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Peng J, Cheng Y, Tomsia AP, Jiang L, Cheng Q. Thermochromic Artificial Nacre Based on Montmorillonite. ACS APPLIED MATERIALS & INTERFACES 2017; 9:24993-24998. [PMID: 28685566 DOI: 10.1021/acsami.7b07953] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Nacre-inspired nanocomposites have attracted a great deal of attention in recent years because of their special mechanical properties and universality of the underlying principles of materials engineering. The ability to respond to external stimuli will augment the high toughness and high strength of artificial nacre-like composites and open new technological horizons for these materials. Herein, we fabricated robust artificial nacre based on montmorillonite (MMT) that combines robustness with reversible thermochromism. Our artificial nacre shows great potential in various fields such as aerospace and sensors and opens an avenue to fabricate artificial nacre responsive to other external stimuli in the future.
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Affiliation(s)
- Jingsong Peng
- Key Laboratory of Bio-inspired Smart Interfacial Science and Technology of Ministry of Education, School of Chemistry, Beijing Advanced Innovation Center for Biomedical Engineering, Beihang University , Beijing 100191, P. R. China
| | - Yiren Cheng
- Key Laboratory of Bio-inspired Smart Interfacial Science and Technology of Ministry of Education, School of Chemistry, Beijing Advanced Innovation Center for Biomedical Engineering, Beihang University , Beijing 100191, P. R. China
| | - Antoni P Tomsia
- Key Laboratory of Bio-inspired Smart Interfacial Science and Technology of Ministry of Education, School of Chemistry, Beijing Advanced Innovation Center for Biomedical Engineering, Beihang University , Beijing 100191, P. R. China
- Lawrence Berkeley National Laboratory , Berkeley, California 94720, United States
| | - Lei Jiang
- Key Laboratory of Bio-inspired Smart Interfacial Science and Technology of Ministry of Education, School of Chemistry, Beijing Advanced Innovation Center for Biomedical Engineering, Beihang University , Beijing 100191, P. R. China
| | - Qunfeng Cheng
- Key Laboratory of Bio-inspired Smart Interfacial Science and Technology of Ministry of Education, School of Chemistry, Beijing Advanced Innovation Center for Biomedical Engineering, Beihang University , Beijing 100191, P. R. China
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2
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Zhang B, Tao H, Niu X, Li S, Chen HQ. Lysozyme distribution, structural identification, and in vitro release of starch-based microgel-lysozyme complexes. Food Chem 2017; 227:137-141. [DOI: 10.1016/j.foodchem.2017.01.073] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2016] [Revised: 12/16/2016] [Accepted: 01/15/2017] [Indexed: 02/04/2023]
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Baumler SM, Reidy TM, Blanchard GJ. Diffusional motion as a gauge of fluidity and interfacial adhesion. Supported alkylphosphonate monolayers. J Colloid Interface Sci 2016; 468:145-155. [PMID: 26835584 DOI: 10.1016/j.jcis.2016.01.034] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2015] [Revised: 01/15/2016] [Accepted: 01/16/2016] [Indexed: 11/30/2022]
Abstract
We report on the use of diffusion measurements to gauge the fluidity and surface binding properties of a molecular monolayer. The monolayer film consists of octadecyl-1-phosphonic acid (ODPA) and controlled amounts of a lyso-phosphatidic acid tagged with the fluorescent probe BODIPY (BLPA). The monolayer films were formed using a Langmuir-Blodgett (LB) trough and deposited onto a glass slide. Monolayer morphology was characterized during film formation using Brewster angle microscopy (BAM). Fluorescence Recovery After Photobleaching (FRAP) microscopy was used to measure translational diffusion of BLPA and Fluorescence Anisotropy Decay Imaging (FADI) was used to measure rotational diffusion of the BLPA chromophore. These results provide information on the motional freedom of the probe and, importantly, on the strength of interaction between the probe and the support. Compositional variations in the monolayer give rise to changes in constituent dynamics that reflect intermolecular interactions.
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Affiliation(s)
- S M Baumler
- Michigan State University, Department of Chemistry, 578 S. Shaw Lane, East Lansing, MI 48824, USA.
| | - Thomas M Reidy
- Michigan State University, Department of Chemistry, 578 S. Shaw Lane, East Lansing, MI 48824, USA.
| | - G J Blanchard
- Michigan State University, Department of Chemistry, 578 S. Shaw Lane, East Lansing, MI 48824, USA.
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Thome I, Bauer S, Vater S, Zargiel K, Finlay JA, Arpa-Sancet MP, Alles M, Callow JA, Callow ME, Swain GW, Grunze M, Rosenhahn A. Conditioning of self-assembled monolayers at two static immersion test sites along the east coast of Florida and its effect on early fouling development. BIOFOULING 2014; 30:1011-1021. [PMID: 25303331 DOI: 10.1080/08927014.2014.957195] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Among the first events after immersion of surfaces in the ocean is surface 'conditioning'. Here, the accumulation and composition of the conditioning films formed after immersion in the ocean are analyzed. In order to account for different surface chemistries, five self-assembled monolayers that differ in resistance to microfouling and wettability were used. Water samples from two static immersion test sites along the east coast of Florida were collected at two different times of the year and used for experiments. Spectral ellipsometry revealed that conditioning films were formed within the first 24 h and contact angle goniometry showed that these films changed the wettability and rendered hydrophobic surfaces more hydrophilic and vice versa. Infrared reflection adsorption spectroscopy showed that the composition of the conditioning film depended on both the wettability and immersion site. Laboratory and field assays showed that the presence of a conditioning film did not markedly influence settlement of microorganisms.
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Affiliation(s)
- I Thome
- a Institute of Functional Interfaces (IFG) , Karlsruhe Institute of Technology (KIT) , Eggenstein-Leopoldshafen , Germany
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Weber J, Beier A, Hasselbrink E, Balgar T. Thermally induced conformational changes of Ca-arachidate Langmuir-Blodgett Films at different compression. J Chem Phys 2014; 141:044912. [DOI: 10.1063/1.4891243] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Affiliation(s)
- Jan Weber
- Fakultät für Chemie and Center for Nanointegration (CENIDE), Universität Duisburg-Essen, D-45117 Essen, Germany
| | - Andre Beier
- Fakultät für Chemie and Center for Nanointegration (CENIDE), Universität Duisburg-Essen, D-45117 Essen, Germany
| | - Eckart Hasselbrink
- Fakultät für Chemie and Center for Nanointegration (CENIDE), Universität Duisburg-Essen, D-45117 Essen, Germany
| | - Thorsten Balgar
- Fakultät für Chemie and Center for Nanointegration (CENIDE), Universität Duisburg-Essen, D-45117 Essen, Germany
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Karageorgiev P, Petrov JG, Motschmann H, Moehwald H. Why fluorination of the polar heads reverses the positive sign of the dipole potential of Langmuir monolayers: a vibrational sum frequency spectroscopic study. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2013; 29:4726-4736. [PMID: 23496772 DOI: 10.1021/la304439t] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Natural nonionic amphiphiles forming monolayers, bilayers, micelles, or biomembranes create a positive dipole potential at the boundary with water. In a series of papers we have reported on Langmuir monolayers with CF3 terminals of the polar heads, which show a negative surface dipole potential ΔV (Petrov , J. G.; Andreeva, T. D.; Kurt, D. K.; Möhwald, H. J. Phys. Chem. B 2005, 109, 14102). Here we use vibrational sum frequency spectroscopy (SF) to study the origin of the opposite ΔV signs of Langmuir films of CH3(CH2)20COCH2CH3 (ethyl ether, EE) and CH3(CH2)20COCH2CF3 (fluorinated ethyl ether, FEE). The vibrational sum frequency spectra are recorded at the same film density of the S-phase of the EE and FEE monolayers and analyzed in the spectral regions of OH, COC, CH3, and CF3 stretching vibrations because these functional groups could be responsible for the different dipole potentials. We compare the rearrangement of the pure water surface by EE and FEE monolayers and the conformations of EE and FEE polar heads. The analysis is performed according to the three-capacitor model of the dipole potential of Langmuir monolayers (Demchak, R. T.; Fort, T., Jr. J. Colloid Interface Sci. 1974, 46, 191). The results show that reversal of the ΔV sign caused by fluorination of the polar heads originates from the upward-oriented CF3 terminals of the FEE heads, whose negative normal dipole moment component determines the negative dipole potential of the FEE monolayer.
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Affiliation(s)
- Peter Karageorgiev
- Institute of Physical and Theoretical Chemistry, University of Regensburg, Regensburg, Germany
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Soleimani M, Khani A, Dalali N, Behbehani GR. Improvement in the Cleaning Performance Towards Protein Soils in Laundry Detergents by Protease Immobilization on the Silica Nanoparticles. J SURFACTANTS DETERG 2012. [DOI: 10.1007/s11743-012-1397-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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8
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Pensa E, Vericat C, Grumelli D, Salvarezza RC, Park SH, Longo GS, Szleifer I, Méndez De Leo LP. New insight into the electrochemical desorption of alkanethiol SAMs on gold. Phys Chem Chem Phys 2012; 14:12355-67. [PMID: 22870508 PMCID: PMC3472450 DOI: 10.1039/c2cp41291h] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A combination of Polarization Modulation Infrared Reflection Absorption Spectroscopy (PMIRRAS) under electrochemical control, Electrochemical Scanning Tunneling Microscopy (ECSTM) and Molecular Dynamics (MD) simulations has been used to shed light on the reductive desorption process of dodecanethiol (C12) and octadecanethiol (C18) SAMs on gold in aqueous electrolytes. Experimental PMIRRAS, ECSTM and MD simulations data for C12 desorption are consistent with formation of randomly distributed micellar aggregates stabilized by Na(+) ions, coexisting with a lying-down phase of molecules. The analysis of pit and Au island coverage before and after desorption is consistent with the thiolate-Au adatoms models. On the other hand, PMIRRAS and MD data for C18 indicate that the desorbed alkanethiolates adopt a Na(+) ion-stabilized bilayer of interdigitated alkanethiolates, with no evidence of lying down molecules. MD simulations also show that both the degree of order and tilt angle of the desorbed alkanethiolates change with the surface charge on the metal, going from bilayers to micelles. These results demonstrate the complexity of the alkanethiol desorption in the presence of water and the fact that chain length and counterions play a key role in a complex structure.
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Affiliation(s)
- Evangelina Pensa
- Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas (INIFTA- CONICET- CCT La Plata), 1900 La Plata, Buenos Aires, Argentina
| | - Carolina Vericat
- Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas (INIFTA- CONICET- CCT La Plata), 1900 La Plata, Buenos Aires, Argentina
| | - Doris Grumelli
- Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas (INIFTA- CONICET- CCT La Plata), 1900 La Plata, Buenos Aires, Argentina
| | - Roberto C. Salvarezza
- Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas (INIFTA- CONICET- CCT La Plata), 1900 La Plata, Buenos Aires, Argentina
| | - Sung Hyun Park
- Department of Biomedical Engineering, Northwestern University, Evanston, Illinois 60208, U.S.A
- Chemistry of Life Processes Institute, Northwestern University, Evanston, Illinois 60208, U.S.A
| | - Gabriel S. Longo
- Chemistry of Life Processes Institute, Northwestern University, Evanston, Illinois 60208, U.S.A
- Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, U.S.A
| | - Igal Szleifer
- Department of Biomedical Engineering, Northwestern University, Evanston, Illinois 60208, U.S.A
- Chemistry of Life Processes Institute, Northwestern University, Evanston, Illinois 60208, U.S.A
| | - Lucila P. Méndez De Leo
- INQUIMAE, CONICET, DQIAQF, FCEN, UBA, Ciudad Universitaria, Pabellón II. Buenos Aires, Argentina
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Casher DL, Kobr L, Michl J. Average orientation of a molecular rotor embedded in a Langmuir-Blodgett monolayer. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2012; 28:1625-1637. [PMID: 22133069 DOI: 10.1021/la2037789] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
A molecular rotor in which a naphthalene rotator is attached through a silicon atom to three fatty acid chains has been synthesized, and Langmuir-Blodgett techniques were used to deposit on silica surfaces monolayers of its calcium salt, both neat and diluted with stearic acid salts. The monolayer films have been characterized by ellipsometry and Fourier transform infrared (FT-IR) grazing-incidence attenuated total internal reflection (GATR) spectroscopy on Si-SiO(2) and by UV-vis absorption spectroscopy on SiO(2). The measurements were combined with calculations of the electronic (INDO/S) and vibrational (DFT) transition moment directions to deduce the average orientation of the rotor molecules, including the naphthalene ring, relative to the surface. In both neat and mixed films, the naphthalene ring is found to preferentially tilt toward the surface, enough that its rotation is most likely hindered. A comparable picture was obtained from molecular mechanics calculations on a mixed film of the naphthalene rotor and stearic acid.
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Affiliation(s)
- Deborah L Casher
- Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309-0215, USA
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Soleimani M, Khani A, Najafzadeh K. α-Amylase immobilization on the silica nanoparticles for cleaning performance towards starch soils in laundry detergents. ACTA ACUST UNITED AC 2012. [DOI: 10.1016/j.molcatb.2011.07.011] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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11
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Miljković M, Bird B, Diem M. Line shape distortion effects in infrared spectroscopy. Analyst 2012; 137:3954-64. [DOI: 10.1039/c2an35582e] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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12
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Ramin MA, Le Bourdon G, Daugey N, Bennetau B, Vellutini L, Buffeteau T. PM-IRRAS investigation of self-assembled monolayers grafted onto SiO2/Au substrates. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2011; 27:6076-6084. [PMID: 21486004 DOI: 10.1021/la2006293] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Polarization modulation infrared reflection absorption spectroscopy (PM-IRRAS) was used to characterize self-assembled monolayers (SAMs). Novel ester-terminated organosilicon coupling agents possessing a trialkoxysilyl headgroup and a urea group in the linear alkyl chains (4) were synthesized and grafted onto SiO(2)/Au substrates (SiO(2) film of 200 Å thickness deposited on gold mirror). This composite substrate allowed the anchoring of SAMs and preserved the high reflectivity for infrared radiation. PM-IRRAS spectra with very high signal-to-noise ratios have been obtained in the mid-infrared spectral range allowing monitoring of the grafted SAMs. Quantitative analysis of the measured signal is described to compare PM-IRRAS and conventional IRRAS spectra. This quantitative analysis has been validated since the band intensities in the corrected PM-IRRAS and conventional IRRAS spectra are identical. Orientation information on the different functional groups has been obtained comparing the corrected PM-IRRAS spectrum with the one calculated using isotropic optical constants of ester-terminated organosilicon coupling agents 4. The carbonyls of the urea groups are preferentially parallel to the substrate surface favoring intermolecular hydrogen bonding and consequently a close packing of the molecules attached to the surface. By contrast, the alkyl chains present gauche defects and are poorly oriented.
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Affiliation(s)
- Michaël A Ramin
- Institut des Sciences Moléculaires (UMR 5255-CNRS), Université Bordeaux 1, 351 Cours de la Libération, 33405 Talence, France
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Ohtake T, Ogawa K. Structure Change of Chemically Adsorbed Monolayer Having Many Kinds of Alkyl Chain Lengths. J DISPER SCI TECHNOL 2011. [DOI: 10.1080/01932691003662423] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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14
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Jenneskens LW, Verhey HJ, van Ramesdonk HJ, Verhoeven JW, van Malssen KF, Schenk H. Intramolecular charge-transfer fluorescence of 1-phenyl-4-[(4-cyano-1-naphthyl)methylene]piperidine (fluoroprobe) as a sensor for phase transitions in the solid state. ACTA ACUST UNITED AC 2010. [DOI: 10.1002/recl.19921111202] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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15
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Lee SH, Chae B, Kim HC, Kim SB, Jung YM, Lee SW. Photoreaction and molecular reorientation studies of ultra-violet light irradiated azobenzene containing polymer films using two-dimensional correlation infrared spectroscopy. J Mol Struct 2010. [DOI: 10.1016/j.molstruc.2009.10.008] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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16
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Naik S, Gupta A. Effects of substrate on the melting behavior of Cd arachidate Langmuir–Blodgett films. Colloids Surf B Biointerfaces 2010; 77:150-4. [DOI: 10.1016/j.colsurfb.2010.01.016] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2009] [Revised: 01/12/2010] [Accepted: 01/22/2010] [Indexed: 11/30/2022]
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17
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Grumelli D, Méndez De Leo LP, Bonazzola C, Zamlynny V, Calvo EJ, Salvarezza RC. Methylene blue incorporation into alkanethiol SAMs on Au(111): effect of hydrocarbon chain ordering. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2010; 26:8226-8232. [PMID: 20356031 DOI: 10.1021/la904594p] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
A detailed polarization modulation infrared reflection absorption spectroscopy, scanning tunneling microscopy, and electrochemical study on methylene blue (MB) incorporation into alkanethiolate self-assembled monolayers (SAMs) on Au(111) is reported. Results show that the amount of MB incorporated in the SAMs reaches a maximum for intermediate hydrocarbon chain lengths (C10-C12). Well-ordered SAMs of long alkanethiols (C > C12) hinder the incorporation of the MB molecules into the SAM. On the other hand, less ordered SAMs of short alkanethiols (C < or = C6) are not efficient to retain the MB incorporated through the defects. For C12 the amount of incorporated MB increases as the SAM disorder is increased. This information is essential to the design of efficient thiol-based Au vectors for transport and delivery of molecules as well as thiol-based Au devices for molecular sensing.
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Affiliation(s)
- Doris Grumelli
- Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas, 1900 La Plata, Buenos Aires, Argentina.
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Sun X, Chen T, Huang S, Cai F, Chen X, Yang Z, Li L, Cao H, Lu Y, Peng H. UV-Induced Chromatism of Polydiacetylenic Assemblies. J Phys Chem B 2010; 114:2379-82. [DOI: 10.1021/jp910592y] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Xuemei Sun
- Key Laboratory of Molecular Engineering of Polymers of Ministry of Education, Department of Macromolecular Science, and Laboratory of Advanced Materials, Fudan University, Shanghai 200438, China, and Department of Chemical and Biomolecular Engineering, University of California, Los Angeles, California 90095
| | - Tao Chen
- Key Laboratory of Molecular Engineering of Polymers of Ministry of Education, Department of Macromolecular Science, and Laboratory of Advanced Materials, Fudan University, Shanghai 200438, China, and Department of Chemical and Biomolecular Engineering, University of California, Los Angeles, California 90095
| | - Sanqing Huang
- Key Laboratory of Molecular Engineering of Polymers of Ministry of Education, Department of Macromolecular Science, and Laboratory of Advanced Materials, Fudan University, Shanghai 200438, China, and Department of Chemical and Biomolecular Engineering, University of California, Los Angeles, California 90095
| | - Fangjing Cai
- Key Laboratory of Molecular Engineering of Polymers of Ministry of Education, Department of Macromolecular Science, and Laboratory of Advanced Materials, Fudan University, Shanghai 200438, China, and Department of Chemical and Biomolecular Engineering, University of California, Los Angeles, California 90095
| | - Xuli Chen
- Key Laboratory of Molecular Engineering of Polymers of Ministry of Education, Department of Macromolecular Science, and Laboratory of Advanced Materials, Fudan University, Shanghai 200438, China, and Department of Chemical and Biomolecular Engineering, University of California, Los Angeles, California 90095
| | - Zhibin Yang
- Key Laboratory of Molecular Engineering of Polymers of Ministry of Education, Department of Macromolecular Science, and Laboratory of Advanced Materials, Fudan University, Shanghai 200438, China, and Department of Chemical and Biomolecular Engineering, University of California, Los Angeles, California 90095
| | - Li Li
- Key Laboratory of Molecular Engineering of Polymers of Ministry of Education, Department of Macromolecular Science, and Laboratory of Advanced Materials, Fudan University, Shanghai 200438, China, and Department of Chemical and Biomolecular Engineering, University of California, Los Angeles, California 90095
| | - Hui Cao
- Key Laboratory of Molecular Engineering of Polymers of Ministry of Education, Department of Macromolecular Science, and Laboratory of Advanced Materials, Fudan University, Shanghai 200438, China, and Department of Chemical and Biomolecular Engineering, University of California, Los Angeles, California 90095
| | - Yunfeng Lu
- Key Laboratory of Molecular Engineering of Polymers of Ministry of Education, Department of Macromolecular Science, and Laboratory of Advanced Materials, Fudan University, Shanghai 200438, China, and Department of Chemical and Biomolecular Engineering, University of California, Los Angeles, California 90095
| | - Huisheng Peng
- Key Laboratory of Molecular Engineering of Polymers of Ministry of Education, Department of Macromolecular Science, and Laboratory of Advanced Materials, Fudan University, Shanghai 200438, China, and Department of Chemical and Biomolecular Engineering, University of California, Los Angeles, California 90095
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Tan MC, Ying JY, Chow GM. Interfacial properties and in vitro cytotoxic effects of surface-modified near infrared absorbing Au-Au(2)S nanoparticles. JOURNAL OF MATERIALS SCIENCE. MATERIALS IN MEDICINE 2009; 20:2091-2103. [PMID: 19468832 DOI: 10.1007/s10856-009-3779-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2009] [Accepted: 05/05/2009] [Indexed: 05/27/2023]
Abstract
Near infrared (NIR) absorbing Au-Au(2)S nanoparticles were modified with surfactants of different hydrocarbon chain lengths to allow loading of anticancer drug, cisplatin. The interfacial interactions and surfactant chain length effects on drug loading, optical properties and cytotoxicity were discussed in this work. Short-chain surfactants were oriented closer to the surface normal and were adsorbed at higher densities. Surface modification also changed the optical properties of the particles. Notably, particles modified with short-chain surfactants exhibited a red shift, whereas particles modified with long-chain surfactants showed a blue shift. The in vitro cytotoxicity of drug-loaded surface-modified particles was dependent on the surfactants' chain length. Significant cytotoxicity was observed for 1 mg/ml of drug-loaded particles using surfactants with the shortest chain length. After NIR triggered drug release, the released Pt compounds were observed to be cytotoxic, while remaining nanoparticles did not exhibit any cytotoxicity. Also, the released Pt compounds upon NIR irradiation of drug-loaded particles were observed to be more toxic and had a different molecular structure from cisplatin.
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Affiliation(s)
- Mei Chee Tan
- Molecular Engineering of Biological and Chemical Systems, Singapore-MIT Alliance, Singapore 117576, Singapore.
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Mukherjee S, Datta A, Giglia A, Mahne N, Nannarone S. Chemistry at air/water interface versus reaction in a flask: tuning molecular conformation in thin films. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2009; 25:3519-3528. [PMID: 19708145 DOI: 10.1021/la8023502] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Atomic force microscopy and X-ray reflectivity studies of cobalt stearate Langmuir-Blodgett (LB) films (CoStp) deposited from a preformed bulk sample on quartz substrates showed formation of a Volmer-Weber type monolayer but no multilayers as compared to the excellent multilayers of cobalt stearate films (CoStn) deposited at the air/water interface by the usual LB technique, in spite of both showing bidentate bridging type coordination of cobalt ions with the carboxylate group. The difference is attributed to existence of different headgroup conformers, observed from Fourier transform infrared (FTIR) studies. The CoStp films had a higher energy 'boat' conformation with linear O-Co-O linkage, whereas CoStn formed a low energy conformer with a bent O-Co-O configuration (bond angle of 105 degrees). Present results support the necessity of bidentate bridging coordination in multilayer deposition, but rejects its sufficiency by bringing out the crucial role played by air/water interface. Differences in surface pressure-molecular area isotherms and hydrocarbon tail-tail interactions (evident from FTIR spectra) of the films support the above statement. Methyl-methyl interactions observed in CoStn samples suggest hierarchy of supramolecular chemistry at the air/water interface in tuning the C-O-Co bond angle essential to satisfy the wetting condition with the substrate and subsequently form LB multilayers.
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Affiliation(s)
- Smita Mukherjee
- Surface Physics Division, Saha Institute of Nuclear Physics, 1/AF Bidhannagar, Kolkata 700 064, India
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Imamura K, Shimomura M, Nagai S, Akamatsu M, Nakanishi K. Adsorption characteristics of various proteins to a titanium surface. J Biosci Bioeng 2009; 106:273-8. [PMID: 18930005 DOI: 10.1263/jbb.106.273] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2008] [Accepted: 06/17/2008] [Indexed: 11/17/2022]
Abstract
Adsorption characteristics of 18 proteins, with different sizes and isoelectric points, to a titanium oxide surface were studied. The adsorption isotherms were categorized based on protein type and pH: type 1, irreversible adsorption; type 2, Langmuir-type reversible adsorption; and type 3, reversible and irreversible adsorption. Most of the proteins tested were irreversibly adsorbed in the pH range of 3-8, whereas most adsorbed reversibly at pH 8.5-9.4. Protamine, with a pI value of 12, adsorbed reversibly in the pH range of 3-9. pH values that gave maximal sums of irreversibly and reversibly adsorbed proteins were in the pH range of 3-8 and tended to increase slightly with the pI value of the corresponding protein. pH values that gave maximal quantities of irreversibly adsorbed protein ranged between 4-6 and were nearly independent of pI.
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Affiliation(s)
- Koreyoshi Imamura
- Department of Bioscience and Biotechnology, Faculty of Engineering, Okayama University, Tsushima-Naka, Okayama 700-8530, Japan
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Mandal P, Talwar SS, Major SS, Srinivasa RS. Orange-red luminescence from Cu doped CdS nanophosphor prepared using mixed Langmuir–Blodgett multilayers. J Chem Phys 2008; 128:114703. [DOI: 10.1063/1.2888930] [Citation(s) in RCA: 81] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Mukherjee S, Datta A, Giglia A, Mahne N, Nannarone S. Relating structure with morphology: A comparative study of perfect Langmuir–Blodgett multilayers. Chem Phys Lett 2008. [DOI: 10.1016/j.cplett.2007.11.069] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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24
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Orientation of the alkyl side chains and glucopyranose rings in Langmuir–Blodgett films of a regioselectively substituted cellulose ether. Colloid Polym Sci 2007. [DOI: 10.1007/s00396-007-1822-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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25
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Haro M, Cea P, Gascón I, Royo FM, López MC. Mixed Langmuir and Langmuir−Blodgett Films of a Proton Sponge and a Fatty Acid: Influence of the Subphase Nature on the Interactions between the Two Components. J Phys Chem B 2007; 111:2845-55. [PMID: 17319711 DOI: 10.1021/jp065954b] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The H+ acceptor activity of a proton sponge, namely, diphenyl bis(octadecylamino)phosphonium bromide, has been studied at the air-liquid interface using several subphases. Mixed Langmuir and Langmuir-Blodgett (LB) films containing the proton sponge and a fatty acid (behenic acid) in the whole composition range have been prepared. Surface pressure versus area per molecule isotherms were recorded and excess Gibbs energies of mixing calculated. The existence of strong interactions between the proton sponge and the fatty acid is observed when the subphase is either pure water or a NaOH aqueous solution. A stoichiometric 1:1 reaction between both molecules takes place at the air-water interface. This reaction has an efficiency close to 100% at high surface pressures, provided the majority anion present in the subphase is OH-. However, when the majority anion is another one, this complex is hardly formed. From the experimental results, we conclude that the acid-base reaction is highly dependent on the protonation state of the proton sponge at the air-liquid interface that is a function of the present counterion in the subphase. The floating films were also transferred onto solid substrates and characterized by means of IR spectroscopy, atomic force microscopy (AFM), and X-ray diffraction to investigate in more detail the complex formation. The interactions between the complex (when formed) and the excess component have been studied in terms of the subphase nature. It was found that the complex is immiscible with the proton sponge, yielding films made of different domains. Nevertheless, the complex is miscible with the fatty acid when the subphase used is an alkaline solution, presumably due to electrostatic interactions between the carboxylate group of the acid and the complex.
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Affiliation(s)
- Marta Haro
- Departamento de Química OrgAnica-Química Física, Facultad de Ciencias, Plaza de San Francisco, Ciudad Universitaria, 50009 Zaragoza, Spain
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Xiao QG, Tao X, Chen JF. Silica Nanotubes Based on Needle-like Calcium Carbonate: Fabrication and Immobilization for Glucose Oxidase. Ind Eng Chem Res 2007. [DOI: 10.1021/ie060935+] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Parra V, Del Caño T, Rodríguez-Méndez ML, De Saja JA, Bouvet M, Shirota Y. Electroactivity of a starburst hole-transport material in Langmuir–Blodgett films. Solid state effects and intervalence charge transfer. Phys Chem Chem Phys 2007; 9:2266-73. [PMID: 17487324 DOI: 10.1039/b618509f] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Here we report on the electroactivity properties of Langmuir-Blodgett (LB) films of the hole-transport molecule 4,4',4''-tris[3-methylphenyl(phenyl)amino] triphenylamine (m-MTDATA). Fairly stable Langmuir films at the air-water interface are accomplished, despite the non-amphiphilic character of the molecule. The reflection-absorption infrared spectroscopy (RAIRS) and Fourier transform infrared (FT-IR) analysis revealed that the molecules arrange with no neat preferential orientation, in agreement with the amorphous glassy nature of this starburst molecule. However, there is a tendency of the molecules to organize in a more planar conformation due to the intermolecular stacking induced by the LB technique. On the other hand, the fundamental electrochemistry (by cyclic voltammetry, CV) of the films is also analyzed. The CV studies of both solution and films reveal that both the solid state and the electrolyte's anions clearly affect the m-MTDATA's electroactivity, exhibiting a unique and broad redox process instead of the two reversible oxidations observed in solution. The oxidization mechanism is discussed. Finally, the spectroelectrochemistry studies evidence that the oxidization of the films leads to new absorption bands, among which the emerging bands in the NIR region ascribed to intervalence charge transfer (IVCT) between the generated aminyl radical cations should be pointed out.
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Affiliation(s)
- Vicente Parra
- Dpto. de Química Física y Química Inorgánica, E.T.S. Ingenieros Industriales, University of Valladolid, Po del Cauce s/n, 47011 Valladolid, Spain.
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Fryer JR, McConnell CM, Hann RA, Eyres BL, Gupta SK. The structure of some Langmuir-Blodgett films. Part I. Substituted phthalocyanines. ACTA ACUST UNITED AC 2006. [DOI: 10.1080/13642819008207565] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Affiliation(s)
- J. R. Fryer
- a Chemistry Department , University of Glasgow , Glasgow , G12 8QQ , Scotland
| | - C. M. McConnell
- a Chemistry Department , University of Glasgow , Glasgow , G12 8QQ , Scotland
| | - R. A. Hann
- b Imperial Chemical Industries p.l.c., Electronics Group , Runcorn , Cheshire , WA7 4QE , England
- c ICI Imagedata , Brantham Manningtree, Essex CO11 1NL
| | - B. L. Eyres
- b Imperial Chemical Industries p.l.c., Electronics Group , Runcorn , Cheshire , WA7 4QE , England
| | - S. K. Gupta
- b Imperial Chemical Industries p.l.c., Electronics Group , Runcorn , Cheshire , WA7 4QE , England
- d Sri Guru Ram Rai College , Dehra Dun , India
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Nayak P, Singh S, Talwar S, Srinivasa R, Major S. Dependence of the structure of zinc arachidate LB multilayers on subphase zinc ion concentration and pH. Colloids Surf A Physicochem Eng Asp 2006. [DOI: 10.1016/j.colsurfa.2005.10.074] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Imamura K, Watanabe I, Sakiyama T, Nakanishi K. Effects of the supporting electrolyte on the kinetics of the removal of proteins adsorbed on a stainless steel surface by H2O2-electrolysis. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2006; 22:7035-40. [PMID: 16863257 DOI: 10.1021/la053494s] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
The effects of different types of supporting electrolytes on the removal of beta-lactoglobulin (beta-Lg) after being adsorbed to a stainless steel surface by a H2O2-electrolysis treatment was investigated. In this process, hydroxyl radicals (*OH), generated by the electrolysis of hydrogen peroxide, decompose the substances adhering to the surface. The removal of the adsorbed protein from the stainless steel surface during the treatment was monitored in situ by ellipsometry. The apparent first-order removal rate constants, k(cl), for 17 types of supporting electrolytes were determined, as well as the current corresponding to the rate of generation of *OH. The k(cl) and generated current values for LiCl, NaCl, KCl, KNO(3), K(2)SO(4), CH(3)COOK, and K(2)CO(3) were all similar. Ca(2+) and Mg(2+) strongly suppressed the removal of the adsorbed protein. The presence of ammonium compounds led to an increase in k(cl) and current values. In H2O2-electrolysis in the presence of potassium phosphate, the removal was extremely rapid, and an apparent increase in the thickness of the adsorbed layer was observed. The mechanisms responsible for the peculiar effects of calcium, magnesium, phosphate, and ammonium compounds were investigated by means of a Fourier transform infrared (FTIR) spectroscopic analysis, as well as by the characteristics of the removal under different treatment conditions.
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Affiliation(s)
- Koreyoshi Imamura
- Department of Bioscience and Biotechnology, Faculty of Engineering, Okayama University, Okayama 700-8530, Japan.
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Nayak P, Talwar S, Major S, Srinivasa R. Effect of cadmium arachidate on molecular packing of zinc arachidate LB multilayers. Colloids Surf A Physicochem Eng Asp 2006. [DOI: 10.1016/j.colsurfa.2005.10.046] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Dong WF, Wang R, Mao G, Möhwald H. Self-assembled molecular patterns of fatty acid on graphite in the presence of metal ions. SOFT MATTER 2006; 2:686-692. [PMID: 32680226 DOI: 10.1039/b604213a] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The stripe phase formed by long-chain alkane derivatives on the graphite lattice provides a unique opportunity for the study of molecular adsorption, aggregation, and reaction on patterns. Fatty acids, such as arachidic acid (AA), self-assemble on graphite into a sheet of parallel stripes with a periodicity of twice its molecular chain length. The molecular pattern is thus defined precisely by the size and functionality of the headgroup and tailgroup of the amphiphile. Complexation of metal ions to AA fixes the number and location of the ion, which can serve as a precursor to semiconductor nanocrystal arrays. In order to understand the effect of the ion complexation, we carry out atomic force microscopy (AFM) and Fourier transform infrared spectroscopy (FTIR) investigations of AA self-assembly in the presence of various metal ions. While the stripe orientation is dictated by the graphite lattice and the stripe periodicity is determined by the AA chain length, the size, shape, and degree of order of the stripe crystalline domain are influenced by the metal ion bond strength to the carboxylic ligand. The change of morphology in the self-assembled pattern shows a trend along the Irving-Williams series.
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Affiliation(s)
- Wen-Fei Dong
- Key Laboratory of Automobile Materials (Jilin University), Ministry of Education and Department of Materials Science and Engineering, Jilin University, Changchun, 130025, China and Max Planck Institute of Colloids and Interfaces, Golm/Potsdam, D-14476, Germany
| | - Ruomiao Wang
- Department of Chemical Engineering and Materials Science, Wayne State University, 5050 Anthony Wayne Drive, Detroit, Michigan 48202, USA.
| | - Guangzhao Mao
- Department of Chemical Engineering and Materials Science, Wayne State University, 5050 Anthony Wayne Drive, Detroit, Michigan 48202, USA.
| | - Helmuth Möhwald
- Max Planck Institute of Colloids and Interfaces, Golm/Potsdam, D-14476, Germany
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Sulaiman K, Majid WHA, Muhamad MR. Molecular Orientation of Phospholipid Langmuir-Blodgett Films. MATERIALS SCIENCE FORUM 2006; 517:65-68. [DOI: 10.4028/www.scientific.net/msf.517.65] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/01/2023]
Abstract
The molecular organization of the phospholipids Langmuir-Blodgett (LB) films on solid
substrates has been studied via Fourier Transform Infra Red (FTIR) spectroscopy. In this study, the
formation of well organized ultra thin LB films of phospholipid molecules has been performed by
depositing the monolayer onto the solid substrates of silicon wafer. The space filling molecular
models of two types of phospholipids have been proposed on the basis of the FTIR spectra.
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Dynarowicz Łatka P, Pérez-Morales M, Muñoz E, Broniatowski M, Martín-Romero MT, Camacho L. Structural Investigation of Langmuir and Langmuir−Blodgett Monolayers of Semifluorinated Alkanes. J Phys Chem B 2006; 110:6095-100. [PMID: 16553421 DOI: 10.1021/jp057270u] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The behavior of a semi-fluorinated alkane (C(10)F(21)C(19)H(39)) has been studied at the air-water interface by using surface pressure and surface potential-area isotherms as well as infrared spectroscopy for the Langmuir-Blodgett films. In addition, based on the quantum chemical PM3 semiempirical approach, the dimer structure was investigated, and the double helix was found to be the most stable conformation of the dimer. The obtained results allow us to imply that the phase transition observed in the course of the surface pressure/area isotherm is due to a conformational change originating from the double helix to a vertical, single helix configuration.
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Affiliation(s)
- Patrycja Dynarowicz Łatka
- Departamento de Química Física y Termodinamica Aplicada, Universidad de Córdoba, Campus Universitario de Rabanales, Ed. Marie Curie, E-14071 Córdoba, Spain.
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Nagayasu T, Imamura K, Nakanishi K. Adsorption characteristics of various organic substances on the surfaces of tantalum, titanium, and zirconium. J Colloid Interface Sci 2005; 286:462-70. [PMID: 15897059 DOI: 10.1016/j.jcis.2005.01.023] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2004] [Accepted: 01/18/2005] [Indexed: 11/15/2022]
Abstract
Adsorption characteristics of carboxylic acids, amines, an octapeptide composed of four L-alanine and four L-aspartic acid residues (Peptide-A4D4), and beta-lactoglobulin (beta-Lg) on tantalum (Ta), titanium (Ti), and zirconium (Zr) particles were examined at 30 degrees C and in some case, were compared with their adsorption onto SUS316L stainless steel particles (S6L). The adsorption isotherms on the Ta, Ti, and Zr particles could usually be expressed either by a Langmuir-type equation for reversible adsorption or by a modified Langmuir-type adsorption equation including terms for both reversible and irreversible adsorption. The adsorption equilibrium of benzoic acid, benzylamine, and m-xylylenediamine on all the metal surfaces followed a Langmuir-type equation, while those of phthalic acid, mellitic acid, and Peptide-A4D4 could be fitted to the modified Langmuir-type adsorption equation. The adsorption characteristics of different adsorbates on the different surfaces were discussed particularly with reference to the pH dependencies of the q(irrev), q(rev), and K values and the electrostatic properties of the oxidized surface of the metal particles. Fourier transform infrared spectroscopic analyses using a reflection/absorption technique (RA-IR) indicated that phthalic acid and mellitic acid are adsorbed in similar adsorption states irrespective of the type of metal. beta-Lg was adsorbed onto the surfaces principally in an irreversible manner. The desorption behavior of beta-Lg from Ta, Ti, and S6L surfaces was examined, in order to evaluate the extent of interaction between beta-Lg and the metals.
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Affiliation(s)
- Takeshi Nagayasu
- Department of Bioscience and Biotechnology, Faculty of Engineering, Okayama University, 3-1-1 Tsushima-naka, Okayama 700-8530, Japan
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Nanocrystalline CuO films prepared by pyrolysis of Cu-arachidate LB multilayers. Colloids Surf A Physicochem Eng Asp 2005. [DOI: 10.1016/j.colsurfa.2004.10.029] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Kumar NP, Major S, Vitta S, Talwar S, Gupta A, Dasannacharya B. Structure of polymorphic phases in zinc arachidate LB multilayers. Colloids Surf A Physicochem Eng Asp 2005. [DOI: 10.1016/j.colsurfa.2004.10.033] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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39
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Parhizkar M, Kumar N, Nayak P, Talwar S, Major S, Srinivasa R. CdxZn1−xS–arachidic acid composite LB films. Colloids Surf A Physicochem Eng Asp 2005. [DOI: 10.1016/j.colsurfa.2004.10.031] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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41
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Parhizkar M, Kumar N, Nayak P, Singh S, Talwar S, Major S, Srinivasa R. Nanocrystalline ZnO films prepared by pyrolysis of Zn-arachidate LB multilayers. Colloids Surf A Physicochem Eng Asp 2005. [DOI: 10.1016/j.colsurfa.2004.10.040] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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de Miguel G, Pedrosa JM, Martín-Romero MT, Muñoz E, Richardson TH, Camacho L. Conformational Changes of a Calix[8]arene Derivative at the Air−Water Interface. J Phys Chem B 2005; 109:3998-4006. [PMID: 16851456 DOI: 10.1021/jp045857n] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The particular behavior of a p-tert-butyl calix[8]arene derivative (C8A) has been studied at the air-water interface using surface pressure-area isotherms, surface potential-area isotherms, film relaxation measurements, Brewster angle microscopy (BAM), and infrared spectroscopy for Langmuir-Blodgett films. Thus, it is observed that the properties of the film, for example, isotherms, domain formation, and FTIR spectra, recorded during the first compression cycle differ appreciably from those during the second compression and following cycles. The results obtained are interpreted on the basis of the conformational changes of the C8A molecules by surface pressure, allowing us to inquire into the inter- and intramolecular interactions (hydrogen bonds) of those molecules. Thus, the compression induces changes in the kind of hydrogen bonds from intra- and intermolecular with other C8A molecules to hydrogen bonds with water molecules.
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Affiliation(s)
- Gustavo de Miguel
- Departamento de Química Física y Termodinamica Aplicada, Universidad de Córdoba, Campus Universitario de Rabanales, Ed. Marie Curie, E-14071 Córdoba, Spain
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Nakazawa T, Azumi R, Sakai H, Abe M, Matsumoto M. Control of photoreaction of amphiphilic spiropyran/n-alkane Langmuir and Langmuir-Blodgett films using the phase transition of n-alkane. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2004; 20:10583-10590. [PMID: 15544388 DOI: 10.1021/la0482857] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The structures and photoreactions of Langmuir and Langmuir-Blodgett (LB) films of an amphiphilic spiropyran, 1',3'-dihydro-3',3'-dimethyl-6-nitro-1'-octadecyl-8-(docosanoyloxymethyl)spiro[2H-1-benzopyran-2,2'-(2H)-indole] (SP), mixed with n-alkane are investigated. The mixing ratio was fixed at 1/2 for SP/n-alkane. The surface pressure-area isotherms of SP/octadecane are categorized into two regimes: a low-temperature regime where octadecane is packed with the alkyl chains of SP, and a high-temperature regime where the addition of octadecane does not influence the isotherms significantly. The temperature dividing the two regimes is related with the melting point of the n-alkane mixed with SP in the bulk. UV irradiation of the Langmuir film in the high-temperature regime gives rise to light-induced J-aggregation, whereas that in the low-temperature regime causes only the isomerization of SP to the corresponding merocyanine, indicating that J-aggregation is hindered by the presence of n-alkane in the low-temperature regime. IR external reflection spectroscopy of the Langmuir films shows that n-alkane is released from the film during J-aggregation. The structural changes of the mixed Langmuir and LB films during J-aggregation are almost the same with those of the films of pure SP.
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Affiliation(s)
- Takahiro Nakazawa
- Faculty of Science and Technology, Tokyo University of Science, 2641 Yamazaki, Noda 278-8510, Japan
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Nagayasu T, Yoshioka C, Imamura K, Nakanishi K. Effects of carboxyl groups on the adsorption behavior of low-molecular-weight substances on a stainless steel surface. J Colloid Interface Sci 2004; 279:296-306. [PMID: 15464793 DOI: 10.1016/j.jcis.2004.06.081] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2003] [Accepted: 06/27/2004] [Indexed: 11/22/2022]
Abstract
The adsorption isotherms of various carboxylic acids and several amines on a stainless steel surface were taken as a function of pH and the ionic strength of the solution at 30 degrees C. In particular, the effect of the number of carboxyl groups on the adsorption behavior was investigated. Monocarboxylic acids such as benzoic acid and n-butyric acid were reversibly adsorbed on the stainless steel particles and showed a Langmuir-type adsorption isotherm, i.e., Q=KqmC/(1+KC), where Q and C are, respectively, the amount of adsorbate adsorbed and the equilibrium concentration in the bulk solution, qm, the maximum adsorbed amount, and K is the adsorption equilibrium constant. Carboxylic acids having plural carboxyl groups had much higher affinity to the surface and were adsorbed in both reversible and irreversible modes. The adsorption isotherms for the carboxylic acids having plural carboxyl groups could be expressed by a modified Langmuir-type adsorption isotherm, i.e., Q=q(irrev)+Kq(rev)C/(1+KC), where q(irrev) and q(rev) are, respectively, the maximum amounts adsorbed irreversibly and reversibly. The K and q(irrev) values increased with an increase in the number of carboxyl groups except for isophthalic acid and terephthalic acid. On the basis of the pH dependencies of K, qm, q(irrev), and q(rev) as well as the surface properties of the stainless steel, both reversible and irreversible adsorptions were considered to occur through the electrostatic interaction between negatively charged carboxyl groups and the positively charged sites on the surface. The dependency of the q(irrev) value on ionic strength was discussed on the basis of the differences in their adsorbed state with the interaction forces to the surface and repulsive forces among the adsorbed molecules. The adsorption of amine components was quite weak. The RA-IR and molecular dynamics calculation were done to investigate the adsorption states of phthalic acid, trimellitic acid, and mellitic acid.
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Affiliation(s)
- Takeshi Nagayasu
- Department of Bioscience and Biotechnology, Faculty of Engineering, Okayama University, 3-1-1 Tsushima-naka, Okayama 700-8530, Japan
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Matsumoto M, Tanaka KI, Azumi R, Kondo Y, Yoshino N. Template-directed patterning using phase-separated Langmuir-Blodgett films. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2004; 20:8728-8734. [PMID: 15379499 DOI: 10.1021/la0488250] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The structures of the mixed Langmuir-Blodgett (LB) films of conventional amphiphiles (CAs) and amphiphilic silane-coupling agents (SCAs) were investigated using IR spectroscopy, atomic force microscopy, and friction force microscopy. By using CAs having hydrogenated alkyl chains and SCAs having perfluorinated alkyl chains, phase-separated structures were formed with domains consisting of CAs surrounded by SCAs. The size and shape of the domains depended strongly on the mixed components, the mixing ratios, and the subphase temperature. In particular, usage of a CA having hydrogenated and perfluorinated portions in the hydrophobic group as one of the components led to the formation of nanothreads. When the phase-separated mixed LB films were heated, SCAs formed covalent bonds with the substrates having silanol groups whereas CAs did not have such ability. Rinsing the heat-treated LB films with ethanol selectively removed CAs with the SCA regions intact, resulting in the fabrication of templates. The structures of the templates reflected those of the original phase-separated LB films. LB transfer of amphiphiles on the templates led to the confinement of the amphiphiles in regions with the size and shape delineated by the templates. These results demonstrate that a variety of amphiphiles can be confined two-dimensionally in a designed manner.
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Affiliation(s)
- Mutsuyoshi Matsumoto
- Nanotechnology Research Institute, National Institute of Advanced Industrial Science and Technology, Tsukuba Central 5-2, 1-1-1 Higashi, 305-8565, Japan.
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Gole A, Orendorff CJ, Murphy CJ. Immobilization of gold nanorods onto acid-terminated self-assembled monolayers via electrostatic interactions. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2004; 20:7117-7122. [PMID: 15301495 DOI: 10.1021/la049051q] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
We report the immobilization of gold nanorods onto self-assembled monolayers (SAMs) of 16-mercaptohexadecanoic acid (16-MHA). The simple two step protocol involves formation of a SAM of 16-MHA molecules onto gold-coated glass slides and subsequent immersion of these slides into the gold nanorod solution. The nanorods, formed by a seed-mediated, surfactant-assisted synthesis protocol, are stabilized in solution due to surface modification by the surfactant cetyltrimethylammonium bromide (CTAB). Attractive electrostatic interactions between the carboxylic acid group on the SAM and the positively charged CTAB molecules are likely responsible for the nanorod immobilization. UV-vis spectroscopy has been used to follow the kinetics of the nanorod immobilization. The nature of interaction between the gold nanorods and the 16-MHA SAM has been probed by Fourier transform infrared spectroscopy (FTIR). The surface morphology of the immobilized rods is studied by scanning electron microscopy (SEM) and atomic force microscopy (AFM) measurements. SEM was also used to determine the density of the immobilized nanorods as a function of the pH of immobilization. Control over the surface coverage of the immobilized gold nanorods has been demonstrated by simple pH variation. Such well-dispersed immobilized gold nanorods with control over the surface coverage could be interesting substrates for applications such as surface-enhanced Raman spectroscopy (SERS).
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Affiliation(s)
- Anand Gole
- Department of Chemistry and Biochemistry, University of South Carolina, Columbia, South Carolina 29208, USA
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Zawisza I, Bin X, Lipkowski J. Spectroelectrochemical studies of bilayers of phospholipids in gel and liquid state on Au(111) electrode surface. Bioelectrochemistry 2004; 63:137-47. [PMID: 15110264 DOI: 10.1016/j.bioelechem.2003.12.004] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2003] [Revised: 11/28/2003] [Accepted: 12/03/2003] [Indexed: 11/29/2022]
Abstract
Differential capacity, chronocoulometry and Polarization Modulation Fourier Transform Infrared Reflection Absorption Spectroscopy (PM FTIRRAS) were employed to investigate spreading of small unilamellar vesicles (SUVs) of DOPC and DMPC onto a Au(111) electrode surface. The electrochemical experiments demonstrated that vesicles fuse onto the electrode surface and at E>-0.5V (SSCE) or at charge densities -10<sigma(M)<5 microC cm(-2) to form defected bilayers, directly in contact with the metal surface. The analysis of PM FTIRRA spectra in the CH stretching region showed that the DOPC bilayer is in the liquid crystalline state while the bilayer of DMPC is in the gel or in the ripple phase. The spectra were also used to determine the tilt of the acyl chains in the bilayer of DMPC as a function of the electrode potential. At E<-0.5 V (SSCE), where the bilayer is detached from the metal surface, the chains are tilted at approximately 29 degrees with respect to surface normal. When the bilayer is adsorbed at the metal surface at E>-0.5 V (SSCE), the tilt angle increases to approximately 42 degrees. The increase of the tilt angle is discussed in terms of a change in the packing of the polar head of the phospholipids molecules in the bilayer adsorbed at the electrode surface.
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Affiliation(s)
- Izabella Zawisza
- Department of Chemistry and Biochemistry, University of Guelph, Guelph, Ontario, Canada N1G2W1
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Akutagawa T, Kakiuchi K, Hasegawa T, Nakamura T, Christensen CA, Becher J. Langmuir-Blodgett films of amphiphilic bis(tetrathiafulvalene) macrocycles with four alkyl chains. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2004; 20:4187-95. [PMID: 15969416 DOI: 10.1021/la049950e] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Amphiphilic bis(tetrathiafulvalene) [bis(TTF)] macrocycles with four alkyl chains were fabricated as novel electrically active Langmuir-Blodgett (LB) films. Two TTF units were linked via [24]crown-8, [21]crown-7, and [18]crown-6 macrocycles, forming charge-transfer (CT) salts with 2,3,5,6-tetrafluoro-7,7,8,8-tetracyano-p-quinodimethane (F4-TCNQ) at the air-water interface and on solid substrates. The CT salt of the amphiphilic bis(TTF)-macrocycle having a [24]crown-8 ring system formed a uniform surface morphology on mica. Using single-crystal X-ray structural analysis, the layer structure between the hydrophobic chains and the one-dimensional pi-pi stack of the CT salt was confirmed. Our results show that the bis(TTF)-macrocycle was folded at the flexible [24]crown-8 moiety, forming intramolecular pi-pi dimer structures and one-dimensional intermolecular pi-pi stacks with F4-TCNQ dimers. The open-shell electronic structure of the LB films was determined by electronic spectra, electrical conductivity, and electron spin resonance analyses. Asymmetry was introduced into the bis(TTF)-macrocycle by changing the ring size from [24]crown-8 to [21]crown-7. The surface morphology of the CT salts with F4-TCNQ was established as two-dimensional round-shape domains on mica. Further reduction of the macrocyclic ring from [21]crown-7 to [18]crown-6 resulted in a CT salt of the bis(TTF)-macrocycle with F4-TCNQ with a leaf-shape domain morphology and a typical dimension of approximately 1 microm2 on mica. In general, decreasing the macrocyclic ring size from [24]crown-8 to [21]crown-7 or [18]crown-6 affected the inter- and intramolecular interactions and the surface morphologies of LB films.
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Affiliation(s)
- Tomoyuki Akutagawa
- Research Institute for Electronic Science, Hokkaido University, Sapporo 060-0812, Japan.
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Pelletier I, Laurin I, Buffeteau T, Pézolet M. Determination of Molecular Orientation in Biaxially Oriented Ultrathin Films. J Phys Chem B 2004. [DOI: 10.1021/jp036221j] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Isabelle Pelletier
- Centre de Recherche en Science et Ingénierie des Macromolécules, Département de Chimie, Université Laval, Québec, Qc, G1K 7P4, Canada, and Laboratoire de Physico-Chimie Moléculaire, UMR 5803 du CNRS, Université Bordeaux I, 33405 Talence, France
| | - Isabelle Laurin
- Centre de Recherche en Science et Ingénierie des Macromolécules, Département de Chimie, Université Laval, Québec, Qc, G1K 7P4, Canada, and Laboratoire de Physico-Chimie Moléculaire, UMR 5803 du CNRS, Université Bordeaux I, 33405 Talence, France
| | - Thierry Buffeteau
- Centre de Recherche en Science et Ingénierie des Macromolécules, Département de Chimie, Université Laval, Québec, Qc, G1K 7P4, Canada, and Laboratoire de Physico-Chimie Moléculaire, UMR 5803 du CNRS, Université Bordeaux I, 33405 Talence, France
| | - Michel Pézolet
- Centre de Recherche en Science et Ingénierie des Macromolécules, Département de Chimie, Université Laval, Québec, Qc, G1K 7P4, Canada, and Laboratoire de Physico-Chimie Moléculaire, UMR 5803 du CNRS, Université Bordeaux I, 33405 Talence, France
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