flavan-3-ol fractions were isolated or semisynthesized from sorghum, cranberry and grape seed. Their unit compositions, interflavan linkages and degree of polymerization were characterized. The aim of this study was to investigate the effect of flavan-3-ols on the formation of HMF in chemical reaction models and fried potato chips.; Results: Results showed that all flavan-3-ols significantly mitigated the HMF formation at concentrations of 50, 100 and 200 µg mL-1 in the chemical model system, and the inhibition was positively related to dose. Using the food model, HMF content was reduced by about 50% when potato chips were soaked in an optimal concentration of 0.1 mg mL-1 flavan-3-ol solutions before frying. Based on the same mass concentration, B-type flavan-3-ols mitigated more HMF than A-type, and oligomeric proanthocyanidins had stronger inhibitory activity than polymers. At suitable addition levels (0.01-0.1 mg mL-1 ), the browning of auto-oxidized flavan-3-ols under high temperature compensated the anti-browning effect along with the supression of the Maillard reaction; therefore, the color of fried potato chips was not affected.; Conclusion: This study demonstrates that flavan-3-ols could be effective additives for reducing HMF levels in fried potato chips without changing sensory properties. © 2018 Society of Chemical Industry.; © 2018 Society of Chemical Industry.

Fully or partially charged oligosaccharide molecules play a key role in many areas of biology, where their fine structures are crucial in determining their functionality. However, the separation of specific charged oligosaccharides from similar moieties that typically coexist in extracted samples, even for those that are unbranched, and in cases where each saccharide moiety can only carry a single charge or not, is far from trivial. Typically such molecules are characterized by a degree of polymerization n and a number m (and distribution) of charged residues, and must be separated from a plethora of similar species possessing different combinations of n and m. Furthermore, the separation of the possible n!/m!(n-m)! isomers of each species of fixed n and m is a formidable challenge to analytical chemists. Herein, we report the results of molecular dynamics simulations that have been performed in order to calculate the free solution electrophoretic mobilities of galacturonides and charged oligosaccharides derived from digests of the important plant cell-wall polysaccharide pectin. The simulations are compared with an experiment and are found to correctly predict the loss of resolution of fully charged species above a critical degree of polymerization n and the ionic strength dependence of the electrophoretic mobilities of different partially charged oligosaccharides. It is expected that having a predictive tool for the calculation of the electrophoretic mobilities of differently charged oligosaccharide species in hand will allow experimental conditions that optimize the resolution of particular species to be ascertained and understood.

Aliphatic polyesters such as polylactides (PLAs) and other polylactones are thermoplastic, renewable and biocompatible polymers with high potentials to replace petro-chemical-based synthetic polymers. A benign route for synthesizing these polyesters is through the enzyme-catalyzed ring-opening polymerization (ROP) reaction; this type of enzymatic process is very sensitive to reaction conditions such as solvents, water content and temperature. This review systematically discusses the crucial roles of different solvents (such as solvent-free or in bulk, organic solvents, supercritical fluids, ionic liquids, and aqueous biphasic systems) on the degree of polymerization and polydispersity. In general, many studies suggest that hydrophobic organic solvents with minimum water contents lead to efficient enzymatic polymerization and subsequently high molecular weights of polyesters; the selection of solvents is also limited by the reaction temperature, e.g. the ROP of lactide is often conducted at above 100 °C, therefore, the solvent typically needs to have its boiling point above this temperature. The use of supercritical fluids could be limited by its scaling-up potential, while ionic liquids have exhibited many advantages include their low-volatility, high thermal stability, controllable enzyme-compatibility, and a wide range of choices. However, the fundamental and mechanistic understanding of the specific roles of ionic liquids in enzymatic ROP reactions is still lacking. Furthermore, the lipase specificity towards l- and d-lactide is also surveyed, followed by the discussion of engineered lipases with improved enantioselectivity and thermal stability. In addition, the preparation of polyester-derived materials such as polyester-grafted cellulose by the enzymatic ROP method is briefly reviewed.

Herein, cylindrical molecular bottlebrushes grafted with poly(2-oxazoline) (POx) as a shaped tunable uni-molecular nanoparticle were synthesized via the grafting-onto approach. First, poly(glycidyl methacrylate) (PGMA) backbones with azide pendant units were prepared via reversible addition fragmentation transfer (RAFT) polymerization followed by post-modification. The degree of polymerization (DP) of the backbones was tuned in a range from 20 to 800. Alkynyl-terminated POx side chains were synthesized by living cationic ring opening polymerization (LCROP) of 2-ethyl-2-oxazoline (EtOx) and 2-methyl-2-oxazoline (MeOx), respectively. The DP of side chains was varied between 20 and 100. Then, the copper-catalyzed azide-alkynyl cycloaddition (CuAAC) click chemistry was conducted with a feed ratio of [alkynyl]:[azide] = 1.2:1 to yield a series of brushes. Depending on the DP of side chains, the grafting density ranged between 47 and 85%. The resulting brushlike nanoparticles exhibited shapes of sphere, rod and worm. Aqueous solutions of PEtOx brushes demonstrated a thermoresponsive behavior as a function of the length of backbones and side chains. Surprisingly, it was found that the lower critical solution temperature of PEtOx brushes increased with a length increase of backbones. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017

This article reports a synthetic methodology for single step preparation of telechelic poly(disulfide)s (PDS) by step-growth polymerization between a di-thiol and a commercially available monomer 2,2′-dithiodipyridine in presence of a functional group appended pyridyl disulfide moiety as the “mono-functional impurity” (MFI). Redox-destructible well-defined segmented PDSs with functional chain terminal, predicted and tunable degree of polymerization and narrow polydispersity index (

For the first time, we combined orthogonal maleimide and thiol deprotections together with thiol-maleimide coupling to synthesize discrete oligomers/macromolecules on gram scale with molecular weight up to 27.4 kDa (128mer, 7.9 g) via iterative exponential growth strategy with degree of polymerization (DP) at 2^n-1. By using the same chemistry, a "readable" sequence-defined oligomer and a discrete cyclic topology were also created. Furthermore, uniform dendrons were fabricated via either sequential growth (DP =〖 2〗^n-1) or double exponential dendrimer growth approach (DP =2^(2^n )-1) with significantly accelerated growth rate. This work offered a versatile, efficient and metal-free platform for construction of discrete oligomers with vast designability and high growth rate, which would greatly facilitate sophisticated structure-property research as well as applications of precise polymer-based materials.

Three glucosamide-based polysiloxanes (GAPS) surfactants were prepared by amidation of gluconolactone with amino functional polysiloxanes synthesized by polymerization. GAPS were characterized by FT-IR, 1H NMR and 13C NMR. Surface activity and aggregation behavior in aqueous solution were studied by surface tension measurements, dynamic light scattering and transmission electron microscopy. GAPS can reduce the surface tension of water to 24 mN m−1 at concentration levels of 10−4 g mL−1 and self-assemble in water at room temperature to form spherical micelles with average diameters ranging from 30 to 1000 nm. The micelle diameter increases with increasing degree of polymerization.

A series of cationic diblock copolymers were synthesized via sequential anionic polymerization of 2-vinylpyridine and ethylene oxide and further quaternization of the resulting diblock copolymers with dimethyl sulfate. Diblock copolymers with a degree of polymerization (DP) of the cationic block equal to 40 and DP of the poly(ethylene oxide) (PEO) block equal to 45, 210 and 450, as well as a cationic homopolymer with DP = 40 (control), were adsorbed on the surface of anionic liposomes of 40–60 nm in diameter. The liposomes were constructed with egg lecithin admixed with 0.1 mole fraction of a doubly anionic lipid, cardiolipin. The liposome–polymer complexes were characterized using electrophoretic mobility measurements, dynamic light scattering, conductivity, fluorescence and UV spectroscopy, and differential scanning calorimetry. Adsorption of the polymers causes the liposomes to aggregate; the only exception is the diblock copolymer with DP of the PEO block of 450, which shows an aggregation-preventing effect. In all cases, the integrity of liposomes is retained upon their complexation with polymers. The diblock copolymer with a short PEO block induces clustering of anionic lipid in the outer leaflet of the membrane; this effect becomes less pronounced with increasing DP of the PEO block. The differences in behaviour of the diblock copolymers are explained in terms of copolymer cluster formation via hydrogen bonding between neighbouring PEO blocks. These observations are important for interpretation of biological effects produced by cationic polymers and selection of cationic polymers for biomedical applications. © 2017 Society of Chemical Industry

Liquid crystalline block copolymers (LCBCPs) are fascinating for their combining molecular level liquid crystalline orders and microphase separated multidomain morphologies. Here in this article, a series of PEG-containing side-chain discotic LCBCPs of PEG-b-Pm-n with variant spacer length m = 6, 10 and degree of polymerization (DP) of discotic LC block from n = 10 to 45, have been well-synthesized via reversible addition-fragmentation chain-transfer (RAFT) polymerization. The RAFT process mediated by macromolecular chain transfer agent (macroCTA) shows remarkable monomer concentration dependence. The influence of the introduced PEG block on the nano-scale microphase-segregation and mesophase organization is closely related to the side-chain triphenylene (TP) discogens stacking mode dependent on the spacer length. Wherein, the PEG-b-P6-n series with a six-methylene spacer exhibit consistent microphase separation with slightly disturbed yet ordered columnar structures. While for PEG-b-P10-n series with a longer ten-methylene spacer, the columnar organization in the copolymers is even improved in contrast with the low order of randomly TP stacking in their corresponding homopolymers. This work offers a viable and inspiring pathway for controlled synthesis of block copolymers with bulky side groups, as well as enhances in-depth understanding of the hierarchical superstructure organization in discotic units involved complex block copolymers. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017

A cholesteryloxyallene (1) bearing chiral cholesteryl pendant group was designed and synthesized. Living polymerization of this monomer with an allylnickel complex as a catalyst give poly(cholesteryloxyallene)s (poly-1ms) in high yields with controllable molecular weights and narrow molecular weight distributions. These polymers were found to possess a dynamic helical conformation with a preferred handedness in n-hexane as confirmed by circular dichroism and absorption spectra as well as optical ratios. The helical conformation of the polymers was revealed to stabilize as the number of repeat units increased until the degree of polymerization reached 100. The helical conformation of poly-1100 could be controlled by altering the temperature of solutions. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017, 55, 2227–2233

Cell-penetrating peptides are an important class of molecules with promising applications in bioactive cargo delivery. A diverse series of guanidinium-containing polymeric cell-penetrating peptide mimics (CPPMs) with varying backbone chemistries was synthesized and assessed for delivery of both GFP and fluorescently tagged siRNA. Specifically, we examined CPPMs based on norbornene, methacrylate, and styrene backbones to determine how backbone structure impacted internalization of these two cargoes. Either charge content or degree of polymerization was held constant at 20, with di-guanidinium norbornene molecules being polymerized to both 10 and 20 repeat units. Generally, homopolymer CPPMs delivered low amounts of siRNA into Jurkat T cells, with no apparent backbone dependence; however, by adding a short hydrophobic methyl methacrylate block to the guanidinium-rich methacrylate polymer, siRNA delivery to nearly the entire cell population was achieved. Protein internalization yielded similar results for most of the CPPMs, though the block polymer was unable to deliver proteins. In contrast, the styrene-based CPPM yielded the highest internalization for GFP (~40% of cells affected), showing that indeed backbone chemistry impacts protein delivery, specifically through the incorporation of an aromatic group. These results demonstrate that an understanding of how polymer structure affects cargo-dependent internalization is critical to designing new, more effective CPPMs.

The reactivity of synthetic glasses depends on their chemical compositions. In far from equilibrium dissolution experiments, the reactivity of Ca-rich glasses with compositions similar to blast-furnace slag is found to be much higher (up to ~60 wt.% after 7 days) compared to Si-rich glasses with compositions similar to type F fly ash (up to ~20 wt.% after 7 days). Isothermal calorimetry and TGA experiments conducted on model systems containing portlandite and calcite and on glass-blended Portland cement confirmed the higher reactivity of the Ca-rich glasses. The degree of glass reaction after 91 days ranged from 7 to 20 wt.%. The results showed also a higher reactivity of the glasses containing more aluminum (both for Ca-rich and Si-rich glasses) indicating that not only calcium but also aluminum acted rather as network modifier than as network former. The results confirm a strong dependence of the glass reactivity on the degree of polymerization of the glass network.

The molecular size distribution of maize starch nanoparticles (SNP) prepared by acid hydrolysis (3.16M H2SO4) and their amylase-resistant counterparts, before and after debranching, was investigated. The weight average molecular weight (Mw) and linear chain length distribution were determined by high-performance size-exclusion chromatography (HPSEC) and high-performance anion-exchange chromatography (HPAEC), respectively. The objective was to understand the role of amylose involvement in the formation of SNP showing different crystalline structures (A- and B-types). The HPSEC profiles of SNP before debranching from waxy, normal, and high-amylose maize starches showed broad monomodal peaks. Debranched SNP from waxy maize eluted in a single narrow peak, whereas those from nonwaxy starches showed a multimodal distribution. Similar trends were also observed for the chain length distribution patterns, for which the longest detectable chains (degree of polymerization [DP] 31) in waxy maize were significantly lo...

Macromolecular bioscience 2100158 (2021). doi:10.1002/mabi.202100158 special issue: "Hot Topic: Surfaces and Interfaces", Published by Wiley-VCH, Weinheim

The nucleating role of cellular membrane components, such as lipid moieties on amyloid beta (Aβ1-40 ) fibrillation, has been reported in recent years. The influence of conjugates fabricated from lipid anchors (cholesterol, diacylglycerol) and hydrophilic polymers on Aβ1-40 fibrillation is reported here, aiming to understand the impact of polymers cloud point temperature (Tcp ) and its hydrophobic tails on the amyloid fibrillation. Novel lipid-polymer conjugates, consisting of poly(oligo(ethylene glycol)m acrylates) and hydrophobic groups (diacylglyceryl-, cholesteryl-, octyl-, decyl-, hexadecyl-) as anchors are synthesized using reversible addition-fragmentation chain transfer (RAFT) polymerization, allowing to tune the hydrophilic-hydrophobic profile of the conjugates by varying both, the degree of polymerization (n) and number of ethylene glycol units (m) in their side chain. The impact of these conjugates on Aβ1-40 fibrillation is investigated via in vitro kinetic studies and transmission electron microscopy (TEM). Hydrophobic lipid-anchors are significantly delaying fibrillation (both lag- and half times), observing similar fibrillar structures via TEM when compared to native Aβ1-40 . Other hydrophobic end groups are also delaying fibrillation of Aβ1-40 , irrespective of their "n" and "m," whereas more hydrophilic polymers (both with longer ethylene glycol-sidechains, m = 3 for octyl, decyl and m = 5 for cholesterol) are only marginally inhibited fibrillation.

Polysialic acid (polySia), consisting of α-(2,8)-linked N-acetylneuraminic acid monomers plays a crucial role in many biological processes. This study presents a novel process for the production of endogenous polySia using Escherichia coli K1 in a disposable bag reactor with wave-induced mixing. Disposable bag reactors provide easy and fast production in terms of regulatory requirements as GMP, flexibility, and can easily be adjusted to larger production capacities not only by scale up but also by parallelization. Due to the poor oxygen transfer rate compared to a stirred tank reactor, pure oxygen was added during the cultivation to avoid oxygen limitation. During the exponential growth phase the growth rate was 0.61 h-1. Investigation of stress-related product release from the cell surface showed no significant differences between the disposable bag reactor with wave-induced mixing and the stirred tank reactor. After batch cultivation a cell dry weight of 6.8 g L-1 and a polySia concentration of 245 mg L-1 were reached. The total protein concentration in the supernatant was 132 mg L-1. After efficient and time-saving downstream processing characterization of the final product showed a protein content of below 0.04 mgprotein/gpolySia and a maximal chain length of ∼90 degree of polymerization.

In an effort to better understand and overcome biomass recalcitrance, six natural poplar variants were selected as the feedstock. Compositional analysis and physicochemical characterizations of these poplars were performed using different analytical techniques and the correlations between these physicochemical properties and enzymatic hydrolysis yield were investigated. Gel permeation chromatography (GPC) and 13C NMR were used to determine the degree of polymerization (DP) and crystallinity index (CrI) of cellulose, and the results along with the sugar release study indicated that cellulose DP likely played a more important role in enzymatic hydrolysis. Simons' stain revealed that accessible surface area of cellulose significantly varied among these variants from 17.3 to 33.2 mg/g biomass as reflected by dye adsorption, and cellulose accessibility was shown as one of the major factors governing substrates digestibility. HSQC and 31P NMR analysis detailed the structural features of isolated poplar lignin variants. Overall, cellulose relevant factors appeared to have a stronger correlation with glucose release, if any, than lignin structural features. Lignin structural features such as phenolic hydroxyl group and S/G ratio were found to have a more convincing impact on xylose release. Low lignin content, low cellulose DP and high cellulose accessibility generally favors enzymatic hydrolysis; however, recalcitrance cannot be simply judged on any solely substrate factor.

An organic polymer containing cyclobutanes and amides as backbones and pyridyl groups as sidearms was synthesized by single-crystal-to-single-crystal (SCSC) [2+2]-photopolymerization in the coordination polymers (CPs) of diene. The diene molecule was photo-inactive in its crystals and formed a triply intertwined 1D-helical CP with Cd(NO3)2 and Cu(NO3)2 salts. The 1D-CP was transformed into a coordination polymer of organic polymers containing threefold interpenetrated 3D-networks of CdSO4 topology through a [2+2]-reaction in SCSC manner upon irradiation. The organic polymer was separated from its CPs and found to have an unusually high degree of polymerization for this type of reaction. Furthermore, the organic polymer was amenable for N-alkylation reactions such as methylation, propylation, and decylation. The formate salts of the organic polymer and the methylated polymer were shown to form plastic films with a combination of properties such as high transparency, tensile strengths, gas permeability, thermal stability, water-resistance, and resistance to other organic solvents. The methylated polymer was also able to capture chromate ions and anionic dyes from aqueous solutions.

Well-defined magnetic polyelectrolytes with tetrachlorideferrate (FeCl4−) as counter ion are prepared. In this approach, norbornene-based monomer containing ammonium chloride group (TAENDI-Cl) is designed and synthesized. Well-defined magnetic polymers (Poly(TAENDI-FeCl4)) are obtained by ring-opening metathesis polymerization of TAENDI-Cl in the presence of Grubbs third generation catalyst followed by complexing with FeCl3. Magnetic block copolymers are thus prepared. Both the monomer and polymers are paramagnetic as measured by superconducting quantum interference device method. Studies show that the magnetic susceptibility increases with increasing degree of polymerization (DP) and reaches maximum at DP of 100, and then decreases with increasing DP. Block copolymer with lower FeCl4− content shows higher magnetic susceptibility. And, by introducing FeCl4−, the polymers show obviously magnetic responsive in solution, powder, and film which have potential applications in magnetic switching, transport, and separation.

Calcium silicate hydrate and its Al-substituted form synthesized by a hydrothermal process were investigated by X-ray diffraction, compositional analysis, and magic-angle spinning nuclear magnetic resonance (MAS NMR) spectroscopy, in order to determine the mechanism of Al and Na incorporation in the tobermorite structure with varying molar ratios of Ca/Si and Al/Si. At a high molar ratio of Ca/Si, the silicate chains of tobermorite are ruptured, the degree of polymerization of the silicate chains is lowered, and the high calcium concentration lowers the content of Na2O in the structure. Solid-state 29Si and 27Al MAS NMR spectroscopy confirm that all Al atoms were incorporated in the silicate chains of tobermorite. The tetrahedrally coordinated Al (Al(IV)) could either act as the bridging tetrahedron (QB2) for the dreierketten chain of tobermorite, or be present in Q3 sites that link two dreierketten chains together. Therefore, the degree of polymerization of the silicate chains of tobermorite is increased at high molar ratio of Al/Si. Furthermore, the greater charge deficit due to the replacement of Si4+ by Al3+ ions is compensated by increased adsorption or binding of Na+.

This research aimed to develop a suitable coating material for encapsulating a plant bioactive compound via spray drying. A suitable process for modifying the rheological property of konjac glucomannan (KGM) solution by enzymatic treatment was developed. A plant bioactive compound, andrographolide, was selected to use as core material. Mannanase (1500 units of enzyme) was used in the treatment of KGM solution. The concentration of KGM solution was varied from 9 to 18% (w/w). It was found that 12% (w/w) was the optimum KGM concentration that could be hydrolyzed to a viscosity of

Amphiphilic coil-rod-coil molecules, incorporating flexible and rigid blocks, have a strong affinity to self-organize into various supramolecular aggregates in bulk and in aqueous solutions. In this paper, we report the self-assembling behavior of amphiphilic coil-rod-coil molecular isomers. These molecules consist of biphenyl and phenyl units connected together with ether bonds as the rod segment, and poly (ethylene oxide)s (PEO) with a degree of polymerization (DP) of 7 and 12 as the flexible chains. Their aggregation behavior was investigated by differential scanning calorimetry (DSC), thermal optical polarized microscopy (POM), small-angle X-ray scattering (SAXS) spectroscopy, and transmission electron microscopy (TEM). The results imply that the molecular structure of the rod building block and the length of the PEO chains dramatically influence the creation of supramolecular aggregates in bulk and in aqueous solutions. In bulk state, these molecules self-organize into a hexagonal perforated lamellar and an oblique columnar structure, respectively, depending on the sequence of the rod building block. In aqueous solution, the molecule with a linear rod segment self-assembles into sheet-like nanoribbons. Onthe other hand, its isomer, with a rod building block substituted at meta-position of phenyl group, self-organizes into nanofibers. This is achieved through the control of the non-covalent interactions of the rod building blocks.

A series of thermoresponsive polypeptides bearing 1-butyl, 1-hexyl, or 1-dodecyl side-chains (i.e., 6a-6c) were synthesized by copper-mediated 1,3-dipolar cycloaddition with high grafting efficiency (>95%) between side-chain “clickable” polypeptide, namely poly(γ-4-(propargoxycarbonyl)benzyl-L-glutamate) (5) and 1-azidoalkanes. 5 with different degree of polymerization (DP = 48–86) were prepared from triethylamine initiated ring-opening polymerization of γ-4-(propargoxycarbonyl)benzyl-L-glutamic acid based N-carboxyanhydride (4). 1H NMR, FTIR, and GPC results revealed the successful preparation of the resulting polypeptides. 6a-6c showed reversible UCST-type phase behaviors in methanol, ethanol, and ethanol/water solvent mixtures depending on the polymer main-chain length, alkyl side-chain length, weight percentage of ethanol (fw) in the binary solvent, and so forth. FTIR analysis revealed the presence of the van der Waals interaction between the alkyl pendants of polypeptides and alkyl groups of alcoholic solvents. Variable-temperature UV-vis spectroscopy revealed that the UCST-type phase transition temperature (Tpt) increased as polymer main-chain length or concentration increased. In ethanol/water solvent mixtures, polypeptide with short alkyl pendant (i.e., 1-butyl group) and short main-chain length (DP = 41) showed the widest fw range and Tpts in the range of 61.0–71.1 °C. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016, 54, 3425–3435

Genipin is an ideal cross-linking agent in biomedical applications, which can undergo ring-opening polymerization in alkaline condition. The polygenipin can create short-range and long-range intermolecular cross-linking between protein chains. In this article, the polygenipin with different degree of polymerization was successfully prepared and used to fix gelatin composite materials. The short-range and long-range cross-linking effects of polygenipin were systematically studied. The results show that the composite materials present porous structure with tunable pore sizes in the gel state, which can be easily controlled by adjusting the degree of polymerization of polygenipin. Long-range cross-linking can increase the pore size of the gel. However, during the drying process, the composite films cross-linked by polygenipin with higher degree of polymerization shrank to smaller size to create more compact structure, resulting in the improvement of water resistance properties, thermal stability, tensile strength, and darker color for the composite films. It is interesting that the composite films can partly swell to the original gel structure when in contact with water and saturated water vapor. All the composite films have excellent barrier properties against UV light. However, the compatibility of gelatin and polygenipin is reduced when the degree of polymerization of polygenipin increases to a certain extent, which will result in the formation of phase separation structure. The obtained composite films are ideal candidates for food and pharmaceutical packaging materials. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 104A: 2712-2722, 2016.

Synthesis of calcium silicate hydrate (C-S-H) was conducted over the range of 50 degrees C-90 degrees C and C/S ratio of 0.86-2.14 in the highly alkaline Na2O-CaO-SiO2-H2O system for silicon utilization in high alumina fly ash. Structural change in C-S-H formed in the highly alkaline system was investigated using XRD and Si-29 MAS NMR spectra. X-ray photoelectron spectroscopy was used to confirm the amount of sodium ions in C-S-H. Conversion of Si may reach 99% under optimum conditions. A higher degree of polymerization of silicate was obtained at lower temperature and C/S ratio. Na+ was confirmed to exist as Na-OSi and Na-OH. The amount of Na+ is the least at C/S ratio of 1.43, which conform to the prediction of topological constraint theory. High Ca/Si ratio leads to the increasing in Na+ combined in the interlayer. Increasing in the Na+ concentration in the system also increases the amount of Na+ combined in the interlayer and reduces the polymerization. Ion exchange was proven to be an effective way to remove Na+ combined in the interlayer of C-S-H.

In order to construct unique polypeptide architectures, a novel telechelic-type initiator with two leucine ethyl ester units is designed for chemoenzymatic polymerization. Glycine or alanine ethyl ester is chemoenzymatically polymerized using papain in the presence of the initiator, and the propagation occurs at each leucine ethyl ester unit to produce the telechelic polypeptide. The formation of the telechelic polypeptides is confirmed by (1) H NMR and MALDI-TOF mass spectroscopies. It is revealed by AFM observation that long nanofibrils are formed from the telechelic polyalanine, whereas a conventional linear polyalanine with a similar degree of polymerization shows granule-like structures. The telechelic polyglycine and polyalanine show the crystalline structures of Polyglycine II and antiparallel β-sheet, respectively. It is demonstrated that this method to synthesize telechelic-type polypeptides potentially opens up a pathway to construct novel hierarchical structures by self-assembly.