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47 items found (0 items not approved), displaying 1 to 10.[First/Prev] 1, 2, 3, 4, 5 [Next/Last]

Instruments / Technical Area	Publication Details	Published
B21-High Throughput SAXS	Transparent diblock copolymer nanoparticle dispersions via efficient RAFT emulsion polymerisation in ionic liquid Anisha Patel , Georgia L. Maitland , Evelina Liarou , Paul D. Topham , Matthew J. Derry Polymer Chemistry 117 DOI: 10.1039/D5PY00076A Diamond Proposal Number(s): [39167] Open Access Show Abstract ▼ Abstract: We report the first reversible addition–fragmentation chain transfer polymerisation-induced self-assembly (RAFT-PISA) in ionic liquid (IL) that proceeds under emulsion conditions. Moreover, this formulation exploits refractive index contrast matching to generate highly transparent nanoparticle dispersions. Specifically, 1-ethyl-3-methyl-imidazolium ethylsulfate, [EMIM][EtOSO3], was used as the solvent for the chain extension of poly(2-hydroxyethyl methacrylate) (PHEMA) macromolecular chain transfer agents (macro-CTAs) using n-butyl methacrylate (BuMA) via RAFT emulsion polymerisation. Two series of PHEMAx-b-PBuMAy diblock copolymers with target PBuMA degrees of polymerisation (DPs) varying from 50 to 1000 were synthesised using either a PHEMA21 or PHEMA77 macro-CTA. All resulting nanoparticle dispersions yielded highly transparent dispersions, even when nanoparticle diameters exceeded 100 nm, due to the closely matched refractive index values of the [EMIM][EtOSO3] solvent and PBuMA nanoparticle core. Detailed analysis using small-angle X-ray scattering (SAXS) and transmission electron microscopy (TEM) confirmed the presence of spherical nanoparticles. Furthermore, the synthesis of PHEMA-b-PBuMA via this new PISA formulation was directly compared to equivalent block copolymer syntheses conducted in N,N-dimethylformamide (DMF) or ethanol/water mixtures. It was found that syntheses conducted in [EMIM][EtOSO3] resulted in the highest monomer conversions (up to >99%) and lowest dispersity (ĐM) values (as low as 1.16) in the shortest reaction times (2 hours) compared to the other solvent systems. This work demonstrates the use of ILs as a more sustainable and effective solvent for RAFT–PISA via the development of the first emulsion PISA formulation in IL.	May 2025
B21-High Throughput SAXS	Temperature- and time-dependent evolution of hydrogel network formed by thermoresponsive BCACB pentablock terpolymers: effect of composition Shaobai Wang , Theoni K. Georgiou Polymer 5 DOI: 10.1016/j.polymer.2025.128426 Diamond Proposal Number(s): [38094] Open Access Show Abstract ▼ Abstract: Three thermoresponsive BCACB pentablock terpolymers, in which A, B, and C blocks were composed of hydrophilic oligo(ethylene glycol) methyl ether methacrylate (average molar mass = 300 g/mol, OEGMA300), hydrophobic n-butyl methacrylate (BuMA), and less-hydrophilic di(ethylene glycol) methyl ether methacrylate (DEGMA), respectively, were synthesised via one-pot group transfer polymerisation (GTP) with varied chemical compositions. In addition to the thermoresponsive behaviour, a time-dependent evolution was also observed in both microscopic structure and macroscopic performance of the thermo-induced hydrogels formed by these terpolymers. Combined analysis using time-resolved small angle X-ray scattering (TR-SAXS) and rheometry reveals that achieving a balanced ratio of hydrophobic and hydrophilic content is critical for configuring hydrogel networks with optimal performance and stability. Specifically, an excessive hydrophobic content leads to a gradual loss of network storage modulus (G’) over time, while an overwhelming hydrophilic content diminishes the formation of stable elastic-active intermicellar correlations, resulting in the lowest G’.	Apr 2025
I22-Small angle scattering & Diffraction	Structure-property behavior of hydroxyl-terminated polybutadiene-based urethanes additionally cross-linked using sustainable biosourced rosin esters Aran Guner , Frank Lee , Daniel W. Lester , James S. Town , Steven Huband , Daniel Jubb , Ken Lewtas , Tony Mcnally Acs Applied Polymer Materials 1 DOI: 10.1021/acsapm.5c00220 Diamond Proposal Number(s): [34844] Open Access Show Abstract ▼ Abstract: Hydroxyl-terminated polybutadiene (HTPB) particularly when cross-linked with a diisocyanate is a very versatile elastomer having excellent mechanical and low temperature properties suitable for applications as diverse as binders in rocket propellants to surface coatings. These properties can be tailored further by the inclusion of a plasticizer, e.g., octadecyl adipate, but there are many technical challenges remaining around the use of such plasticizers, including migration from and miscibility with HTPB, together with the problem that such plasticizers are synthesized from non-renewable feedstocks. To address these limitations, rosin and functional rosin esters, sourced from pine trees, were blended with HTPB at loadings up to 20 wt % prior to cross-linking with toluene diisocyanate. All rosin esters studied were shown to be fully miscible with HTPB; a single glass transition temperature (Tg) was measured for all HTPB/rosin ester blends slightly above the Tg (−79 °C) of HTPB and well below that of the rosin esters (38–58 °C). Simultaneous wide-angle X-ray scattering (WAXS) and small-angle X-ray scattering (SAXS) measurements confirmed that there was no phase separation between the HTPB and rosin esters when blended. From increases in interdomain sizes, measured from X-ray scattering experiments on postcured samples, only the functional rosin ester (T3) takes part in the cross-linking reaction. Consequently, for the HTPB modified with T3 at 10 wt %, the elongation at break (ε) increased from 275% for unmodified HTPB to 600% and critically without a decrease in ultimate tensile strength (σ). For 20 wt % T3, ε increased to 1200%, and the material displayed strain-hardening behavior. The mechanical properties of HTPB can be tailored using functional rosin esters to alter the diisocyanate cross-linking reaction of the rubber.	Apr 2025
I22-Small angle scattering & Diffraction	Investigation of the degradation behaviour of poly-L-lactic acid braided stents under real-time and accelerated conditions Agnese Lucchetti , Flavia Caronna , Lison Rocher , Karl Joyce , Martin Fawdry , Olena Kudina , William Ronan , Thomas Gries , Ted J. Vaughan Polymer Testing 141 DOI: 10.1016/j.polymertesting.2024.108632 Diamond Proposal Number(s): [29651] Open Access Show Abstract ▼ Abstract: Degradation tests are a key step in the development of a bioresorbable stent. The present study focused on the degradation of bioresorbable stents made from PLLA filaments, and examined the variation of the physical, thermal, and mechanical properties of the material and the devices under both real-time and accelerated degradation conditions. Results showed that the undegraded filaments were highly crystalline and composed by both and crystalline phases, induced by both the melt spinning and heat treatment processes. The latter was shown to have an important influence on the further formation of crystalline phase and therefore crystalline structure perfectioning. Real-time degradation tests showed that the devices maintained structural stability for up to a year, meeting the required 6-month degradation period for vascular stents. Degradation was shown to primarily affect the crystalline regions, and to cause a gradual loss of material ductility before any mass loss or decrease in crystallinity. In turn, a constant decrease of molecular weight was observed, with stent failure occurring around day 389 due to a drop in molecular weight below 10,000 g/mol. Accelerated degradation tests mirrored real-time results until mass loss began. Subsequently a slower molecular weight decrease was observed, with an increase and subsequent decrease of material crystallinity. The consistency of the data obtained between real-time and accelerated degradation before mass loss confirmed the possibility to gain insights into real-time degradation through an accelerated protocol. However, attention must be paid to the initial molecular weight of the material, which has been shown to highly influence the acceleration rate. This study provides a wide range of experimental data both on the real-time and thermally accelerated degradation behaviour of PLLA braided stents that can be used as benchmark for further studies in the field.	Dec 2024
I09-Surface and Interface Structural Analysis	Interaction of boron-based cross-linkers with polymer binders for silicon anodes in lithium-ion batteries Tamara Patranika , Katharina Märker , Subhradip Paul , Andrew J. Naylor , Jonas Mindemark , Kristina Edström , Guiomar Hernández Acs Applied Polymer Materials 6 DOI: 10.1021/acsapm.4c01523 Diamond Proposal Number(s): [33024] Open Access Show Abstract ▼ Abstract: Intrinsic self-healing chemistries based on dynamic bonds have been shown to solve many issues in advanced applications, not the least batteries. Herein, we investigate the interactions within a polymer system containing dynamic covalent bonds as cross-linkers and their role when they are used as binders in silicon electrodes. We introduce 1,4-benzenediboronic acid (BDBA) as a cross-linking agent forming boronic ester groups and sodium tetraborate (borax) forming borate ester bonds with poly(vinyl alcohol) (PVA). Silicon electrodes with the cross-linked binders show improved electrochemical performance with a capacity of 1500 mA h g–1 after 200 cycles compared to PVA alone featuring 1000 mA h g–1. In contrast, another hydroxyl-containing polymer, carboxymethyl cellulose, able to form the same cross-linking functionalities, showed poorer performance with the addition of BDBA. The choice of polymer and cross-linker not only impacted the cell performance but also the electrode fabrication and morphology. The presence of cross-linkers decreased the electrode cracking of the pristine and cycled electrodes while having little effect on the solid electrolyte interphase composition. Hence, the properties of the polymeric binder system as a whole and the electrode manufacturing process have a significant impact on the cell performance. Solid-state NMR is shown to be a powerful technique to investigate the interaction between the different components and to confirm the formation of boronic ester bonds via the hydroxyl groups of PVA. Furthermore, the presence of silicon particles changes the chemical environment of the boron in BDBA favoring the formation of borate species, which are not present with PVA only, indicating interactions between BDBA and the silicon particles. Hence, PVA in combination with the boron-based cross-linkers, BDBA and borax, provide higher capacity and cycling stability than PVA alone, showing a promising approach to overcome the challenges of silicon anodes using binders with dynamic covalent bonds.	Oct 2024
B21-High Throughput SAXS	Metal-free ring-opening polymerization for the synthesis of biocompatible star-shaped block copolymers with controllable architecture Wanwanut Chueasupcharoen , Puttinan Meepowpan , Kiattikhun Manokruang , Montira Sriyai , Chawan Manaspon , Brian J. Tighe , Matthew J. Derry , Paul D. Topham , Winita Punyodom European Polymer Journal 8 DOI: 10.1016/j.eurpolymj.2024.113471 Diamond Proposal Number(s): [37105] Show Abstract ▼ Abstract: Star-shaped block copolymers (SBCs) have sparked interest as efficient cargo carriers due to their high loading capacity, decreased burst effects through sustained release, and maintained stability in dilute aqueous solution. Despite these advantages, the practical usage of SBCs is hindered by their challenging synthesis processes that often utilize metal-based catalysts at high temperatures. Herein we report the tailored synthesis of 3-, 4-, and 6-arm polycaprolactone-b-poly(ethylene glycol), PCL-b-PEG, SBCs using diphenyl phosphate as a friendlier, more sustainable non-metallic catalyst. Nuclear magnetic resonance (NMR) analysis confirms the molecular architecture of SBCs and gel permeation chromatography (GPC) is used to elucidate trends in molar mass when the number of arms within the SBCs is tuned, while dynamic light scattering (DLS) and small-angle X-ray scattering (SAXS) studies provide insights into aggregation behavior. Critical aggregation concentration (CAC) values, as measured by fluorescence spectroscopy, demonstrated that the 4-arm and 6-arm SBCs have greater stability than the 3-arm SBC. Biocompatibility assessment indicated minimal cytotoxicity of the nanoaggregates, even at high concentration, making these PCL-b-PEG SBCs potentially safe and sustainable vehicles for biomedical release applications.	Sep 2024
B21-High Throughput SAXS	Cross-link of telechelic diacrylate polyethylene-glycol in peptide-based Fmoc-FF hydrogel matrices Elisabetta Rosa , Paolo Pellegrino , Mariafrancesca Cascione , Rosaria Rinaldi , Eliana Gianolio , Charlotte J. C. Edwards-Gayle , Ian W. Hamley , Giancarlo Morelli , Antonella Accardo , Carlo Diaferia Acs Applied Polymer Materials DOI: 10.1021/acsapm.4c01059 Diamond Proposal Number(s): [26698] Show Abstract ▼ Abstract: Hydrogels (HGs) with enhanced structural and mechanical properties can be generated by combining two or more different building blocks in the same matrix. It has been widely demonstrated that the addition of peptides, proteins, sugars, or polymers to the low molecular weight hydrogelator Fmoc-FF [(fluorenyl methyloxycarbonyl)-diphenylalanine] can significantly modify the chemical and structural features of the resulting HGs. In this context, the formulation of multicomponent HGs has been previously described, in which Fmoc-FF is mixed with telechelic diacrylate α-/ω-substituted polyethylene-glycol derivatives (PEGDAs) with a molecular weight of 575 (PEGDA1) or 250 Da (PEGDA2). Here, we investigate the possibility to generate Fmoc-FF-based interpenetrated networks performing the cross-link reaction of PEGDA monomers in supramolecular peptide hydrogels. This approach can allow the modulation of the final properties of the material, in terms of water behavior, topography, and rigidity. The results indicate that the polymerization time, the polymer length, and the Fmoc-FF/PEGDA ratio play a crucial role in the chemistry of the materials and, consequently, of their potential application.	Jun 2024
B21-High Throughput SAXS	Effect of steam sterilisation on physico-chemical properties of antibacterial covalently cross-linked ε-polylysine/hyaluronic acid hydrogels Artemijs Sceglovs , Jacek K. Wychowaniec , Ingus Skadins , Aigars Reinis , Charlotte Edwards-Gayle , Matteo D'Este , Kristine Salma-Ancane Carbohydrate Polymer Technologies And Applications 6 DOI: 10.1016/j.carpta.2023.100363 Diamond Proposal Number(s): [29767] Open Access Show Abstract ▼ Abstract: Sterilisation of implantable biomaterials such as hydrogels remains a key step towards their clinical translation. Standard sterilisation methods can significantly alter hydrogels' physicochemical and biological performance. Previously, we developed composite hydrogels based on ε-polylysine (ε-PL) and hyaluronic acid (HA). The developed hydrogels demonstrated promising antibacterial activity and in vitro cell viability and their variable properties depending on the chosen ε-PL to HA ratio. In this study, we fabricated a series of chemically cross-linked ԑ-PL/HA hydrogels with expanded ԑ-PL to HA mass ratios. Using small-angle X-ray scattering (SAXS), we unravelled the topological differences between physically and chemically crosslinked hydrogels. We then selected the chemically crosslinked hydrogel ԑ-PL/HA series of 60:40 wt%, 70:30 wt%, and 80:20 wt% ratios, with similar network topologies, to evaluate the impact of steam sterilisation on their physicochemical and viscoelastic properties. The antibacterial activity of the sterilized hydrogels was also evaluated against Gram-negative and Gram-positive bacteria. Our results showed that steam sterilisation minimally affects structure and physicochemical properties of ԑ-PL/HA hydrogels. Furthermore, the developed hydrogel ԑ-PL/HA series of 60:40 wt%, 70:30 wt%, and 80:20 wt% ratios showed pronounced antibacterial activity against Gram-negative and Gram-positive pathogenic bacteria. We expect our results will contribute to the growing understanding of using sterilisation methods for antibacterial hydrogels that have the potential for wider tissue engineering applications.	Dec 2023
I22-Small angle scattering & Diffraction	Linking processing, microstructure and mechanical properties of expanded PLLA tubes for bioresorbable stent applications Lison Rocher , Jude Cameron , Jordan Barr , Brian Dillon , Alex B. Lennon , Gary H. Menary European Polymer Journal 35 DOI: 10.1016/j.eurpolymj.2023.112205 Diamond Proposal Number(s): [29651] Open Access Show Abstract ▼ Abstract: Bioresorbable poly-L-lactide (PLLA) stents have the potential to fully dissolve after treating injured arteries, leaving nothing behind. However, the manufacturing process for bioresorbable stents (BRS) needs further refinement to eventually replace current permanent stents. This study investigates the effect of radial and biaxial expansion procedures on the microstructure and mechanical properties of PLLA expanded tubes using microfocus small-angle X-ray scattering (WAXS) and multi-directional tensile tests. A complex microstructure with an orientation gradient across the thickness of the tube wall was observed and linked to the strain history experienced during processing. Correlations between the stretch ratios applied and the mechanical properties of the PLLA tubes were also noted and discussed in relation to stent application.	Jun 2023
B21-High Throughput SAXS	Influence of polymer molar mass and mixture stoichiometry on polyelectrolyte complexes of poly(l-arginine) and Poly(l-glutamic acid) Valeria Castelletto , Lucas De Mello , Foteini Arfara , Hermis Iatrou , Jani Seitsonen , Ian W. Hamley Polymer 3 DOI: 10.1016/j.polymer.2022.125497 Diamond Proposal Number(s): [29895] Open Access Show Abstract ▼ Abstract: Poly(l-arginine) (PARG) and poly(l-glutamic acid) (PLGA) homopolypeptides were custom synthesized by precision N-carboxyanhydride ring-opening polymerization methods with two molar masses, matched for pairs of cationic and anionic polypeptides (degrees of polymerization n = 100 and n = 500). The conformations of the homopolypeptides were probed using circular dichroism (CD) and FTIR spectroscopy which showed the presence of mainly polyproline II (PPII) conformation. Small-angle X-ray scattering (SAXS) showed concentration-dependent polyelectrolyte peaks and form factor with high q scaling due to the excluded volume behaviour of the wormlike chains. We then examined polyelectrolyte complexation in mixtures of pairs of PARG and PLGA polypeptides with matched molar masses. Precipitation was generally observed and the structures of precipitates, supernatant and resuspended precipitates were investigated using CD, SAXS and cryo-TEM. These revealed that, contrary to prior suggestions in the literature, the precipitates contain mostly polypeptides in a PPII-like conformation, and there is only a minimal β-sheet content (which is enhanced upon drying the sample during preparation for certain measurements). The precipitates have a fractal-like structure as revealed by cryo-TEM and SAXS. Our findings on the structure of polypeptide complex precipitates contribute to the understanding of phase separation of polyelectrolyte complexes and coacervation and may shed light on the formation of inter-cellular bodies of proteins and peptides such as Lewy and other inclusion bodies.	Nov 2022

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