Search

Your search keyword '"Williams, Rhodri"' showing total 373 results
Start Over Author "Williams, Rhodri"
373 results on '"Williams, Rhodri"'

8. Methanoanthracene-based polymers of intrinsic microporosity for membrane applications

Author

Williams, Rhodri John, McKeown, Neil, and Cowley, Michael

Subjects
methanoanthracene, methanopentacene, benzomethanoanthracene, gas separation membranes, methano-bridged units
Abstract

Polymers were synthesised containing the methanoanthracene (MA), methanopentacene (MP) and benzomethanoanthracene (BzMA) units to investigate their properties as gas separation membranes. For each monomer type, polymers were successfully synthesised using Tröger’s base (TB) chemistry and cast as free standing films from low-boiling point solvents. Gas permeability tests revealed high selectivities for most of the technologically significant gas pairs. Most interestingly, MA/dimethylethanoanthracene co-polymer, MP-TB and BzMT-TB polymers all show a high degree of selectivity in the separation of a number of technologically significant gas pairs when compared to other state-of-the-art polymers. In particular MP-TB has very high selectivity for the N2/O2 gas pair. Synthetic routes to MP-TB and BzMA-TB involve fewer steps and are significantly cheaper to implement compared to other state of the art TB polymers and high performance PIMs that provide data above the Robeson upper bounds due to their high permeability and selectivity. Co-polymers of MA were synthesised in 1:1, 4:1 and 9:1 ratios. Gas permeability data demonstrated that properties correlate with the monomer composition. Results indicate that inclusion of methano-bridged units into the polymers increased the rigidity of polymer chains, leading to smaller pore widths and improved selectivities compared to polymers such made from more flexible structural units. The first chapter of this thesis introduces the concepts of microporosity, permeability and membrane separation, and describes a number of polymers that have demonstrated properties of interest for separating gas mixtures. Chapter two describes the synthesis and gas permeability data of MA-TB polymer and a series of copolymers incorporating MA. Chapter 3 describes the synthesis of polymers containing the MP structural unit and describes the performance of MP-TB as a membrane for gas separation. Chapter 4 describes a number of polymers synthesised using the BzMA structural unit and chapter 5 reports the synthesis of a number of larger units derived from BzMA including benzomethanotetracene, benzomethanopentacene and dibenzomethanopentacene. Permeability data for TB polymers synthesised from BzMA-type monomers is reported in these chapters.

Published
2017

32. Author Correction: Hydrophilic microporous membranes for selective ion separation and flow-battery energy storage

Author

Tan, Rui, Wang, Anqi, Malpass-Evans, Richard, Williams, Rhodri, Zhao, Evan Wenbo, Liu, Tao, Ye, Chunchun, Zhou, Xiaoqun, Darwich, Barbara Primera, Fan, Zhiyu, Turcani, Lukas, Jackson, Edward, Chen, Linjiang, Chong, Samantha Y., Li, Tao, Jelfs, Kim E., Cooper, Andrew I., Brandon, Nigel P., Grey, Clare P., McKeown, Neil B., and Song, Qilei

Published
2020
Full Text
View/download PDF

45. Does Medial Overhang of the Greater Trochanter Influence Femoral Stem Position During Cemented Hip Arthroplasty? A Retrospective Radiological Review

Author

Bayley, Morgan, Cnudde, Peter, Adds, Phillip J, Jones, Stephen, and Williams, Rhodri L

Subjects
musculoskeletal diseases, Orthopedics, anatomy, total hip arthroplasty, surgical procedures, operative, x-ray, Radiology, musculoskeletal system, greater trochanter
Abstract

Purpose\ud We investigate the effect that variation in the anatomy of the greater trochanter (GT), in particular the medial overhang, can have on femoral stem alignment in total hip arthroplasty (THA).\ud \ud Methods\ud Pre- and post-operative anteroposterior pelvic radiographs of 576 consecutive patients undergoing THA were retrospectively analysed. Medial overhang of the GT relative to the lateral femur diaphysis was measured. The femoral morphology was classified according to Dorr classification. The alignment of the femoral stem axes on post-operative radiographs was recorded.\ud \ud Results\ud Following exclusions, 500 THAs performed by six surgeons all using the same cemented polish tapered stems were analysed: 320 THAs were performed via the posterior-lateral approach and 180 via the direct-lateral approach. Mean stem varus was 0.53° (range: -7 to 7°). Mean medial overhang was 21 mm (range: 8-43 mm). An overhang of 30 mm had a mean varus of 2.33°. Those with an overhang of 30 mm. One-way analysis of variance comparison of these groups returned a p-value of 30 mm of overhang).\ud \ud Conclusions\ud Scrutiny of pre-operative radiographs to determine high-risk patients is important, and we propose a classification system of GT anatomy to aid assessment.

Published
2020

46. Preventing the coffee-ring effect and aggregate sedimentation by in situ gelation of monodisperse materials† †Electronic supplementary information (ESI) available. See DOI: 10.1039/c8sc03302a

Author

Li, Huaiguang, Buesen, Darren, Williams, Rhodri, Henig, Joerg, Stapf, Stefanie, Mukherjee, Kallol, Freier, Erik, Lubitz, Wolfgang, Winkler, Martin, Happe, Thomas, and Plumeré, Nicolas

Subjects
Chemistry
Abstract

Microscale uniformity and long-range cohesion in multi-functional films assembled through drop-casting is realized by in situ gelation of monodisperse building blocks., Drop-casting and inkjet printing are virtually the most versatile and cost-effective methods for depositing active materials on surfaces. However, drawbacks associated with the coffee-ring effect, as well as uncontrolled aggregation of the coating materials, have impeded the use of these methods for applications requiring high control of film properties. We now report on a simple method based on covalent cross-linking of monodisperse materials that enables the formation of thin films with homogeneous thicknesses and macroscale cohesion. The coffee-ring effect is impeded by triggering gelation of the coating materials via a thioacetate–disulfide transition which counterbalances the capillary forces induced by evaporation. Aggregates are prevented by monodisperse building blocks that ensure that the resulting gel resists sedimentation until complete droplet drying. This combined strategy yields an unprecedented level of homogeneity in the resulting film thickness in the 100 nm to 10 μm range. Moreover, macroscale cohesion is preserved as evidenced by the long-range charge transfer within the matrix. We highlight the impact of this method with bioelectrocatalysts for H2 and NADPH oxidation. Peak catalytic performances are reached at about 10-fold lower catalyst loading compared to conventional approaches owing to the high control on film cohesion and thickness homogeneity, thus setting new benchmarks in catalyst utilization.

Published
2018

Catalog

Books, media, physical & digital resources
See catalog results