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Dhar D, McKenas CG, Huang CW, Atkin JM, Dempsey JL, Lockett MR. Quantitative Effects of Disorder on Chemically Modified Amorphous Carbon Electrodes. ACS APPLIED ENERGY MATERIALS 2020; 3:8038-8047. [PMID: 32968715 PMCID: PMC7505236 DOI: 10.1021/acsaem.0c01434] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Real materials are disordered. This disorder influences the properties of these materials and the chemical processes that occur at their interfaces. Gaining a molecular-level understanding of the underlying physical manifestations caused by disordered materials is crucial to unraveling and ultimately controlling the efficiency and performance of these materials in a range of energy-related devices. This understanding necessitates measurement techniques through which disorder can be detected, quantified, and monitored. However, such quantitative measurements are notoriously difficult, as effects often average out in ensemble measurements. In this work, we describe how a combination of electrochemical and spatially resolved surface spectroscopy measurements illuminate a molecular-level picture of disorder in materials. Using amorphous carbon as an intrinsically disordered material, we covalently attached a monolayer of ferrocene. Interfacial electron transfer across the amorphous carbon-ferrocene interface is highly sensitive to disruptions of order. By systematically varying linker properties and surface loadings, the influence of lateral interactions between nonuniformly distributed ferrocene headgroups on ensemble electrochemical measurements is demonstrated. Electrochemical and imaging data collectively indicate that conformational flexibility of the ferrocene moieties provides a mechanism to elude repulsive and unbalanced lateral interactions, while rigid linkages provide direct information about the underlying disorder of the material. This study is the first of its kind to quantify and visualize molecular disorder and heterogeneity with an experimental model accessed through ensemble measurements.
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Affiliation(s)
- Debanjan Dhar
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-3290, United States
| | - Catherine G McKenas
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-3290, United States
| | - Chiung-Wei Huang
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-3290, United States
| | - Joanna M Atkin
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-3290, United States
| | - Jillian L Dempsey
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-3290, United States
| | - Matthew R Lockett
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-3290, United States
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52
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Sun S, Liu C, Rodriguez Melendez D, Yang T, Cremer PS. Immobilization of Phosphatidylinositides Revealed by Bilayer Leaflet Decoupling. J Am Chem Soc 2020; 142:13003-13010. [DOI: 10.1021/jacs.0c03800] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Affiliation(s)
- Simou Sun
- Department of Chemistry, Penn State University, University Park, Pennsylvania 16802, United States
| | - Chang Liu
- Department of Chemistry, Penn State University, University Park, Pennsylvania 16802, United States
| | - Danixa Rodriguez Melendez
- Department of Chemistry, University of Puerto Rico at Cayey, Cayey, Puerto Rico 00737, United States
| | - Tinglu Yang
- Department of Chemistry, Penn State University, University Park, Pennsylvania 16802, United States
| | - Paul S. Cremer
- Department of Chemistry, Penn State University, University Park, Pennsylvania 16802, United States
- Department of Biochemistry and Molecular Biology, Penn State University, University Park, Pennsylvania 16802, United States
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53
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Moon H, Han S, Scott SL. Tuning molecular adsorption in SBA-15-type periodic mesoporous organosilicas by systematic variation of their surface polarity. Chem Sci 2020; 11:3702-3712. [PMID: 33209241 PMCID: PMC7643544 DOI: 10.1039/d0sc00168f] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2020] [Accepted: 03/09/2020] [Indexed: 11/21/2022] Open
Abstract
Surface polarity plays a key role in controlling molecular adsorption at solid-liquid interfaces, with major implications for reactions and separations. In this study, the chemical composition of periodic mesoporous organosilicas (PMOs) was varied by co-condensing Si(OEt)4 with organodisilanes, to create a homologous series of materials with similar surface areas, pore volumes, and hydroxyl contents. Their relative surface polarities, obtained by measuring the fluorescence of a solvatochromic dye, cover a wide range. In this series of PMO materials, EPR spectra of tethered nitroxide radicals show monotonically decreasing mobility as larger fractions of the radicals interact strongly with increasingly non-polar surfaces. The surface properties of the materials also correlate with their affinities for organic molecules dissolved in various solvents. The most polar PMO has negligible affinity for phenol, p-cresol, or furfural when these molecules are dissolved in water. However, stronger solute-surface interactions and favor adsorption as the surface polarity decreases. The trend is reversed for furfural in benzene, where weaker solvent-surface interactions result in higher adsorption on polar surfaces. In DMSO, furfural adsorption is suppressed due to the similar strengths of solute-surface and solvent-surface interactions. Thus, the polarity of the surface relative to the solvent is critical for molecular adsorption. These findings show how adsorption/desorption can be precisely and systematically tuned by appropriate choice of both solvent and surface, and contribute to a predictive strategy for the design of catalytic and separations processes.
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Affiliation(s)
- Hyunjin Moon
- Department of Chemical Engineering , University of California , Santa Barbara , California 93106-5080 , USA . ;
| | - Songi Han
- Department of Chemical Engineering , University of California , Santa Barbara , California 93106-5080 , USA . ;
- Department of Chemistry & Biochemistry , University of California , Santa Barbara , California 93106-9510 , USA
| | - Susannah L Scott
- Department of Chemical Engineering , University of California , Santa Barbara , California 93106-5080 , USA . ;
- Department of Chemistry & Biochemistry , University of California , Santa Barbara , California 93106-9510 , USA
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54
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55
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Monroe J, Barry M, DeStefano A, Aydogan Gokturk P, Jiao S, Robinson-Brown D, Webber T, Crumlin EJ, Han S, Shell MS. Water Structure and Properties at Hydrophilic and Hydrophobic Surfaces. Annu Rev Chem Biomol Eng 2020; 11:523-557. [PMID: 32169001 DOI: 10.1146/annurev-chembioeng-120919-114657] [Citation(s) in RCA: 46] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The properties of water on both molecular and macroscopic surfaces critically influence a wide range of physical behaviors, with applications spanning from membrane science to catalysis to protein engineering. Yet, our current understanding of water interfacing molecular and material surfaces is incomplete, in part because measurement of water structure and molecular-scale properties challenges even the most advanced experimental characterization techniques and computational approaches. This review highlights progress in the ongoing development of tools working to answer fundamental questions on the principles that govern the interactions between water and surfaces. One outstanding and critical question is what universal molecular signatures capture the hydrophobicity of different surfaces in an operationally meaningful way, since traditional macroscopic hydrophobicity measures like contact angles fail to capture even basic properties of molecular or extended surfaces with any heterogeneity at the nanometer length scale. Resolving this grand challenge will require close interactions between state-of-the-art experiments, simulations, and theory, spanning research groups and using agreed-upon model systems, to synthesize an integrated knowledge of solvation water structure, dynamics, and thermodynamics.
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Affiliation(s)
- Jacob Monroe
- Department of Chemical Engineering, University of California, Santa Barbara, California 93106, USA;
| | - Mikayla Barry
- Department of Materials, University of California, Santa Barbara, California 93106, USA
| | - Audra DeStefano
- Department of Chemical Engineering, University of California, Santa Barbara, California 93106, USA;
| | - Pinar Aydogan Gokturk
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Sally Jiao
- Department of Chemical Engineering, University of California, Santa Barbara, California 93106, USA;
| | - Dennis Robinson-Brown
- Department of Chemical Engineering, University of California, Santa Barbara, California 93106, USA;
| | - Thomas Webber
- Department of Chemical Engineering, University of California, Santa Barbara, California 93106, USA;
| | - Ethan J Crumlin
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.,Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Songi Han
- Department of Chemical Engineering, University of California, Santa Barbara, California 93106, USA; .,Department of Chemistry and Biochemistry, University of California, Santa Barbara, California 93106, USA
| | - M Scott Shell
- Department of Chemical Engineering, University of California, Santa Barbara, California 93106, USA;
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56
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Di Trani N, Pimpinelli A, Grattoni A. Finite-Size Charged Species Diffusion and pH Change in Nanochannels. ACS APPLIED MATERIALS & INTERFACES 2020; 12:12246-12255. [PMID: 32068385 DOI: 10.1021/acsami.9b19182] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
Molecular transport through nanofluidic structures exhibits properties that are unique at the nanoscale. The high surface-to-volume ratio of nanometer-sized confined spaces renders particle interactions with the surface of central importance. The electrical double layer (EDL) at the solid-liquid interface of charged surfaces generates an enrichment of counterions and the exclusion of co-ions that lead to a change in their diffusivity. In addition, the diffusive transport is altered by steric and hydrodynamic interactions between fluid molecules and the boundaries. An extensive body of literature investigates molecular transport at the nanoscale. However, most studies account for ionic species as point charges, severely limiting the applicability of the results to "large" nanofluidic systems. Moreover, and even more importantly, the change of pH in the nanoconfined region inside nanochannels has been completely overlooked. Corroborated by experimental data, here we present an all-encompassing analysis of molecular diffusion from the micro- to the ultra-nanoscale. While accounting for finite-size ions, we compute self-consistently the pH inside the channels. Surprisingly, we found that the concentration of ions H+ can change by more than 2 orders of magnitude compared to the bulk, hugely affecting molecular transport. Further, we found that counterions exhibit both enrichment and exclusion, depending on the size of nanochannels. Achieving a greater understanding of the effective transport properties of fluids at the nanoscale will fill the gap in knowledge that still limits development of innovative systems for medicine and industrial applications alike.
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Affiliation(s)
- Nicola Di Trani
- Department of Nanomedicine, Houston Methodist Research Institute, Houston, Texas 77030, United States
- University of Chinese Academy of Science (UCAS), 19 Yuquan Road, Beijing 100049, Shijingshan, China
| | - Alberto Pimpinelli
- Smalley-Curl Institute and MSNE Department, Rice University, Houston, Texas 77005, United States
| | - Alessandro Grattoni
- Department of Nanomedicine, Houston Methodist Research Institute, Houston, Texas 77030, United States
- Department of Surgery, Houston Methodist Hospital, Houston, Texas 77030, United States
- Department of Radiation Oncology, Houston Methodist Hospital, Houston, Texas 77030, United States
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57
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Mostafavi SH, Mettry M, Gill AD, Easley CJ, Hooley RJ, Bardeen CJ. Heterogeneous kinetics of photoinduced cross-linking of silica nanoparticles with surface-tethered anthracenes. Chem Phys Lett 2020. [DOI: 10.1016/j.cplett.2019.137059] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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58
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Chen M, Zhou H, Zhu R, Lu X, He H. Closest-Packing Water Monolayer Stably Intercalated in Phyllosilicate Minerals under High Pressure. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2020; 36:618-627. [PMID: 31886678 DOI: 10.1021/acs.langmuir.9b03394] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
The directional hydrogen-bond (HB) network and nondirectional van der Waals (vdW) interactions make up the specificity of water. Directional HBs could construct an ice-like monolayer in hydrophobic confinement even in the ambient regime. Here, we report a water monolayer dominated by vdW interactions confined in a phyllosilicate interlayer under high pressure. Surprisingly, it was in a thermodynamically stable state coupled with bulk water at the same pressure (P) and temperature (T), as revealed by the thermodynamic integration approach on the basis of molecular dynamics (MD) simulations. Both classical and ab initio MD simulations showed water O atoms were stably trapped and exhibited an ordered hexagonal closest-packing arrangement, but OH bonds of water reoriented frequently and exhibited a specific two-stage reorientation relaxation. Strikingly, hydration in the interlayer under high pressure had no relevance with surface hydrophilicity rationalized by the HB forming ability, which, however, determines wetting in the ambient regime. Intercalated water molecules were trapped by vdW interactions, which shaped the closest-packing arrangement and made hydration energetically available. The high pressure-volume term largely drives hydration, as it compensates the entropy penalty which is restricted by a relatively lower temperature. This vdW water monolayer should be ubiquitous in the high pressure but low-temperature regime.
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Affiliation(s)
- Meng Chen
- CAS Key Laboratory of Mineralogy and Metallogeny/Guangdong Provincial Key Laboratory of Mineral Physics and Materials, Guangzhou Institute of Geochemistry, Institutions of Earth Science , Chinese Academy of Sciences (CAS) , Guangzhou 510640 , China
| | - Huijun Zhou
- CAS Key Laboratory of Mineralogy and Metallogeny/Guangdong Provincial Key Laboratory of Mineral Physics and Materials, Guangzhou Institute of Geochemistry, Institutions of Earth Science , Chinese Academy of Sciences (CAS) , Guangzhou 510640 , China
- University of Chinese Academy of Sciences , Beijing 100049 , China
| | - Runliang Zhu
- CAS Key Laboratory of Mineralogy and Metallogeny/Guangdong Provincial Key Laboratory of Mineral Physics and Materials, Guangzhou Institute of Geochemistry, Institutions of Earth Science , Chinese Academy of Sciences (CAS) , Guangzhou 510640 , China
| | - Xiancai Lu
- State Key Laboratory for Mineral Deposits Research, School of Earth Sciences and Engineering , Nanjing University , Nanjing 210093 , China
| | - Hongping He
- CAS Key Laboratory of Mineralogy and Metallogeny/Guangdong Provincial Key Laboratory of Mineral Physics and Materials, Guangzhou Institute of Geochemistry, Institutions of Earth Science , Chinese Academy of Sciences (CAS) , Guangzhou 510640 , China
- University of Chinese Academy of Sciences , Beijing 100049 , China
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59
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Choong CE, Wong KT, Jang SB, Nah IW, Choi J, Ibrahim S, Yoon Y, Jang M. Fluoride removal by palm shell waste based powdered activated carbon vs. functionalized carbon with magnesium silicate: Implications for their application in water treatment. CHEMOSPHERE 2020; 239:124765. [PMID: 31520981 DOI: 10.1016/j.chemosphere.2019.124765] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/18/2019] [Revised: 09/03/2019] [Accepted: 09/04/2019] [Indexed: 06/10/2023]
Abstract
In this study, palm shell activated carbon powder (PSAC) and magnesium silicate (MgSiO3) modified PSAC (MPSAC) were thoroughly investigated for fluoride (F-) adsorption. F- adsorption isotherms showed that PSAC and MPSAC over-performed some other reported F- adsorbents with adsorption capacities of 116 mg g-1 and 150 mg g-1, respectively. Interestingly, the MgSiO3 impregnated layer changed the adsorption behavior of F- from monolayer to heterogeneous multilayer based on the Langmuir and Freundlich isotherm models verified by chi-square test (X2). Thermodynamic parameters indicated that the F- adsorption on PSAC and MPSAC was spontaneous and exothermic. PSAC and MPSAC were characterized using FESEM-EDX, XRD, FTIR and XPS to investigate the F- adsorption mechanism. Based on the regeneration tests using NaOH (0.01 M), PSAC exhibited poor regeneration (<20%) while MPSAC had steady adsorption efficiencies (∼70%) even after 5 regeneration cycles. This is due to highly polarized C-F bond was found on PSAC while Mg-F bond was distinguished on MPSAC, evidently denoting that the F- adsorption is mainly resulted from the exchange of hydroxyl (-OH) group. It was concluded that PSAC would be a potential adsorbent for in-situ F- groundwater remediation due to its capability to retain F- without leaching out in a wide range pH. MPSAC would be an alternative adsorbent for ex-situ F- water remediation because it can easily regenerate with NaOH solution. With the excellent F- adsorption properties, both PSAC and MPSAC offer as promising adsorbents for F- remediation in the aqueous phase.
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Affiliation(s)
- Choe Earn Choong
- Department of Environmental Engineering, Kwangwoon University, 20 Kwangwoon-Ro, Nowon-Gu, Seoul, 01897, Republic of Korea
| | - Kien Tiek Wong
- Department of Environmental Engineering, Kwangwoon University, 20 Kwangwoon-Ro, Nowon-Gu, Seoul, 01897, Republic of Korea
| | - Seok Byum Jang
- Department of Environmental Engineering, Kwangwoon University, 20 Kwangwoon-Ro, Nowon-Gu, Seoul, 01897, Republic of Korea
| | - In Wook Nah
- Center for Energy Convergence, Korea Institute of Science and Technology, Hwarangno 14-gil 5, Seongbuk-Gu, Seoul, 02792, Republic of Korea
| | - Jaeyoung Choi
- Green City Technology Institute, Korea Institute of Science and Technology, Hwarangno 14-gil 5, Seongbuk-Gu, Seoul, 02792, Republic of Korea
| | - Shaliza Ibrahim
- Institute of Ocean and Earth Sciences (IOES), University of Malaya, Kuala Lumpur, 50603, Malaysia
| | - Yeomin Yoon
- Department of Civil and Environmental Engineering, University of South Carolina, Columbia, 300 Main Street, SC, 29208, USA
| | - Min Jang
- Department of Environmental Engineering, Kwangwoon University, 20 Kwangwoon-Ro, Nowon-Gu, Seoul, 01897, Republic of Korea.
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60
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Fringes S, Schwemmer C, Rawlings CD, Knoll AW. Deterministic Deposition of Nanoparticles with Sub-10 nm Resolution. NANO LETTERS 2019; 19:8855-8861. [PMID: 31693376 DOI: 10.1021/acs.nanolett.9b03687] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Accurate deposition of nanoparticles at defined positions on a substrate is still a challenging task, because it requires simultaneously stable long-range transport and attraction to the target site and precise short-range orientation and deposition. Here we present a method based on geometry-induced energy landscapes in a nanofluidic slit for particle manipulation: Brownian motors or electro-osmotic flows are used for particle delivery to the target area. At the target site, electrostatic trapping localizes and orients the particles. Finally, reducing the gap distance of the slit leads sequentially to a focusing of the particle position and a jump into adhesive contact by several nanometers. For 60 nm gold spheres, we obtain a placement accuracy of 8 nm. The versatility of the method is demonstrated further by a stacked assembly of nanorods and the directed deposition of InAs nanowires.
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Affiliation(s)
- Stefan Fringes
- IBM Research - Zurich , Säumerstrasse 4 , 8803 Rüschlikon , Switzerland
| | - C Schwemmer
- IBM Research - Zurich , Säumerstrasse 4 , 8803 Rüschlikon , Switzerland
| | - Colin D Rawlings
- IBM Research - Zurich , Säumerstrasse 4 , 8803 Rüschlikon , Switzerland
| | - Armin W Knoll
- IBM Research - Zurich , Säumerstrasse 4 , 8803 Rüschlikon , Switzerland
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61
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Lin W, Klein J. Control of surface forces through hydrated boundary layers. Curr Opin Colloid Interface Sci 2019. [DOI: 10.1016/j.cocis.2019.10.001] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
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62
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Li Y, Cao Y. The molecular mechanisms underlying mussel adhesion. NANOSCALE ADVANCES 2019; 1:4246-4257. [PMID: 36134404 PMCID: PMC9418609 DOI: 10.1039/c9na00582j] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2019] [Accepted: 10/09/2019] [Indexed: 06/12/2023]
Abstract
Marine mussels are able to firmly affix on various wet surfaces by the overproduction of special mussel foot proteins (mfps). Abundant fundamental studies have been conducted to understand the molecular basis of mussel adhesion, where the catecholic amino acid, l-3,4-dihydroxyphenylalanine (DOPA) has been found to play the major role. These studies continue to inspire the engineering of novel adhesives and coatings with improved underwater performances. Despite the fact that the recent advances of adhesives and coatings inspired by mussel adhesive proteins have been intensively reviewed in literature, the fundamental biochemical and biophysical studies on the origin of the strong and versatile wet adhesion have not been fully covered. In this review, we show how the force measurements at the molecular level by surface force apparatus (SFA) and single molecule atomic force microscopy (AFM) can be used to reveal the direct link between DOPA and the wet adhesion strength of mussel proteins. We highlight a few important technical details that are critical to the successful experimental design. We also summarize many new insights going beyond DOPA adhesion, such as the surface environment and protein sequence dependent synergistic and cooperative binding. We also provide a perspective on a few uncharted but outstanding questions for future studies. A comprehensive understanding on mussel adhesion will be beneficial to the design of novel synthetic wet adhesives for various biomedical applications.
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Affiliation(s)
- Yiran Li
- Shenzhen Research Institute of Nanjing University Shenzhen 518057 China
- Department of Physics, Collaborative Innovation Center of Advanced Microstructures, National Laboratory of Soli State Microstructure, Nanjing University Nanjing 210093 China
| | - Yi Cao
- Shenzhen Research Institute of Nanjing University Shenzhen 518057 China
- Department of Physics, Collaborative Innovation Center of Advanced Microstructures, National Laboratory of Soli State Microstructure, Nanjing University Nanjing 210093 China
- Chemistry and Biomedicine Innovation Center, Nanjing University Nanjing 210093 China
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63
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Dallin BC, Van Lehn RC. Spatially Heterogeneous Water Properties at Disordered Surfaces Decrease the Hydrophobicity of Nonpolar Self-Assembled Monolayers. J Phys Chem Lett 2019; 10:3991-3997. [PMID: 31265306 DOI: 10.1021/acs.jpclett.9b01707] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Understanding the relationship between hydrophobicity and the properties of functionalized surfaces is vital to the design of materials that interact in aqueous environments. In this Letter, we use atomistic molecular dynamics simulations to investigate the effects of surface order on the hydrophobicity of self-assembled monolayers (SAMs) containing nonpolar ligands. We find that the interfacial hydrophobicity is highly correlated with SAM order and, strikingly, poorly correlated with the solvent-accessible surface area, which typically has been related to interfacial hydrophobicity. Analysis of spatial variations in both SAM and water properties reveals that the SAM-water interface is pinned near regions of disordered SAM surfaces with increased free volume, decreasing the overall interfacial hydrophobicity. Spatial variations in ligand end group positions at disordered SAM surfaces thus translate to spatial variations in hydrophobicity, yielding heterogeneous surface properties. These findings provide new insights into how surface order can alter the hydrophobicity of chemically uniform surfaces.
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Affiliation(s)
- Bradley C Dallin
- Department of Chemical and Biological Engineering , University of Wisconsin-Madison , 1415 Engineering Drive , Madison , Wisconsin 53706 , United States
| | - Reid C Van Lehn
- Department of Chemical and Biological Engineering , University of Wisconsin-Madison , 1415 Engineering Drive , Madison , Wisconsin 53706 , United States
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64
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Sivashanmugan K, Squire K, Kraai JA, Tan A, Zhao Y, Rorrer GL, Wang AX. Biological Photonic Crystal-Enhanced Plasmonic Mesocapsules: Approaching Single-Molecule Optofluidic-SERS Sensing. ADVANCED OPTICAL MATERIALS 2019; 7:1900415. [PMID: 32775144 PMCID: PMC7410161 DOI: 10.1002/adom.201900415] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/07/2019] [Indexed: 05/05/2023]
Abstract
Surface-enhanced Raman scattering (SERS) sensing in microfluidic devices, namely optofluidic-SERS, suffers an intrinsic trade-off between mass transport and hot spot density, both of which are required for ultra-sensitive detection. To overcome this compromise, photonic crystal-enhanced plasmonic mesocapsules are synthesized, utilizing diatom biosilica decorated with in-situ growth silver nanoparticles (Ag NPs). In our optofluidic-SERS testing, 100× higher enhancement factors and greater than 1,000× better detection limit were achieved compared with traditional colloidal Ag NPs, the improvement of which is attributed to unique properties of the mesocapsules. First, the porous diatom biosilica frustules serve as carrier capsules for high density Ag NPs that form high density plasmonic hot-spots. Second, the submicron-pores embedded in the frustule walls not only create a large surface-to-volume ratio allowing for effective analyte capture, but also enhance the local optical field through the photonic crystal effect. Last, the mesocapsules provide effective mixing with analytes as they are flowing inside the microfluidic channel. The reported mesocapsules achieved single molecule detection of Rhodamine 6G in microfluidic devices and were further utilized to detect 1 nM of benzene and chlorobenzene compounds in tap water with near real-time response, which successfully overcomes the constraint of traditional optofluidic sensing.
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Affiliation(s)
- Kundan Sivashanmugan
- School of Electrical Engineering and Computer Science, Oregon State University, Corvallis, OR 97331, USA
| | - Kenneth Squire
- School of Electrical Engineering and Computer Science, Oregon State University, Corvallis, OR 97331, USA
| | - Joseph A. Kraai
- School of Chemical, Biological, and Ecological Engineering, Oregon State University, Corvallis, OR 97331, USA
| | - Ailing Tan
- School of Electrical Engineering and Computer Science, Oregon State University, Corvallis, OR 97331, USA
- School of Information Science and Engineering, The Key Laboratory for Special Fiber and Fiber Sensor of Hebei Province, Yanshan University, Qinhuangdao 066004, China
| | - Yong Zhao
- School of Electrical Engineering and Computer Science, Oregon State University, Corvallis, OR 97331, USA
- School of Electrical Engineering, The Key Laboratory of Measurement Technology and Instrumentation of Hebei Province, Yanshan University, Qinhuangdao, 066004, China
| | - Gregory L. Rorrer
- School of Chemical, Biological, and Ecological Engineering, Oregon State University, Corvallis, OR 97331, USA
| | - Alan X. Wang
- School of Electrical Engineering and Computer Science, Oregon State University, Corvallis, OR 97331, USA
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65
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Abstract
Interfaces between water and silicates are ubiquitous and relevant for, among others, geochemistry, atmospheric chemistry, and chromatography. The molecular-level details of water organization at silica surfaces are important for a fundamental understanding of this interface. While silica is hydrophilic, weakly hydrogen-bonded OH groups have been identified at the surface of silica, characterized by a high O-H stretch vibrational frequency. Here, through a combination of experimental and theoretical surface-selective vibrational spectroscopy, we demonstrate that these OH groups originate from very weakly hydrogen-bonded water molecules at the nominally hydrophilic silica interface. The properties of these OH groups are very similar to those typically observed at hydrophobic surfaces. Molecular dynamics simulations illustrate that these weakly hydrogen-bonded water OH groups are pointing with their hydrogen atom toward local hydrophobic sites consisting of oxygen bridges of the silica. An increased density of these molecular hydrophobic sites, evident from an increase in weakly hydrogen-bonded water OH groups, correlates with an increased macroscopic contact angle.
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66
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Yabushita M, Grosso-Giordano NA, Fukuoka A, Katz A. Selective Sequestration of Aromatics from Aqueous Mixtures with Sugars by Hydrophobic Molecular Calixarene Cavities Grafted on Silica. ACS APPLIED MATERIALS & INTERFACES 2018; 10:39670-39678. [PMID: 30398841 DOI: 10.1021/acsami.8b13273] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The separation of aromatic contaminants from sugar-aromatic aqueous mixtures is required in second-generation biorefineries because aromatic compounds deactivate (bio)catalysts typically involved in upgrading lignocellulosic biomass to fuels and chemicals. This separation remains challenging, however, because of the degree of molecular recognition needed to sequester dilute aromatic impurities from concentrated sugar streams. Herein, we demonstrate that hydrophobic cavities of p- tert-butylcalix[4]arene macrocycles grafted on amorphous silica (calix/SiO2) perform this separation selectively and efficiently by acting as selective molecular hosts that adsorb aromatic compounds (5-hydroxymethylfurfural, vanillin, and vanillic acid) while excluding monomeric sugar (glucose chosen as a prototypical model) in aqueous mixtures. By comparing calix/SiO2 to a range of organically modified SiO2 surfaces and other porous adsorbents, we demonstrate that the organization of hydrophobic functional groups within discrete nests consisting of calixarene cavities is crucial for facilitating the adsorption of aromatics. Density functional theory calculations of the host-guest complex indicate that adsorption is brought about by weak dispersive (van der Waals) interactions between tert-butyl upper-rim substituents in calixarene hosts and aromatic guests. Calix/SiO2 can be repeatedly reused, demonstrating its viability as an adsorbent within a continuous biorefining process. These calix/SiO2 adsorbents expand the palette of materials available for selective sugar-aromatic separations, which until now have been limited to pyrene-based sites of metal-organic framework NU-1000, and demonstrate that sites consisting of relatively simple hydrophobic tert-butyl substituents organized around a hemispherical molecular cavity provide a sufficient degree of molecular recognition for performing this separation selectively.
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Affiliation(s)
- Mizuho Yabushita
- Department of Chemical and Biomolecular Engineering , University of California, Berkeley , Berkeley , California 94720 , United States
- Institute for Catalysis , Hokkaido University , Sapporo , Hokkaido 001-0021 , Japan
| | - Nicolás A Grosso-Giordano
- Department of Chemical and Biomolecular Engineering , University of California, Berkeley , Berkeley , California 94720 , United States
| | - Atsushi Fukuoka
- Institute for Catalysis , Hokkaido University , Sapporo , Hokkaido 001-0021 , Japan
| | - Alexander Katz
- Department of Chemical and Biomolecular Engineering , University of California, Berkeley , Berkeley , California 94720 , United States
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Cordon MJ, Harris JW, Vega-Vila JC, Bates JS, Kaur S, Gupta M, Witzke ME, Wegener EC, Miller JT, Flaherty DW, Hibbitts DD, Gounder R. Dominant Role of Entropy in Stabilizing Sugar Isomerization Transition States within Hydrophobic Zeolite Pores. J Am Chem Soc 2018; 140:14244-14266. [DOI: 10.1021/jacs.8b08336] [Citation(s) in RCA: 50] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Affiliation(s)
- Michael J. Cordon
- Charles D. Davidson School of Chemical Engineering, Purdue University, 480 Stadium Mall Drive, West Lafayette, Indiana 47907, United States
| | - James W. Harris
- Charles D. Davidson School of Chemical Engineering, Purdue University, 480 Stadium Mall Drive, West Lafayette, Indiana 47907, United States
| | - Juan Carlos Vega-Vila
- Charles D. Davidson School of Chemical Engineering, Purdue University, 480 Stadium Mall Drive, West Lafayette, Indiana 47907, United States
| | - Jason S. Bates
- Charles D. Davidson School of Chemical Engineering, Purdue University, 480 Stadium Mall Drive, West Lafayette, Indiana 47907, United States
| | - Sukhdeep Kaur
- Department of Chemical Engineering, University of Florida, 1030 Center Drive, Gainesville, Florida 32611, United States
| | - Mohit Gupta
- Department of Chemical Engineering, University of Florida, 1030 Center Drive, Gainesville, Florida 32611, United States
| | - Megan E. Witzke
- Department of Chemical and Biomolecular Engineering, University of Illinois Urbana−Champaign, Urbana, Illinois 61801, United States
| | - Evan C. Wegener
- Charles D. Davidson School of Chemical Engineering, Purdue University, 480 Stadium Mall Drive, West Lafayette, Indiana 47907, United States
| | - Jeffrey T. Miller
- Charles D. Davidson School of Chemical Engineering, Purdue University, 480 Stadium Mall Drive, West Lafayette, Indiana 47907, United States
| | - David W. Flaherty
- Department of Chemical and Biomolecular Engineering, University of Illinois Urbana−Champaign, Urbana, Illinois 61801, United States
| | - David D. Hibbitts
- Department of Chemical Engineering, University of Florida, 1030 Center Drive, Gainesville, Florida 32611, United States
| | - Rajamani Gounder
- Charles D. Davidson School of Chemical Engineering, Purdue University, 480 Stadium Mall Drive, West Lafayette, Indiana 47907, United States
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Patterning polarity. Nat Rev Chem 2018. [DOI: 10.1038/s41570-018-0036-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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69
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Computational discovery of chemically patterned surfaces that effect unique hydration water dynamics. Proc Natl Acad Sci U S A 2018; 115:8093-8098. [PMID: 30038028 DOI: 10.1073/pnas.1807208115] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The interactions of water with solid surfaces govern their apparent hydrophobicity/hydrophilicity, influenced at the molecular scale by surface coverage of chemical groups of varied nonpolar/polar character. Recently, it has become clear that the precise patterning of surface groups, and not simply average surface coverage, has a significant impact on the structure and thermodynamics of hydration layer water, and, in turn, on macroscopic interfacial properties. Here we show that patterning also controls the dynamics of hydration water, a behavior frequently thought to be leveraged by biomolecules to influence functional dynamics, but yet to be generalized. To uncover the role of surface heterogeneities, we couple a genetic algorithm to iterative molecular dynamics simulations to design the patterning of surface functional groups, at fixed coverage, to either minimize or maximize proximal water diffusivity. Optimized surface configurations reveal that clustering of hydrophilic groups increases hydration water mobility, while dispersing them decreases it, but only if hydrophilic moieties interact with water through directional, hydrogen-bonding interactions. Remarkably, we find that, across different surfaces, coverages, and patterns, both the chemical potential for inserting a methane-sized hydrophobe near the interface and, in particular, the hydration water orientational entropy serve as strong predictors for hydration water diffusivity, suggesting that these simple thermodynamic quantities encode the way surfaces control water dynamics. These results suggest a deep and intriguing connection between hydration water thermodynamics and dynamics, demonstrating that subnanometer chemical surface patterning is an important design parameter for engineering solid-water interfaces with applications spanning separations to catalysis.
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70
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Biller JR, Barnes R, Han S. Perspective of Overhauser dynamic nuclear polarization for the study of soft materials. Curr Opin Colloid Interface Sci 2018. [DOI: 10.1016/j.cocis.2018.02.007] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
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