Article
Chemistry, Physical
Pei Bai, Mingchao Ma, Li Sui, Yunlong Guo
Summary: This study demonstrates significant changes in stiffness and the ratio between elastic and viscous responses in thin PDMS films under nanoconfinement, with an enhanced elastic modulus and increased viscous response observed. The results contribute to a better understanding of the nanoconfinement effect on viscoelastic properties of soft matter.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2021)
Article
Chemistry, Multidisciplinary
Maria F. Pantano, Christos Pavlou, Maria Giovanna Pastore Carbone, Costas Galiotis, Nicola M. Pugno, Giorgio Speranza
Summary: In this study, ultrathin PMMA films were evaluated for their mechanical behavior using a homemade nanomechanical device, showing a surprisingly high strain at failure and development of crazes during tensile loading, but without premature fracture. This work may pave the way for the development of glassy thermoplastic films with high ductility at ambient temperatures.
Article
Polymer Science
Lili Zhang, Norman A. Fleck
Summary: Molecular dynamics simulations are used to study the thickness dependence of uniaxial and equi-biaxial tensile responses of ultrathin PMMA films, revealing that tensile failure strain decreases with decreasing film thickness, temperature, and molecular weight, while side-branching plays a secondary role.
Article
Chemistry, Multidisciplinary
Yiwei Qiang, Sumukh S. Pande, Daeyeon Lee, Kevin T. Turner
Summary: Polymer-nanoparticle composite films with high loadings of nanoparticles have various applications. The confinement of polymers due to the high-volume fraction and small size of the nanoparticles can significantly change the properties of polymers. By tuning the extent of confinement and using nanoparticles of different sizes, the fracture toughness of the composite films can be enhanced. Low molecular weight polymers can greatly increase the toughness of nanoparticle packings, while high molecular weight polymers are more effective in toughening large nanoparticle packings.
Article
Polymer Science
Fengliang Wang, Zhenwei Jiang, Xuanyu Lin, Cuiyun Zhang, Keiji Tanaka, Biao Zuo, Wei Zhang, Xinping Wang
Summary: The study found that as the thickness of thin polystyrene films decreased, the entanglement molecular weight increased and the interchain entanglement density decreased, resulting in a decrease in the characteristic time of the wetting ridge at the surface.
Article
Polymer Science
Masayuki Saito, Norifumi L. L. Yamada, Kohzo Ito, Hideaki Yokoyama
Summary: Understanding the mechanical properties and swelling behaviors of ultrathin polymer films is crucial in the field of nanoscience and nanotechnology. This study investigates the mechanical properties and swelling behaviors of ultrathin chemically cross-linked polybutadiene films. It was found that reducing the film thickness increased the Young's modulus and resulted in an unusual stress-relaxation behavior. Moreover, the in-plane swelling of films floating on water was significantly suppressed due to the effects of interface-induced orientations and trapped chain segments acting as pseudo-cross-linking points.
Article
Chemistry, Physical
Claudia Ferreiro-Cordova, Giuseppe Foffi, Olivier Pitois, Chiara Guidolin, Maxime Schneider, Anniina Salonen
Summary: The elastic properties of a soft matter material can be greatly affected by the presence of solid inclusions. This is due to the interactions between the gel backbone and the inclusions, leading to non-trivial changes in the elastic properties. Experimental studies on emulsions confirm the trends observed in simulations.
Article
Biochemistry & Molecular Biology
Gianfranco Cordella, Antonio Tripodo, Francesco Puosi, Dario Pisignano, Dino Leporini
Summary: This paper examines the nanoscale surface instability of ultrathin molecular films deposited on a substrate under uniaxial compression using molecular dynamics simulations. The study reveals the development of one-dimensional wrinkling structures and the scaling relationship between wavelength and film length. It is found that small compressions can be well described, while large compressions lead to increased wrinkling amplitudes with nearly constant cross sections, offering a novel interpretation of instability. These findings may be crucial for designing effective wrinkling and buckling patterns in flexible platforms for electronics and photonics.
INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES
(2021)
Article
Chemistry, Physical
Courtney M. Olson, Aaron M. Massari
Summary: FTIR and 2D-IR spectroscopies were used to study PDMS cross-linked elastomer films, showing that spectral line shapes were greatly influenced by heterogeneity, with only slight differences between heterogeneous and homogeneous dynamics even with significant macroscopic changes in different systems.
JOURNAL OF CHEMICAL PHYSICS
(2021)
Article
Multidisciplinary Sciences
Luke A. Galuska, Eric S. Muckley, Zhiqiang Cao, Dakota F. Ehlenberg, Zhiyuan Qian, Song Zhang, Simon Rondeau-Gagne, Minh D. Phan, John F. Ankner, Ilia N. Ivanov, Xiaodan Gu
Summary: Research shows that obtaining the intrinsic mechanical properties of sub-100nm thin films is challenging, especially in the field of soft organic electronics. Experiments demonstrate subtle yet significant effects of water on the mechanical properties of hydrophobic films.
NATURE COMMUNICATIONS
(2021)
Article
Multidisciplinary Sciences
Jason S. Silver, K. Arda Gunay, Alicia A. Cutler, Thomas O. Vogler, Tobin E. Brown, Bradley T. Pawlikowski, Olivia J. Bednarski, Kendra L. Bannister, Cameron J. Rogowski, Austin G. Mckay, Frank W. DelRio, Bradley B. Olwin, Kristi S. Anseth
Summary: Elevated muscle stiffness enhances migration and proliferation of MuSCs by localizing YAP and TAZ to the nucleus. Ablating YAP and TAZ induces MuSC quiescence after injury and prevents myofiber hypertrophy.
Review
Polymer Science
Bolin Li, Shuqing Zhang, John S. Andre, Zhan Chen
Summary: This review systematically examines the effects of free surface, buried interface, and geometrical confinement on the relaxation behavior of polymer thin films using poly(methyl methacrylate) (PMMA) and polystyrene (PS) as examples. The study also discusses the universal effects of hard and soft confinements and adsorbed nanolayers near a substrate on the glass transition temperature (T-g) of these films. The systematic knowledge presented in the review will aid in the future design of polymer thin films with desired properties for a variety of applications.
PROGRESS IN POLYMER SCIENCE
(2021)
Review
Multidisciplinary Sciences
Elena Missale, Marco Frasconi, Maria F. Pantano
Summary: Ultrathin polymeric films have gained significant attention for their functional applications in coatings, separation membranes, and sensors. Understanding their mechanical properties is crucial for developing robust devices with advanced performances. In this review, we highlight the recent advances in ultrathin organic membranes, focusing on the relationship between structure and mechanical properties. We discuss the preparation methods, investigation techniques, and models for understanding the mechanical response, followed by a discussion on designing mechanically robust organic membranes.
Article
Chemistry, Physical
Yuhan Xiao, Pei Bai, Zhengyang Zhang, Yunlong Guo
Summary: This study investigates the nonlinear viscoelastic-viscoplastic properties of thin polymer films, particularly thin polystyrene (PS) films, under nanoconfinement. The results show that with decreasing film thickness, the viscosity and yield stress increase exponentially and linearly, respectively. The observed rubbery stiffening phenomenon in thin PS films may be attributed to induced molecular orientation by plastic deformation.
JOURNAL OF CHEMICAL PHYSICS
(2023)
Article
Mechanics
Guoxiong Chen, Ru An, Jianfei Xu, Shihua Fu
Summary: In this study, a model was developed to predict tension stiffening in FRP RC beams with different reinforcement ratios. By introducing a correction factor, the model successfully corrected the results of finite element analysis and matched the experimental results. Uneven distributions in the strain of FRP bars were also observed in the study.
COMPOSITE STRUCTURES
(2022)
Article
Medicine, Research & Experimental
Sixue Cheng, Paroma Chakravarty, Karthik Nagapudi, Gregory B. McKenna
Summary: In this study, the isothermal crystallization of compound GDC-0276 was investigated using differential scanning calorimetry and rheometric measurements. Rheological measurements showed better sensitivity in detecting nucleation and onset of crystallization compared to DSC. The temperature-dependent viscosity of GDC-0276 was used to modify the JMA model and construct the TTT diagram for the material, providing insights into crystallization kinetics.
MOLECULAR PHARMACEUTICS
(2021)
Correction
Medicine, Research & Experimental
Sixue Cheng, Paroma Chakravarty, Karthik Nagapudi, Gregory B. McKenna
MOLECULAR PHARMACEUTICS
(2021)
Article
Chemistry, Physical
Satish Chandra Hari Mangalara, Shreejaya Paudel, Gregory B. McKenna
Summary: Mechanical spectral hole burning (MSHB) has been used to investigate the nonlinear dynamics in polymers, providing insights into dynamic heterogeneity and molecular level heterogeneity. Results from studying polycarbonate using MSHB show differences in hole characteristics compared to poly(methyl methacrylate), supporting the hypothesis that hole burning in amorphous polymers is related to the strength of beta-transition.
JOURNAL OF CHEMICAL PHYSICS
(2021)
Article
Chemistry, Physical
Qi Li, Xiaoguang Peng, Dongjie Chen, Gregory B. McKenna
Summary: The study investigates the dynamics of a series of soft colloids with varying corona moduli, showing specific behaviors in concentration dependence. The use of a hard-soft mapping framework and extended theoretical models helps explain the properties and dynamics of soft colloids.
JOURNAL OF COLLOID AND INTERFACE SCIENCE
(2022)
Article
Polymer Science
Dejie Kong, Sourya Banik, Michael J. San Francisco, Megan Lee, Rae M. Robertson Anderson, Charles M. Schroeder, Gregory B. McKenna
Summary: Bulk rheology measurements on concentrated monodisperse ring-linear DNA mixtures are reported for the first time. The behavior of these mixtures is compared with that of pure linear DNA, highlighting the dominant role of linear chains in the dynamics and entanglement scaling of the blends.
Article
Mechanics
Satish Chandra Hari Mangalara, Gregory B. McKenna
Summary: Characterizing the nonlinear behavior of viscoelastic materials is important for understanding their properties. LAOS tests and various analysis methods can provide insights into the nonlinear response of materials. By studying the LAOS experiments of PMMA, we uncover its nonlinear characteristics and observe differences in the behavior of its elastic and viscous components.
MECHANICS OF TIME-DEPENDENT MATERIALS
(2023)
Article
Polymer Science
Kristof Molnar, Hojin Kim, Dongjie Chen, Carin A. Helfer, Gabor Kaszas, Gregory B. McKenna, Julia A. Kornfield, Chunhua Yuan, Judit E. Puskas
Summary: The effect of reaction conditions on the structure of poly(3,6-dioxa-1,8-octanedithiol) (polyDODT) made by Reversible Radical Recombination Polymerization (R3P) was investigated. It was found that high purity cyclic polyDODT had lower viscosity and more compact structure compared to linear samples. However, unusual behavior was observed at higher molecular weights. Further experimentation is needed to elucidate the reasons for these findings.
Article
Engineering, Chemical
Shuang Jin, Gregory B. McKenna
Summary: Cangialosi et al.'s data challenges the general view of smooth dynamics of glass structure recovery, as observed by Kovacs. The reported irregular responses and two mechanism recovery at temperatures below Tg have sparked controversy. This study suggests that poor temperature control in a vacuum oven could explain the anomalous results, and reproduces the experimental results through simulation.
POLYMER ENGINEERING AND SCIENCE
(2022)
Article
Engineering, Chemical
Dejie Kong, Yan Meng, Gregory B. McKenna
Summary: While much is known about the chemistry of amber, there lacks quantitative estimates of molecular weight and amount of cross-linking. This study investigates the network structure of ancient ambers through measurements of rubbery modulus and provides semi-quantitative insights using rubber elasticity theory. The research offers mechanical evidence of chemically cross-linked structures in multiple types of ambers, with molecular weight between cross-links ranging from 1800 to 3000 g/mol and an estimated number of monomers between cross-link junctions between 6 and 10.
POLYMER ENGINEERING AND SCIENCE
(2022)
Review
Engineering, Chemical
Gregory B. McKenna, Dongjie Chen, Satish Chandra Hari Mangalara, Dejie Kong, Sourya Banik
Summary: The present article outlines three subjects in the field of polymer and soft matter physics. The first subject focuses on the concept of an ideal glass transition and presents research on ultra-stable glass. The second subject explores the relationship between polymer nonlinear viscoelasticity and dynamic heterogeneity. The last subject addresses the rheology of circular macromolecules, discussing both historical perspective and recent research findings.
POLYMER ENGINEERING AND SCIENCE
(2022)
Editorial Material
Engineering, Chemical
Shuang Jin, Gregory B. McKenna
Summary: This article responds to the comment made by Cangialosi, Alegria, and Colmenero on our experimental data and provides additional analysis that suggests a smooth structural recovery behavior of glassy materials within a certain range. It also points out the potential temperature control errors in isothermal aging procedures using a vacuum oven.
POLYMER ENGINEERING AND SCIENCE
(2022)
Article
Chemistry, Applied
Yung P. Koh, Zachary T. Fondren, Aric A. Denton, Sindee L. Simon, Gregory B. McKenna
Summary: This study investigates the glass transition and crystallization behaviors of HNAB over a wide range of cooling rates. It quantifies the influence of thermal amorphization on the properties of HNAB and compares the behavior of HNAB prepared by different cooling methods. The study also reports the non-isothermal crystallization response as a function of cooling rate. Furthermore, it compares the thermal stability and decomposition energy of amorphous HNAB with the crystalline counterpart.
PROPELLANTS EXPLOSIVES PYROTECHNICS
(2022)
Article
Polymer Science
Dongjie Chen, Kristof Molnar, Hojin Kim, Carin A. Helfer, Gabor Kaszas, Judit E. Puskas, Julia A. Kornfield, Gregory B. McKenna
Summary: The linear viscoelastic properties of poly(3,6-dioxa-1,8-octanedithiol) (polyDODT) in both melt and solution states were studied. The samples in solution can be used to validate the sample purity.
Article
Polymer Science
Kristof Molnar, Aswathy Sasidharan Pillai, Dongjie Chen, Gabor Kaszas, Gregory B. McKenna, Julia A. Kornfield, Judit E. Puskas
Summary: In this paper, the synthesis and analysis of cyclic polydisulfides, their redox depolymerization, and their interaction with carbon black were reported. Cyclic poly(3,6-dioxa-1,8-octanedithiol)s (pDODT) were synthesized using Reversible Radical Recombination Polymerization (R3P) with varying peroxide concentrations. The molecular weights of pDODTs increased exponentially with increasing peroxide concentrations. NMR analysis confirmed the presence of cyclic structures in pDODTs made with >10 wt % H2O2 and Mn <100,000 g/mol. Dithiothreitol reduced the polymers to monomers and oligomers, and carbon black showed chemical interaction with the polymers. Further analysis of these elastomers is underway.
EUROPEAN POLYMER JOURNAL
(2023)
Article
Materials Science, Ceramics
Dejie Kong, Yan Meng, Gregory B. McKenna
Summary: Here we report the dynamic properties of a 50-million-year-old Fushun amber, which had a fictive temperature Tf approximately 193 K below its glass transition temperature Tg in the thermally rejuvenated state. The density of this ultra-stable amber was 14% higher than the post-rejuvenation value. The relaxation times in the deep glassy state were found to be extremely long, covering thousands of yotta seconds, challenging current theories on glasses and the glass transition.
JOURNAL OF NON-CRYSTALLINE SOLIDS
(2023)
