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Development of a radical polymerization algorithm for molecular dynamics simulations of antifreezing hydrogels with double-network structures

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npj Computational Materials 2023年第1期9卷 204-213页

作者： Yonglan Liu Dong Zhang Yijing Tang Xiong Gong Jie Zheng Department of Chemical Biomolecularand Corrosion EngineeringThe University of AkronAkronOHUSA School of Polymer Science and Polymer Engineering The University of AkronAkronOHUSA

The development and understanding of antifreezing hydrogels are crucial both in principle and practice for the design and delivery of new *** current antifreezing mechanisms in hydrogels are almost exclusively derived from their incorporation of antifreezing additives,rather than from the inherent properties of the polymers ***,developing a computational model for the independent yet interconnected double-network(DN)structures in hydrogels has proven to be an exceptionally difficult ***,we develop a multiscale simulation platform,integrating‘random walk reactive polymerization’(RWRP)with molecular dynamics(MD)simulations,to computationally construct a physically-chemically linked PVA/PHEAA DN hydrogels from monomers that mimic a radical polymerization and to investigate water structures,dynamics,and interactions confined in PVA/PHEAA hydrogels with various water contents and temperatures,aiming to uncover antifreezing mechanism at atomic *** simulation results indicate that the antifreezing property of PVA/PHEAA hydrogels arises from a combination of intrinsic,strong water-binding networks and crosslinkers and tightly crosslinked and interpenetrating double-network structures,both of which enhance polymer-water interactions for competitively inhibiting ice nucleation and *** computational findings provide atomic-level insights into the interplay between polymers and water molecules in hydrogels,which may determine their resistance to freezing.

关键词： freezing polymerization hydrogel

Challenges and opportunities:a hopeful future of polymer rheology in China

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Science China Chemistry 2010年第1期53卷 151-156页

作者： WANG ShiQing Department of Polymer Science,University of akron,akron,Ohio,USA Department of Polymer Science University of Akron Akron USA

Polymer rheology has a long research tradition and holds an important position in the scientific *** is supposed to be a valuable subject to the vast polymer *** article points out the exciting developments that are transforming our understanding of the world of polymer *** discuss not only the emerging challenges in the area but also how China might wish to seize the moment,pick up the trend and take advantage of the potential economic benefits to the huge petro-chemical industry of China.

关键词： polymer rheology polymer processing elastic yielding nonlinear phenomena shear banding

Micro-computed tomography utility for estimation of intraparenchymal spinal cord cystic lesions in small animals

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Neural Regeneration Research 2021年第11期16卷 2293-2298页

作者： Mahmoud Farrag Dipak D.Pukale Nic D.Leipzig Integrated Bioscience Program The University of AkronAkronOHUSA Department of Chemical Biomolecularand Corrosion EngineeringThe University of AkronAkronOHUSA Department of Chemical Biomolecularand Corrosion EngineeringIntegrated Bioscience ProgramThe University of AkronAkronOHUSA

Precise assessment of spinal cord cystic lesions is crucial to formulate effective therapeutic strategies,yet histological assessment of the lesion remains the primary method despite numerous studies showing inconsistent results regarding estimation of lesion size via *** the other hand,despite numerous advances in micro-computed tomography(micro-CT)imaging and analysis that have allowed precise measurements of lesion size,there is not enough published data on its application to estimate intraspinal lesion size in laboratory animal *** work attempts to show that micro-CT can be valuable for spinal cord injury research by demonstrating accurate estimation of syrinx size and compares between micro-CT and traditional histological *** used a post-traumatic syringomyelia rat model to compare micro-CT analysis to conventional histological *** study showed that micro-CT can detect lesions within the spinal cord very similar to ***,micro-CT appears to provide more accurate estimates of the lesions with more measures(e.g.,surface area),can detect compounds within the cord,and can be done with the tissue of interest(spinal cord)*** summary,the experimental work presented here provides one of the first investigations of the use of micro-CT for estimating the size of intraparenchymal cysts and detecting materials within the spinal *** animal procedures were approved by the University of akron Institutional Animal Care and Use Committee(IACUC)(protocol#LRE 16-05-09 approved on May 14,2016).

关键词： cyst size histology intraparenchymal cysts lesion size estimate micro-CT post-traumatic syringomyelia spinal cord imaging spinal cord injury spinal cystic lesion syrinx

CHEMICALLY DEPOSITED SILVER FILM USED AS A SERS-ACTIVE OVER-COATING LAYER FOR POLYMER FILM

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Chinese Journal of Polymer Science 2001年第3期19卷 265-268页

作者： Stephen Z.D. Cheng Department of Polymer Science The University of Akron Akron OH 44325 USA

When colloidal silver particles were chemically deposited onto polymer film as an over-coating layer, surface-enhanced Raman scattering (SERS) spectra could be collected for the surface analysis. SERS measurements of ... 详细信息

关键词： surface enhanced Raman scattering chemically deposited silver polymer film

A review of Pt-based electrocatalysts for oxygen reduction reaction

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Frontiers in Energy 2017年第3期11卷 268-285页

作者： Changlin ZHANG Xiaochen SHEN Yanbo PAN Zhenmeng PENG Department of Chemical and Biomolecular Engineering University of Akron Akron OH 44325 USA

Development of active and durable electro- catalyst for oxygen reduction reaction （ORR） remains one challenge for the polymer electrolyte membrane fuel cell （PEMFC） technology. Pt-based nanomaterials show the greatest promise as electrocatalyst for this reaction among all current catalytic structures. This review focuses on Pt- based ORR catalyst material development and covers the past achievements, current research status and perspectives in this research field. In particular, several important categories of Pt-based catalytic structures and the research advances are summarized. Key factors affecting the catalyst activity and durability are discussed. An outlook of future research direction of ORR catalyst research is provided.

关键词： oxygen reduction reaction (ORR) electrocatalysis platinum catalyst activity durability

Mechanochemistry of cyclobutanes

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Science China Chemistry 2024年第12期67卷 3915-3924页

作者： Roberto Obregon Junpeng Wang School of Polymer Science and Polymer Engineering University of AkronAkronOH 44325USA

The field of polymer mechanochemistry has been revolutionized by implementing force-responsive functional groups—*** rational design of mechanophores enables the controlled use of force to achieve constructive molecular reactivity and material *** a variety of mechanophores have been developed,this Mini Review focuses on cyclobutane,which has brought valuable insights into molecular reactivity and dynamics as well as innovations in *** discuss its reactivity and mechanism,dynamics and stereoselectivity,as well as impacts on material properties.

关键词： mechanochemistry mechanophore cyclobutane

Corrosion Behavior and Hardness of Al-M (M:Mo,Si,Ti,Cr) Alloys

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Acta Metallurgica Sinica(English Letters) 2017年第4期30卷 333-341页

作者： J.Esquivel R.K.Gupta Department of Chemical and Biomolecular Engineering The University of Akron Akron OH 44325-3906 USA

The corrosion behavior of Al-5 at.% Cr, A1-5 at.% Si, Al-5 at.% Mo and Al-5 at.% Ti produced via casting and Al-5 at.% Cr produced by high-energy ball milling and subsequent consolidation by cold pressing was studied using potentiodynamic polarization and surface analysis following constant immersion tests. Alloys were characterized using a scanning electron microscope coupled with the energy-dispersive X-ray spectroscopy and X-ray diffraction analysis. Hardness, a representative of the strength, was also measured. The alloys produced by casting contained coarse intermetallics and therefore exhibited poor corrosion resistance. Al-5 at.% Cr alloy produced by high-energy ball milling exhibited a significantly improved corrosion resistance and hardness, which was attributed to the grain refinement to nanoscale and extended solid solubility of Cr in AL The study indicated that the high-energy ball milling was capable of producing Al alloys with improved corrosion behavior and hardness.

关键词： Corrosion Mechanical alloying Casting Aluminum alloys

Smartphone microendoscopy for high resolution fluorescence imaging

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Journal of Innovative Optical Health Sciences 2016年第5期9卷 114-120页

作者： Xiangqian Hong Vivek K.Nagarajan Dale H.Mugler Bing Yu Department of Biomedical Engineering The University of akron akron Ohio 44325USA

High resolution optical endoscopes are increasingly used in diagnosis of various medical condi-tions of internal organs,such as the cervix and gastrointestinal(GI)tracts,but they are too expensive for use in resource poor *** the other hand,smartphones with high resolution cameras and Internet access have become more affordable,enabling them to difuse into most rural areas and developing countries in the past *** this paper,we describe a smartphone microendoscope that can take fuorescence images with a spatial resolution of 3.1 *** collected from ex vivo,in vnitro and in vivo samples using the device are also *** compact and cost-effective smart phone microendosoope may be envisaged as a powerful tool for detecting pre cancerous lesions of internal organs in low and middle income countries(LMICs).

关键词： Endoscopy imaging systems fluorescence fiber optics

Irregular-Mode Cracking in Fe-3 wt pct Si Alloy

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Journal of Materials Science & Technology 2005年第3期21卷 338-342页

作者： Y.Qiao Department of Civil Engineering, University of akron, akron, OH 44325-3905, USA Department of Civil Engineering University of Akron Akron OH 44325-3905 United States

Due to the non-uniform nature of crack advance, when a cleavage front encounters a high-angle grain boundary, instead of simultaneous break-through along the whole boundary, the front transmission mode can be irregular, which results in a higher fracture resistance and a tortuous percolation behavior. In this paper, this phenomenon is studied quantitatively through the analysis on the work of separation and the change in strain energy for an Fe-3 wt pct Si alloy. The influences of the crystallographic misorientations, the break-through mode, the cleavage front profile, and the grain boundary properties are discussed in detail.

关键词： Fracture toughness Transgranular Iron-silicon alloy Irregular mode