Pub Date : 2015-01-01DOI: 10.1007/978-1-4939-2425-7
C. L. Meyerkord, H. Fu
{"title":"Protein-Protein Interactions","authors":"C. L. Meyerkord, H. Fu","doi":"10.1007/978-1-4939-2425-7","DOIUrl":"https://doi.org/10.1007/978-1-4939-2425-7","url":null,"abstract":"","PeriodicalId":58,"journal":{"name":"The Journal of Physical Chemistry ","volume":null,"pages":null},"PeriodicalIF":2.781,"publicationDate":"2015-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76406061","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
M. Natali, M. Ravaglia, F. Scandola, J. Boixel, Y. Pellegrin, E. Blart, F. Odobel
New dyad and triad systems based on a zinc porphyrin (ZnP), a naphthalenediimide (NDI), and a ferrocene (Fc) as molecular components, linked by 1,2,3-triazole bridges, ZnP-NDI (3) and Fc-ZnP-NDI (4), have been synthesized. Their photophysical behavior has been investigated by both visible excitation of the ZnP chromophore and UV excitation of the NDI unit. Dyad 3 exhibits relatively inefficient quenching of the ZnP singlet excited state, slow charge separation, and fast charge recombination processes. Excitation of the NDI chromophore, on the other hand, leads to charge separation by both singlet and triplet quenching pathways, with the singlet charge-separated (CS) state recombining in a subnanosecond time scale and the triplet CS state decaying in ca. 90 ns. In the triad system 4, primary formation of the Fc-ZnP+-NDI- charge-separated state is followed by a secondary hole shift process from ZnP to Fc. The product of the stepwise charge separation, Fc+-ZnP-NDI-, undergoes recombination to the ground state in 1.9 μs. The charge-separated states are always formed more efficiently upon NDI excitation than upon ZnP excitation. DFT calculations on a bridge-acceptor fragment show that the bridge is expected to mediate a fast donor-to-bridge-to-acceptor electron cascade following excitation of the acceptor. More generally, triazole bridges may behave asymmetrically with respect to photoinduced electron transfer in dyads, kinetically favoring hole-transfer pathways triggered by excitation of the acceptor over electron-transfer pathways promoted by excitation of the donor.
以卟啉锌(ZnP)、萘二酰亚胺(NDI)和二茂铁(Fc)为分子组分，通过1,2,3-三唑桥连接，合成了ZnP-NDI(3)和Fc-ZnP-NDI(4)的二联体和三联体体系。通过ZnP发色团的可见光激发和NDI单元的紫外激发，研究了它们的光物理行为。Dyad 3表现出相对低效的ZnP单线态猝灭、缓慢的电荷分离和快速的电荷复合过程。另一方面，NDI发色团的激发通过单线态和三重态猝灭途径导致电荷分离，单线态电荷分离(CS)态在亚纳秒时间尺度内重组，三重态CS态在约90 ns内衰减。在三元体系4中，Fc-ZnP+- ndi -电荷分离态的初级形成伴随着从ZnP到Fc的二次空穴移位过程。分步电荷分离的产物Fc+- znp - ndi -在1.9 μs内重新组合到基态。NDI激发总是比ZnP激发更有效地形成电荷分离态。对桥-受体片段的DFT计算表明，在受体激发后，桥有望介导快速的供体-桥-受体电子级联。更一般地说，三唑桥在二偶体中可能表现出不对称的光诱导电子转移，动力学上倾向于由受体激发引发的空穴转移途径，而不是由供体激发促进的电子转移途径。
{"title":"Long-Range Charge Separation in a Ferrocene-(zinc Porphyrin)-Naphtalenediimide Triad. Asymmetric Role of 1,2,3-Triazole Linkers","authors":"M. Natali, M. Ravaglia, F. Scandola, J. Boixel, Y. Pellegrin, E. Blart, F. Odobel","doi":"10.1021/JP406405K","DOIUrl":"https://doi.org/10.1021/JP406405K","url":null,"abstract":"New dyad and triad systems based on a zinc porphyrin (ZnP), a naphthalenediimide (NDI), and a ferrocene (Fc) as molecular components, linked by 1,2,3-triazole bridges, ZnP-NDI (3) and Fc-ZnP-NDI (4), have been synthesized. Their photophysical behavior has been investigated by both visible excitation of the ZnP chromophore and UV excitation of the NDI unit. Dyad 3 exhibits relatively inefficient quenching of the ZnP singlet excited state, slow charge separation, and fast charge recombination processes. Excitation of the NDI chromophore, on the other hand, leads to charge separation by both singlet and triplet quenching pathways, with the singlet charge-separated (CS) state recombining in a subnanosecond time scale and the triplet CS state decaying in ca. 90 ns. In the triad system 4, primary formation of the Fc-ZnP+-NDI- charge-separated state is followed by a secondary hole shift process from ZnP to Fc. The product of the stepwise charge separation, Fc+-ZnP-NDI-, undergoes recombination to the ground state in 1.9 μs. The charge-separated states are always formed more efficiently upon NDI excitation than upon ZnP excitation. DFT calculations on a bridge-acceptor fragment show that the bridge is expected to mediate a fast donor-to-bridge-to-acceptor electron cascade following excitation of the acceptor. More generally, triazole bridges may behave asymmetrically with respect to photoinduced electron transfer in dyads, kinetically favoring hole-transfer pathways triggered by excitation of the acceptor over electron-transfer pathways promoted by excitation of the donor.","PeriodicalId":58,"journal":{"name":"The Journal of Physical Chemistry ","volume":null,"pages":null},"PeriodicalIF":2.781,"publicationDate":"2013-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79834243","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Taking advantage of surfaces’ response to interfacial dipoles, a class of photochromophores (dihydroindolizine) is demonstrated to alter the work function of the underlying substrate (∼170 meV). This same molecule also provides spectroscopic signatures for correlating the change in molecular structure to the induced change in the surfaces’ electronic properties. Polarization modulation infrared reflection absorption spectroscopy (PM-IRRAS) allows analysis of the characteristic dihydroindolizine C═C (1559 cm–1) and pyridinium (1643 cm–1) stretch as a function of photoexcitation. Structural assignments of this photochromophore are corroborated to density function theory calculations. Conformational changes in the monolayers appear in parallel with work function changes and are consistent with both its rate and magnitude.
利用表面对界面偶极子的响应，一类光发色团(二氢吲哚嗪)被证明可以改变衬底的功函数(~ 170 meV)。这个分子还提供了光谱特征，将分子结构的变化与表面电子性质的诱导变化联系起来。偏振调制红外反射吸收光谱(PM-IRRAS)允许分析二氢吲哚嗪C = C (1559 cm-1)和吡啶(1643 cm-1)作为光激发函数的特征拉伸。该光发色团的结构分配得到密度函数理论计算的证实。单分子层的构象变化与功函数变化平行，且与功函数变化的速率和幅度一致。
{"title":"Spectroscopic Evidence of Work Function Alterations Due to Photoswitchable Monolayers on Gold Surfaces","authors":"Matthew A. Bartucci, J. Florián, J. Ciszek","doi":"10.1021/JP405710U","DOIUrl":"https://doi.org/10.1021/JP405710U","url":null,"abstract":"Taking advantage of surfaces’ response to interfacial dipoles, a class of photochromophores (dihydroindolizine) is demonstrated to alter the work function of the underlying substrate (∼170 meV). This same molecule also provides spectroscopic signatures for correlating the change in molecular structure to the induced change in the surfaces’ electronic properties. Polarization modulation infrared reflection absorption spectroscopy (PM-IRRAS) allows analysis of the characteristic dihydroindolizine C═C (1559 cm–1) and pyridinium (1643 cm–1) stretch as a function of photoexcitation. Structural assignments of this photochromophore are corroborated to density function theory calculations. Conformational changes in the monolayers appear in parallel with work function changes and are consistent with both its rate and magnitude.","PeriodicalId":58,"journal":{"name":"The Journal of Physical Chemistry ","volume":null,"pages":null},"PeriodicalIF":2.781,"publicationDate":"2013-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76980196","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Energetics of carboxyl groups at the periphery of a graphene sheet are studied using density functional theory (B3LYP) with a 6-31G* basis set, augmented with diffuse functions on O. Corner sites are energetically preferred followed by zigzag edges, and armchair edges are least stable. The energy and geometry of each is attributed to a competition between π-conjugation and steric repulsion factors. Vibrational analyses reveal certain features that are characteristic of each site location, which may help in the assignment of experimental spectra of graphene and other polycyclic aromatic hydrocarbons. For example, zigzag sites typically lead to an intense C═O stretching band that occurs below 1700 cm–1, quite uncommon for the carboxyl group.
{"title":"Site Preferences of Carboxyl Groups on the Periphery of Graphene and their Characteristic IR Spectra","authors":"T. Kar, S. Scheiner, U. Adhikari, A. Roy","doi":"10.1021/JP403728B","DOIUrl":"https://doi.org/10.1021/JP403728B","url":null,"abstract":"Energetics of carboxyl groups at the periphery of a graphene sheet are studied using density functional theory (B3LYP) with a 6-31G* basis set, augmented with diffuse functions on O. Corner sites are energetically preferred followed by zigzag edges, and armchair edges are least stable. The energy and geometry of each is attributed to a competition between π-conjugation and steric repulsion factors. Vibrational analyses reveal certain features that are characteristic of each site location, which may help in the assignment of experimental spectra of graphene and other polycyclic aromatic hydrocarbons. For example, zigzag sites typically lead to an intense C═O stretching band that occurs below 1700 cm–1, quite uncommon for the carboxyl group.","PeriodicalId":58,"journal":{"name":"The Journal of Physical Chemistry ","volume":null,"pages":null},"PeriodicalIF":2.781,"publicationDate":"2013-08-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89533020","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
C. Hahn, A. Cordones, Sean Andrews, Hanwei Gao, Anthony Fu, S. Leone, Peidong Yang
The utility of an annealing procedure in ammonia ambient is investigated for improving the optical characteristics of InxGa1–xN nanowires (0.07 ≤ x ≤ 0.42) grown on c-Al2O3 using a halide chemical vapor deposition method. Morphological studies using scanning electron microscopy confirm that the nanowire morphology is retained after annealing in ammonia at temperatures up to 800 °C. However, significant indium etching and composition inhomogeneities are observed for higher indium composition nanowires (x = 0.28, 0.42), as measured by energy-dispersive X-ray spectroscopy and Z-contrast scanning transmission electron microscopy. Structural analyses, using X-ray diffraction and high-resolution transmission electron microscopy, indicate that this is a result of the greater thermal instability of higher indium composition nanowires. The effect of these structural changes on the optical quality of InGaN nanowires is examined using steady-state and time-resolved photoluminescence measurements. Annealing in ammoni...
{"title":"Effect of Thermal Annealing in Ammonia on the Properties of InGaN Nanowires with Different Indium Concentrations","authors":"C. Hahn, A. Cordones, Sean Andrews, Hanwei Gao, Anthony Fu, S. Leone, Peidong Yang","doi":"10.1021/JP311685X","DOIUrl":"https://doi.org/10.1021/JP311685X","url":null,"abstract":"The utility of an annealing procedure in ammonia ambient is investigated for improving the optical characteristics of InxGa1–xN nanowires (0.07 ≤ x ≤ 0.42) grown on c-Al2O3 using a halide chemical vapor deposition method. Morphological studies using scanning electron microscopy confirm that the nanowire morphology is retained after annealing in ammonia at temperatures up to 800 °C. However, significant indium etching and composition inhomogeneities are observed for higher indium composition nanowires (x = 0.28, 0.42), as measured by energy-dispersive X-ray spectroscopy and Z-contrast scanning transmission electron microscopy. Structural analyses, using X-ray diffraction and high-resolution transmission electron microscopy, indicate that this is a result of the greater thermal instability of higher indium composition nanowires. The effect of these structural changes on the optical quality of InGaN nanowires is examined using steady-state and time-resolved photoluminescence measurements. Annealing in ammoni...","PeriodicalId":58,"journal":{"name":"The Journal of Physical Chemistry ","volume":null,"pages":null},"PeriodicalIF":2.781,"publicationDate":"2013-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81230808","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
F. Fayon, C. Duee, Thomas Poumeyrol, M. Allix, D. Massiot
Bioactive glasses are able to form strong bonds to bone. This property, crucial for medical applications, depends on the glass composition and structure. Dissolution of phosphates in melt-quenched silicate glasses raises the question of chemical homogeneity and possible formation of clusters. A detailed structural characterization of the bioactive glasses is thus highly desirable. In this work, the nature of the distribution of phosphate units in a melt-quenched bioactive glass is elucidated for the first time using 31P spin-counting solid-state NMR experiments. The structure of a dense bioactive calcium silicate glass with 2.6 mol % of phosphorus oxide is shown to exhibit nanometric-sized chemical and structural heterogeneities. Clear experimental evidence of the presence of phosphate clusters of five and six PO4 tetrahedral units embedded in the disordered polymeric silicate network is given.
{"title":"Evidence of Nanometric-Sized Phosphate Clusters in Bioactive Glasses As Revealed by Solid-State 31P NMR","authors":"F. Fayon, C. Duee, Thomas Poumeyrol, M. Allix, D. Massiot","doi":"10.1021/JP312263J","DOIUrl":"https://doi.org/10.1021/JP312263J","url":null,"abstract":"Bioactive glasses are able to form strong bonds to bone. This property, crucial for medical applications, depends on the glass composition and structure. Dissolution of phosphates in melt-quenched silicate glasses raises the question of chemical homogeneity and possible formation of clusters. A detailed structural characterization of the bioactive glasses is thus highly desirable. In this work, the nature of the distribution of phosphate units in a melt-quenched bioactive glass is elucidated for the first time using 31P spin-counting solid-state NMR experiments. The structure of a dense bioactive calcium silicate glass with 2.6 mol % of phosphorus oxide is shown to exhibit nanometric-sized chemical and structural heterogeneities. Clear experimental evidence of the presence of phosphate clusters of five and six PO4 tetrahedral units embedded in the disordered polymeric silicate network is given.","PeriodicalId":58,"journal":{"name":"The Journal of Physical Chemistry ","volume":null,"pages":null},"PeriodicalIF":2.781,"publicationDate":"2013-01-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72617461","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
We review recent ab initio molecular dynamics studies of electrode/electrolyte interfaces in lithium ion batteries. Our goals are to introduce experimentalists to simulation techniques applicable to models which are arguably most faithful to experimental conditions so far, and to emphasize to theorists that the inherently interdisciplinary nature of this subject requires bridging the gap between solid and liquid state perspectives. We consider liquid ethylene carbonate (EC) decomposition on lithium intercalated graphite, lithium metal, oxide-coated graphite, and spinel manganese oxide surfaces. These calculations are put in the context of more widely studied water–solid interfaces. Our main themes include kinetically controlled two-electron-induced reactions, the breaking of a previously much neglected chemical bond in EC, and electron tunneling. Future work on modeling batteries at atomic length scales requires capabilities beyond state-of-the-art, which emphasizes that applied battery research can and s...
{"title":"Electronic Structure Modeling of Electrochemical Reactions at Electrode/Electrolyte Interfaces in Lithium Ion Batteries","authors":"K. Leung","doi":"10.1021/jp308929a","DOIUrl":"https://doi.org/10.1021/jp308929a","url":null,"abstract":"We review recent ab initio molecular dynamics studies of electrode/electrolyte interfaces in lithium ion batteries. Our goals are to introduce experimentalists to simulation techniques applicable to models which are arguably most faithful to experimental conditions so far, and to emphasize to theorists that the inherently interdisciplinary nature of this subject requires bridging the gap between solid and liquid state perspectives. We consider liquid ethylene carbonate (EC) decomposition on lithium intercalated graphite, lithium metal, oxide-coated graphite, and spinel manganese oxide surfaces. These calculations are put in the context of more widely studied water–solid interfaces. Our main themes include kinetically controlled two-electron-induced reactions, the breaking of a previously much neglected chemical bond in EC, and electron tunneling. Future work on modeling batteries at atomic length scales requires capabilities beyond state-of-the-art, which emphasizes that applied battery research can and s...","PeriodicalId":58,"journal":{"name":"The Journal of Physical Chemistry ","volume":null,"pages":null},"PeriodicalIF":2.781,"publicationDate":"2012-12-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85709203","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Vibrational frequency analysis using density functional theory resolves some ambiguities in interpretation of IR spectra of carboxylated single-wall carbon nanotubes (o-SWNTs). Armchair (n,n) and zigzag (m,0) tubes, with diameter varying between 0.5 and 1.4 nm, were populated with different numbers of COOH groups at one terminus. While armchair-COOH tubes exhibit C═O stretching frequencies in the standard range of 1720–1760 cm–1, zigzag-COOH tubes display a new C═O band around 1650 cm–1 with much higher intensity, in addition to the higher-frequency C═O mode. The COOH groups exhibiting this low-frequency (lf-COOH) are displaced well off the lines of the tube walls, to the outside. This new band is in the same range as one observed experimentally, which has on occasion been attributed to quinone formation. The C═O bond length in the relevant COOH groups is longer by about 0.01 A than regular C═O bonds. Such low-frequency C═O band is unusual and not common for any stand-alone COOH group and seems characteri...
{"title":"Unusual Low-Vibrational C═O Mode of COOH Can Distinguish between Carboxylated Zigzag and Armchair Single-Wall Carbon Nanotubes","authors":"T. Kar, S. Scheiner, A. Roy, H. Bettinger","doi":"10.1021/JP309699Z","DOIUrl":"https://doi.org/10.1021/JP309699Z","url":null,"abstract":"Vibrational frequency analysis using density functional theory resolves some ambiguities in interpretation of IR spectra of carboxylated single-wall carbon nanotubes (o-SWNTs). Armchair (n,n) and zigzag (m,0) tubes, with diameter varying between 0.5 and 1.4 nm, were populated with different numbers of COOH groups at one terminus. While armchair-COOH tubes exhibit C═O stretching frequencies in the standard range of 1720–1760 cm–1, zigzag-COOH tubes display a new C═O band around 1650 cm–1 with much higher intensity, in addition to the higher-frequency C═O mode. The COOH groups exhibiting this low-frequency (lf-COOH) are displaced well off the lines of the tube walls, to the outside. This new band is in the same range as one observed experimentally, which has on occasion been attributed to quinone formation. The C═O bond length in the relevant COOH groups is longer by about 0.01 A than regular C═O bonds. Such low-frequency C═O band is unusual and not common for any stand-alone COOH group and seems characteri...","PeriodicalId":58,"journal":{"name":"The Journal of Physical Chemistry ","volume":null,"pages":null},"PeriodicalIF":2.781,"publicationDate":"2012-11-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75621554","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Calculations of the full structure and spectra of large nanotubes can be very demanding of computer resources. The advantages and limitations of the cost-effective same level different basis (SLDB) and selected normal modes (SNM) protocols are elucidated for carboxylated (4,4) armchair and (8,0) zigzag single-wall carbon nanotubes (SWNTs) with varying numbers of COOH groups on the tips of the tubes. While armchair-COOH tubes exhibit C═O stretching frequencies in the standard range of 1720–1760 cm–1, zigzag-COOH tubes display a surprising C═O band around 1660 cm–1 with much higher intensity, in addition to the higher-frequency C═O mode. This low-frequency C═O peak is very unusual for a standalone COOH group and is a fingerprint of zigzag tubes.
{"title":"Reliability of Approximate Methods to Study Tip-Functionalized Single-Wall Carbon Nanotubes","authors":"T. Kar, S. Scheiner","doi":"10.1021/JP3089947","DOIUrl":"https://doi.org/10.1021/JP3089947","url":null,"abstract":"Calculations of the full structure and spectra of large nanotubes can be very demanding of computer resources. The advantages and limitations of the cost-effective same level different basis (SLDB) and selected normal modes (SNM) protocols are elucidated for carboxylated (4,4) armchair and (8,0) zigzag single-wall carbon nanotubes (SWNTs) with varying numbers of COOH groups on the tips of the tubes. While armchair-COOH tubes exhibit C═O stretching frequencies in the standard range of 1720–1760 cm–1, zigzag-COOH tubes display a surprising C═O band around 1660 cm–1 with much higher intensity, in addition to the higher-frequency C═O mode. This low-frequency C═O peak is very unusual for a standalone COOH group and is a fingerprint of zigzag tubes.","PeriodicalId":58,"journal":{"name":"The Journal of Physical Chemistry ","volume":null,"pages":null},"PeriodicalIF":2.781,"publicationDate":"2012-11-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86312736","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
P. Martins, C. Caparrós, R. Gonçalves, P. Martins, M. Benelmekki, G. Botelho, S. Lanceros‐Méndez
The electroactive β-phase of poly(vinylidene fluoride) (PVDF) can be nucleated by introducing CoFe2O4 nanoparticles within the polymer matrix, leading to electroactive materials with large potential for sensor and actuator applications. The effects of the CoFe2O4 nanoparticle electrostatic charge on the phase crystallization of PVDF polymer is reported. For this purpose, CoFe2O4 nanoparticles were coated with anionic (SDS), nonanionic (Triton X-100), and cationic (CTAB) surfactants, and the obtained coated nanoparticles were used as fillers. It is found that the piezoelectric β-form of the polymer increases when CoFe2O4 nanoparticles with higher negative electrostatic charge are added. This behavior is attributed to the interaction between the negatively charged magnetic particles and the polymer CH2 groups, having a positive charge density. Further the relationship between the β-phase content and the piezoelectric response has been demonstrated. The magnetostriction of the ferrite nanoparticles and the p...
{"title":"Role of Nanoparticle Surface Charge on the Nucleation of the Electroactive β-Poly(vinylidene fluoride) Nanocomposites for Sensor and Actuator Applications","authors":"P. Martins, C. Caparrós, R. Gonçalves, P. Martins, M. Benelmekki, G. Botelho, S. Lanceros‐Méndez","doi":"10.1021/JP3038768","DOIUrl":"https://doi.org/10.1021/JP3038768","url":null,"abstract":"The electroactive β-phase of poly(vinylidene fluoride) (PVDF) can be nucleated by introducing CoFe2O4 nanoparticles within the polymer matrix, leading to electroactive materials with large potential for sensor and actuator applications. The effects of the CoFe2O4 nanoparticle electrostatic charge on the phase crystallization of PVDF polymer is reported. For this purpose, CoFe2O4 nanoparticles were coated with anionic (SDS), nonanionic (Triton X-100), and cationic (CTAB) surfactants, and the obtained coated nanoparticles were used as fillers. It is found that the piezoelectric β-form of the polymer increases when CoFe2O4 nanoparticles with higher negative electrostatic charge are added. This behavior is attributed to the interaction between the negatively charged magnetic particles and the polymer CH2 groups, having a positive charge density. Further the relationship between the β-phase content and the piezoelectric response has been demonstrated. The magnetostriction of the ferrite nanoparticles and the p...","PeriodicalId":58,"journal":{"name":"The Journal of Physical Chemistry ","volume":null,"pages":null},"PeriodicalIF":2.781,"publicationDate":"2012-07-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82128513","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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