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Crystallization of POSS in a PEG-Based Multiblock Polyurethane: Toward A Hybrid Hydrogel

MRS Online Proceedings Library 2021年第1期847卷 59-64页

作者： Jian Wu Qing Ge Kelly A. Burke Patrick T. Mather Chemical Engineering Department and Polymer Program Institute of Materials Science University of Connecticut Storrs USA Department of Macromolecular Science and Engineering Case Western Reserve University Cleveland USA

Building upon earlier success in forming materials with crystalline ordering of POSS via the telechelic architecture with POSS end-capping polyethylene glycols, here we report similar ordering in PEG-POSS thermoplastic polyurethane applicable to a novel hybrid hydrogel. Thus, a unique series of hybrid thermoplastic polyurethanes (TPUs) were synthesized using poly(ethylene glycol) (PEG) as soft segment and incorporating an isobutyl-functionalized POSS diol (TMP POSS diol) in the hard segment. The molecular weight of PEG was systematically varied to include 10, 20, and 35 kDa while the mole ratio of PEG to POSS diol (as chain extender) was chosen as 8:1. The diisocyanate employed for TPU polymerization was 4, 4'-methylenebis(phenyl-isocyanate) (MDI). Wide-angle X-ray diffraction (WAXD) studies revealed that both the hydrophilic soft segments (PEG) and hydrophobic hard segments (POSS) can form crystalline structures driven by micro-phase separation, itself due to thermodynamic incompatibility. Differential scanning calorimetry (DSC) and rheological studies revealed that thermal history is important in controlling the crystallization of a POSS-rich nanophase. Increasing the cooling rate monotonically decreases the crystallinity of POSS-rich phase and results in a decrease in the ultimate dynamic storage modulus following POSS crystallization and an increase of the loss angle for temperatures above Tm of PEG and below Tm of POSS. We conclude that both composition and thermal history are key factors in determing the internal network built by the POSS nanophase, which will have a significant influence on the properties of the resulting hybrid hydrogels now being studied.

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Assessment of Simple Adhesive Substrates for Quantifying Microplastics

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SSRN 2022年

作者： Rieland, Julie M. Hu, Zeyuan Deese, Julian S. Love, Brian J. The University of Michigan United States Department of Materials Science and Engineering Department of Biomedical Engineering Macromolecular Science and Engineering Graduate Program

Microplastics are a growing environmental concern, with a large body of evidence documenting substantial distribution of plastic material in virtually all environmental compartments. Countermeasures that help to bind, aggregate, or coalesce these distributed particles might result in lower human and animal exposures. Pressure sensitive adhesives (PSAs) have been identified as a viable microplastic (MP) capture mechanism with a range of potential use conditions. As with any countermeasure, there is a need to evaluate potential solutions in terms of collection efficiency, cost, ease of installation, etc. Expanding on our previous work, spray-coated PSAs were investigated as submerged surfaces as tools to assess MP binding in aqueous dispersions. Resins containing two differing molecular weights of poly(2-ethylhexyl acrylate) PSA (92k and 950k), and a 50:50 by weight mixture of the two resins were applied as spray-coated substrates to compare the effect of resin composition on MP-adhesive binding. Thin films of PSA (92k 6 ± 1 μm, 950k 4 ± 2 μm, 50:50 BD 6.5 ± 1 μm) were sprayed on borosilicate glass slides using a commercial air brush. Polydisperse nylon-12 particles varying in size from 15-30 µm in diameter were dispersed in deionized water at concentrations between 0.01 and 5 mg mL -1 and agitated under ambient conditions to assess adhesive binding as quantitative comparisons of microparticle capture. Mixed assays were also performed comparing binding of common MP species including polyethylene (50, 200 µm), polystyrene (10 µm), and polyester fibers (1000 µm) to understand how varying composition, size, and form factor affect adsorption. The glass slide method showed increasing linear trends of particle binding with increased adhesive exposure time and MP concentration. The lower molecular weight 92K adhesive had lower viscosity, higher wettability for microplastics but also led to a less stable adhesive film complicating analysis. As a field-deployable scheme for mi

关键词： Aggregates

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Patch-clamp study: Nanoscale hole formation in living cell plasma membrane induced by polymer nanoparticles

Patch-clamp study: Nanoscale hole formation in living cell p...

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235th ACS National Meeting, Spring 2008

作者： Chen, Jiumei Orr, Bradford Hoil, Mark Banaszak Program of Macromolecular Science and Engineering University of Michigan Ann Arbor MI 48109 United States Department of Physics University of Michigan Ann Arbor MI 48109 United States Program of Applied Physics University of Michigan Ann Arbor MI 48109 United States Department of Chemistry University of Michigan Ann Arbor MI 48109 United States

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Graphene-loaded nanofiber-modified electrode: A novel and sensitive electrochemical detection system

Graphene-loaded nanofiber-modified electrode: A novel and se...

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Nanotechnology 2014: Graphene, CNTs, Particles, Films and Composites - 2014 NSTI Nanotechnology Conference and Expo, NSTI-Nanotech 2014

作者： Rodthongkum, Nadnudda Ruecha, Nipapan Promphet, Nadtinan Rangkupan, Rathapol Vachet, Richard W. Chailapakul, Orawon Metallurgy and Materials Science Research Institute Chulalongkorn University Pathumwan Bangkok 10330 Thailand Program in Macromolecular Science Faculty of Science Chulalongkorn University Pathumwan Bangkok 10330 Thailand Petrochemical and Polymer Science Faculty of Science Chulalongkorn University Thailand Department of Chemistry University of Massachusetts Amherst Amherst MA 01002 United States Electrochemistry and Optical Spectroscopy Research Unit Department of Chemistry Chulalongkorn University Pathumwan Bangkok 10330 Thailand

ISBN: (纸本)9781482258264

A novel electrode based on graphene/polyaniline/polystyrene (G/PANI/PS) nanofibers has been prepared via electrospinning for the determination of biomolecule (i.e. dopamine) and heavy metals (i.e. Cd2+ and Pb 2+). The factors affecting the electrochemical sensitivity and morphology of G/PANI/PS nanofibers, such as percentage of G loading (%G), electrospinning time, type of organic solvent and concentration of polymer were investigated and optimized. The obtained nanofibers were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and cyclic voltammetry (CV). The G/PANI/PS nanofiber-modified electrodes were used for selective and sensitive determination of dopamine. A very low limit of detection (LOD: 0.05 nM) and limit of quantification (LOQ: 0.30 nM) were achieved for dopamine. Furthermore, these modified electrodes were successfully applied for sensitive and simultaneous determination of Cd2+ and Pb2+.

关键词： Nanofibers

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A POWERLESS OPTICAL MICROSENSOR FOR MONITORING INTRAOCULAR PRESSURE WITH KERATOPROSTHESES

A POWERLESS OPTICAL MICROSENSOR FOR MONITORING INTRAOCULAR P...

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International Conference on Solid-State Sensors, Actuators and Microsystems

作者： M. Ghannad-Rezaie M. N. Gulari R. de Melo Franco S. I. Mian N. Chronis Department of Biomedical Engineering University of Michigan Macromolecular Science and Engineering Program University of Michigan Department of Ophthalmology and Visual Sciences University of Michigan

ISBN: (纸本)9781467359825

Frequent and accurate measurement of intraocular pressure (IOP) is required in monitoring patients who are at high risk of developing glaucoma. We present a novel electronic-free, wireless, optomechanical implantable IOP microsensor. The microsensor has a total volume of less than 1mm~3 and is integrated into a keratoprosthesis (KPro). We performed ex-vivo experiments by implanting the microsensor/KPro assembly into human eyebank globes for two weeks. Our microsensor had 2 mmHg accuracy and less than 1 mmHg zero-drift.

关键词： Wireless pressure sensor intraocular pressure implantable biocompatible near infrared

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Simulations of layer-by-layer assembly of polyelectrolyte multilayers

Simulations of layer-by-layer assembly of polyelectrolyte mu...

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Society of Plastics Engineers Annual Technical Conference 2005, ANTEC 2005

作者： Patel, Pritesh Jeon, Junhwan Dobrynin, Andrey V. Mather, Patrick T. Dept. Chemical Engineering University of Connecticut Storrs CT 06269 Polymer Program University of Connecticut Storrs CT 06269 Dept. Physics University of Connecticut Storrs CT 06269 Dept. Macromolecular Science and Engineering Case Western Reserve University Cleveland OH 44106

Layer-by-layer processing of polyelectrolyte multilayers is a polymer processing technique that enables molecular-level control over the formation of precision coatings. Despite present widespread use, a fundamental understanding of the process remains elusive prompting us to employ molecular dynamics simulations of the process. Multilayer build-up was achieved through sequential adsorption of charged polymers in a layer-bylayer fashion from dilute solutions, the strong electrostatic attraction between oppositely charged polyelectrolytes driving multilayer growth. We find that a charge reversal after each deposition step is critical for steady multilayer growth and a linear increase in polymer mass adsorbed after several deposition steps. Also, substantial intermixing between chains adsorbed during different deposition steps is observed. These results will be summarized, along with a perspective for the future, in our interactive presentation.

关键词： Multilayers

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Dispersion of cobalt ferrite functionalized graphene nanoplatelets in PLA for EMI shielding applications 36

Dispersion of cobalt ferrite functionalized graphene nanopla...

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36th Technical Conference of the American Society for Composites 2021: Composites Ingenuity Taking on Challenges in Environment-Energy-Economy, ASC 2021

作者： Anurakparadorn, Kanat Taub, Alan Michielssen, Eric Department of Materials Science and Engineering Macromolecular Science and Engineering Program University of Michigan 2300 Hayward St Ann ArborMI48109 United States Department of Mechanical Engineering University of Michigan 2350 Hayward St Ann ArborMI48109 United States Department of Electrical Engineering and Computer Science University of Michigan 1310 Beal Ave Ann ArborMI48109 United States

ISBN: (纸本)9781713837596

The proliferation of wireless technology calls for the development of cost-effective Electromagnetic Interference (EMI) shielding materials that reduce the susceptibility of high-speed electronic circuits to undesired incoming radiation. Ideally, such materials offer protection over wide frequency ranges and are insensitive to the polarization or angle of incidence of the impinging fields. Here, next-generation EMI shielding materials composed of polymer composites with conductive and magnetic fillers are introduced. It is shown that careful control of the concentration and dispersion of the polymers’ conductive and magnetic constituents permits tuning of the composites’ intrinsic electrical and magnetic properties. The resulting EMI shields are lightweight, cheap and offer greater protection than traditional metal gaskets and foams. In this work, cobalt ferrite magnetic nanoparticles (CoFe2O4) decorated on graphene-based material were dispersed in polylactic acid (PLA) matrix for high EM absorption level in X-band (8-12 GHz). The decoration of the magnetic particles was performed on the as-prepared conductive graphene nanoplatelets (GNP) and reduced graphene oxide (rGO). GNP composites exhibited higher DC conductivity, and permittivity than rGO composites. This is attributed to issues associated with the reduction process, including a lack of conductivity due to the insulated oxygen functional groups and the reduction in the lateral size. Compared with rGOs, the lack of out-plane functional groups causes the cobalt ferrite nanoparticles to agglomerate and not cover the entire surface of the GNPs. These morphological differences improve the magnetization and EM absorption of the composite system. The compatibilizer (pyrene-PLA-OH) was added to the composites to enhance dispersion of the GNPs in the polymer matrix which benefits in higher absorption of the shield. The influence of the compatibilizer on parameter, the reflection loss (RL) of the composite were determi

关键词： Cost effectiveness

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Spatiotemporal multi-omics: exploring molecular landscapes in aging and regenerative medicine

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Military Medical Research 2025年第4期12卷 528-566页

作者： Liu-Xi Chu Wen-Jia Wang Xin-Pei Gu Ping Wu Chen Gao Quan Zhang Jia Wu Da-Wei Jiang Jun-Qing Huang Xin-Wang Ying Jia-Men Shen Yi Jiang Li-Hua Luo Jun-Peng Xu Yi-Bo Ying Hao-Man Chen Ao Fang Zun-Yong Feng Shu-Hong An Xiao-Kun Li Zhou-Guang Wang Affiliated Cixi Hospital Wenzhou Medical University Oujiang Laboratory (Zhejiang Lab for Regenerative Medicine Vision and Brain Health)School of Pharmaceutical ScienceWenzhou Medical University National Key Laboratory of Macromolecular Drug Development and Manufacturing School of Pharmaceutical ScienceWenzhou Medical University State Key Laboratory of Bioelectronics School of Biological Science&Medical EngineeringSoutheast University School of Pharmaceutical Sciences Guangdong Provincial Key Laboratory of New Drug ScreeningSouthern Medical University Department of Human Anatomy Shandong First Medical University&Shandong Academy of Medical Sciences Integrative Muscle Biology Laboratory Division of Regenerative and Rehabilitative SciencesUniversity of Tennessee Health Science Center Key Laboratory for Laboratory Medicine Ministry of EducationZhejiang Provincial Key Laboratory of Medical GeneticsSchool of Laboratory Medicine and Life ScienceWenzhou Medical University Key Laborator y of Imaging Diagnosis and Minimally Invasive Intervention Research Institute of Imaging Diagnosis and Minimally Invasive Intervention Researchthe Fifth Affiliated Hospital of Wenzhou Medical UniversityLishui Hospital of Zhejiang University School and Hospital of Stomatology Wenzhou Medical University Departments of Diagnostic Radiology SurgeryChemical and Biomolecular Engineeringand Biomedical EngineeringYong Loo Lin School of Medicine and College of Design and EngineeringNational University of Singapore Clinical Imaging Research Centre Centre for Translational MedicineYong Loo Lin School of MedicineNational University of Singapore Nanomedicine Translational Research Program NUS Center for NanomedicineYong Loo Lin School of MedicineNational University of Singapore Institute of Molecular and Cell Biology Agency for ScienceTechnologyand Research (A*STAR)

Aging and regeneration represent complex biological phenomena that have long captivated the scientific community. To fully comprehend these processes, it is essential to investigate molecular dynamics through a lens that encompasses both spatial and temporal dimensions. Conventional omics methodologies, such as genomics and transcriptomics, have been instrumental in identifying critical molecular facets of aging and regeneration. However, these methods are somewhat limited, constrained by their spatial resolution and their lack of capacity to dynamically represent tissue alterations. The advent of emerging spatiotemporal multi-omics approaches, encompassing transcriptomics, proteomics, metabolomics, and epigenomics, furnishes comprehensive insights into these intricate molecular dynamics. These sophisticated techniques facilitate accurate delineation of molecular patterns across an array of cells, tissues, and organs, thereby offering an in-depth understanding of the fundamental mechanisms at play. This review meticulously examines the significance of spatiotemporal multi-omics in the realms of aging and regeneration research. It underscores how these methodologies augment our comprehension of molecular dynamics, cellular interactions, and signaling pathways. Initially, the review delineates the foundational principles underpinning these methods, followed by an evaluation of their recent applications within the field. The review ultimately concludes by addressing the prevailing challenges and projecting future advancements in the field. Indubitably, spatiotemporal multi-omics are instrumental in deciphering the complexities inherent in aging and regeneration, thus charting a course toward potential therapeutic innovations.

关键词： Spatiotemporal multi-omics Aging and regeneration Cellular interactions Innovative therapeutic strategies

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Structural Relaxations of Thin Polymer Films

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Physical Review Letters 2012年第26期108卷 268304-268304页

作者： Bradley Frieberg Emmanouil Glynos Peter F. Green Macromolecular Science and Engineering Program University of Michigan Ann Arbor Michigan 48109 USA Departments of Material Science and Engineering University of Michigan Ann Arbor Michigan 48109 USA Chemical Engineering University of Michigan Ann Arbor Michigan 48109 USA

Time-dependent changes of thermodynamic properties due to structural relaxations and physical aging occur in all glasses. We show that the physical aging of thin supported films of star-shaped macromolecules, with f arms of length Narm, exhibits average aging dynamics that are sensitive to f and Narm. Regions of the films in proximity to interfaces age at substantially different rates than the interior of the film; this is also true of linear chain systems. This behavior may be reconciled in terms of a universal picture that accounts only for changes in the local Tg of the films.

关键词： POLYMERS THIN films RELAXATION phenomena THERMODYNAMICS LINEAR systems STRUCTURAL dynamics

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A powerless optical microsensor for monitoring intraocular pressure with keratoprostheses

A powerless optical microsensor for monitoring intraocular p...

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2013 17th International Conference on Solid-State Sensors, Actuators and Microsystems, TRANSDUCERS and EUROSENSORS 2013

作者： Ghannad-Rezaie, M. Gulari, M.N. De Melo Franco, R. Mian, S.I. Chronis, N. Department of Biomedical Engineering University of Michigan Ann Arbor United States Macromolecular Science and Engineering Program University of Michigan Ann Arbor United States Department of Ophthalmology and Visual Sciences University of Michigan Ann Arbor United States Department of Mechanical Engineering University of Michigan Ann Arbor United States

ISBN: (纸本)9781467359818

Frequent and accurate measurement of intraocular pressure (IOP) is required in monitoring patients who are at high risk of developing glaucoma. We present a novel electronic-free, wireless, optomechanical implantable IOP microsensor. The microsensor has a total volume of less than 1mm3 and is integrated into a keratoprosthesis (KPro). We performed ex-vivo experiments by implanting the microsensor/KPro assembly into human eyebank globes for two weeks. Our microsensor had 2 mmHg accuracy and less than 1 mmHg zero-drift. © 2013 IEEE.

关键词： Risk assessment

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