scholarly journals Thermodynamic and Kinetic Parameters for Calcite Nucleation on Peptoid and Model Scaffolds - a Step Toward Nacre Mimicry.

2019 ◽  
Author(s):  
Anne Rath Nielsen ◽  
Stanislav Jelavic ◽  
Daniel Murray ◽  
Behzad Rad ◽  
Martin Andersson ◽  
...  
Keyword(s):  
Free Energy ◽  
Calcium Carbonate ◽  
Kinetic Parameters ◽  
Functional Groups ◽  
Driving Forces ◽  
Interfacial Free Energy ◽  
Nucleation Theory ◽  
Dynamic Force ◽  
Thermodynamic And Kinetic Parameters ◽  
Insight Into

To establish an approach for a bulk upscaling of a composit material consisting of calcium carbonate and tunable peptoids we here combined three distinct approaches to thoroughly access the underlying kinetic and thermodynamic driving forces for CaCO3 formation on peptoid polymers. We derived the net interfacial free energy for calcite formation on the nanosheets and self-assemblage monolayers of the sheets constituent functional groups (carboxyl, amine and a 1:1 mix) using: nucleation experiments, dynamic force spectroscopy and theoretical modeling (COSMO-RS). We applied nucleation theory to the results and obtain insight into conditions were we can obtain favorable nucleation conditions on the polymers in a highly controlled manner.

scholarly journals Thermodynamic and Kinetic Parameters for Calcite Nucleation on Peptoid and Model Scaffolds - a Step Toward Nacre Mimicry.

2019 ◽  
Author(s):  
Anne Rath Nielsen ◽  
Stanislav Jelavic ◽  
Daniel Murray ◽  
Behzad Rad ◽  
Martin Andersson ◽  
...  
Keyword(s):  
Free Energy ◽  
Calcium Carbonate ◽  
Kinetic Parameters ◽  
Functional Groups ◽  
Driving Forces ◽  
Interfacial Free Energy ◽  
Nucleation Theory ◽  
Dynamic Force ◽  
Thermodynamic And Kinetic Parameters ◽  
Insight Into

To establish an approach for a bulk upscaling of a composit material consisting of calcium carbonate and tunable peptoids we here combined three distinct approaches to thoroughly access the underlying kinetic and thermodynamic driving forces for CaCO3 formation on peptoid polymers. We derived the net interfacial free energy for calcite formation on the nanosheets and self-assemblage monolayers of the sheets constituent functional groups (carboxyl, amine and a 1:1 mix) using: nucleation experiments, dynamic force spectroscopy and theoretical modeling (COSMO-RS). We applied nucleation theory to the results and obtain insight into conditions were we can obtain favorable nucleation conditions on the polymers in a highly controlled manner.

The origin of different driving forces between O–H/N–H functional groups in metal ligand cooperation: mechanistic insight into Mn(i) catalysed transfer hydrogenation

2020 ◽  
Vol 10 (1) ◽  
pp. 169-179 ◽  
Author(s):  
Li Zhou ◽  
Datai Liu ◽  
Haiyi Lan ◽  
Xiujian Wang ◽  
Cunyuan Zhao ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Functional Groups ◽  
Driving Forces ◽  
Transfer Hydrogenation ◽  
Bifunctional Catalysts ◽  
Mechanistic Insight ◽  
Insight Into ◽  
Metal Ligand

The origin of different catalytic activity between two structurally similar Lewis basic bifunctional catalysts.

scholarly journals Molecular-dynamics simulations of urea nucleation from aqueous solution

2014 ◽  
Vol 112 (1) ◽  
pp. E6-E14 ◽  
Author(s):  
Matteo Salvalaglio ◽  
Claudio Perego ◽  
Federico Giberti ◽  
Marco Mazzotti ◽  
Michele Parrinello
Keyword(s):  
Aqueous Solution ◽  
Free Energy ◽  
Molecular Simulations ◽  
Finite Size ◽  
Nucleation Theory ◽  
Classical Nucleation Theory ◽  
Science And Engineering ◽  
Finite Size Effects ◽  
Dynamics Simulations ◽  
Insight Into

Despite its ubiquitous character and relevance in many branches of science and engineering, nucleation from solution remains elusive. In this framework, molecular simulations represent a powerful tool to provide insight into nucleation at the molecular scale. In this work, we combine theory and molecular simulations to describe urea nucleation from aqueous solution. Taking advantage of well-tempered metadynamics, we compute the free-energy change associated to the phase transition. We find that such a free-energy profile is characterized by significant finite-size effects that can, however, be accounted for. The description of the nucleation process emerging from our analysis differs from classical nucleation theory. Nucleation of crystal-like clusters is in fact preceded by large concentration fluctuations, indicating a predominant two-step process, whereby embryonic crystal nuclei emerge from dense, disordered urea clusters. Furthermore, in the early stages of nucleation, two different polymorphs are seen to compete.

scholarly journals Mechanistic Insight into Biopolymer Induced Iron Oxide Mineralization Through Quantification of Molecular Bonding

2019 ◽  
Author(s):  
K.K. Sand ◽  
Stanislav Jelavic ◽  
Sören Dobberschütz ◽  
P.D. Ashby ◽  
Matthew J. Marshall ◽  
...  
Keyword(s):  
Density Functional ◽  
Growth Dynamics ◽  
Complex Model ◽  
Nucleation Theory ◽  
Dynamic Force ◽  
Functional Theory ◽  
Thermogravimetric Data ◽  
Water Association ◽  
Molecular Bonding ◽  
Insight Into

Microbial production of iron (oxy)hydroxides on polysaccharide rich biopolymers occurs on such a vast scale that it impacts the global iron cycle and has been responsible for major biogeochemical events. Yet the physiochemical controls these biopolymers exert on iron (oxy)hydroxide formation are poorly understood. Here we used dynamic force spectroscopy to directly probe binding between complex, model and natural microbial polysaccharides and common iron (oxy)hydroxides. Applying nucleation theory to our results demonstrates that if there is a strong attractive interaction between biopolymers and iron (oxy)hydroxides, the biopolymers decrease the nucleation barriers, thus promoting mineral nucleation. These results are also supported by nucleation studies and density functional theory. Spectroscopic and thermogravimetric data provide insight into the subsequent growth dynamics and show that the degree and strength of water association with the polymers can explain the influence on iron (oxy)hydroxide transformation rates. <br>

Classical nucleation theory of homogeneous freezing of water: thermodynamic and kinetic parameters

2015 ◽  
Vol 17 (8) ◽  
pp. 5514-5537 ◽  
Author(s):  
Luisa Ickes ◽  
André Welti ◽  
Corinna Hoose ◽  
Ulrike Lohmann
Keyword(s):  
Kinetic Parameters ◽  
Thermodynamic Parameters ◽  
Nucleation Theory ◽  
Classical Nucleation Theory ◽  
Kinetic And Thermodynamic Parameters ◽  
Thermodynamic And Kinetic Parameters ◽  
Homogeneous Freezing

Different formulations of the kinetic and thermodynamic parameters of CNT are evaluated against measured nucleation rates.

Effect of Modification by WTP-08 on Dispersity of Nanosized CalciumCarbonate and Its Mechanism

2011 ◽  
Vol 688 ◽  
pp. 51-56
Author(s):  
Hao Ding ◽  
Bai Kun Wang ◽  
Ning Liang ◽  
Kun Liu
Keyword(s):  
Free Energy ◽  
Calcium Carbonate ◽  
Surface Energy ◽  
Chemical Method ◽  
Interfacial Free Energy ◽  
Free Energies ◽  
Polar Medium ◽  
Polar Media ◽  
Thermodynamic Effect ◽  
Interfacial Free Energies

The dispersity of nanosized calcium carbonate modified by alkyl amine dimethyl phosphonic acid (WTP-08) through mechano-chemical method in different media was investigated. The modification mechanism was investigated by analyzing the surface energy and its thermodynamic effect on dispersity of nanosized calcium carbonate. The results show that the free energies of nanosized calcium carbonate modified by WTP-08 and its interfacial free energies in air and non-polar media decrease significantly, while the interfacial free energy in water increases remarkably. It can be concluded that modification by WTP-08 improves the dispersion tendency of nanosized calcium carbonate in air and non-polar medium, while it decreases in water. Therefore, modification by WTP-08 makes the dispersity of nanosized calcium carbonate increase in air and non-polar medium and decrease in water.

scholarly journals Classical nucleation theory of immersion freezing: sensitivity of contact angle schemes to thermodynamic and kinetic parameters

2017 ◽  
Vol 17 (3) ◽  
pp. 1713-1739 ◽  
Author(s):  
Luisa Ickes ◽  
André Welti ◽  
Ulrike Lohmann
Keyword(s):  
Experimental Data ◽  
Contact Angle ◽  
Kinetic Parameters ◽  
Aerosol Particles ◽  
Nucleation Theory ◽  
Classical Nucleation Theory ◽  
Kinetic And Thermodynamic Parameters ◽  
Immersion Freezing ◽  
Thermodynamic And Kinetic Parameters ◽  
Homogeneous Freezing

Abstract. Heterogeneous ice formation by immersion freezing in mixed-phase clouds can be parameterized in general circulation models (GCMs) by classical nucleation theory (CNT). CNT parameterization schemes describe immersion freezing as a stochastic process, including the properties of insoluble aerosol particles in the droplets. There are different ways to parameterize the properties of aerosol particles (i.e., contact angle schemes), which are compiled and tested in this paper. The goal of this study is to find a parameterization scheme for GCMs to describe immersion freezing with the ability to shift and adjust the slope of the freezing curve compared to homogeneous freezing to match experimental data. We showed in a previous publication that the resulting freezing curves from CNT are very sensitive to unconstrained kinetic and thermodynamic parameters in the case of homogeneous freezing. Here we investigate how sensitive the outcome of a parameter estimation for contact angle schemes from experimental data is to unconstrained kinetic and thermodynamic parameters. We demonstrate that the parameters describing the contact angle schemes can mask the uncertainty in thermodynamic and kinetic parameters. Different CNT formulations are fitted to an extensive immersion freezing dataset consisting of size-selected measurements as a function of temperature and time for different mineral dust types, namely kaolinite, illite, montmorillonite, microcline (K-feldspar), and Arizona test dust. We investigated how accurate different CNT formulations (with estimated fit parameters for different contact angle schemes) reproduce the measured freezing data, especially the time and particle size dependence of the freezing process. The results are compared to a simplified deterministic freezing scheme. In this context, we evaluated which CNT-based parameterization scheme able to represent particle properties is the best choice to describe immersion freezing in a GCM.

scholarly journals Classical nucleation theory of immersion freezing: Sensitivity of contact angle schemes to thermodynamic and kinetic parameters

2016 ◽  
Author(s):  
L. Ickes ◽  
A. Welti ◽  
U. Lohmann
Keyword(s):  
Experimental Data ◽  
Contact Angle ◽  
Kinetic Parameters ◽  
Aerosol Particles ◽  
Nucleation Theory ◽  
Classical Nucleation Theory ◽  
Kinetic And Thermodynamic Parameters ◽  
Immersion Freezing ◽  
Thermodynamic And Kinetic Parameters ◽  
Homogeneous Freezing

Abstract. Heterogeneous ice formation by immersion freezing in mixed-phase clouds can be parameterized in general circulation models (GCMs) by Classical Nucleation Theory (CNT). CNT parameterization schemes describe freezing as a stochastic process including the properties of insoluble aerosol particles, so called ice nuclei, in the droplets. There are different ways how to describe the properties of aerosol particles (i.e. contact angle schemes), which are compiled and tested in this paper. The goal of this study is to find a parameterization scheme for GCMs to describe immersion freezing with the ability to shift and adjust the slope of the freezing curve compared to homogeneous freezing to match experimental data. The results of using CNT are very sensitive to unconstrained kinetic and thermodynamic parameters in the case of homogeneous freezing leading to uncertainties in calculated nucleation rates Jhom of several orders of magnitude. Here we investigate how sensitive the outcome of a parameter estimation for contact angle schemes from experimental data is to kinetic and thermodynamic parameters. We show that additional free parameter can mask the uncertainty of Jimm due to thermodynamic and kinetic parameters. Different CNT formulations are fitted to an extensive immersion freezing dataset as a function of particle diameter (d), temperature T and time t for different mineral dust types, namely kaolinite, illite, montmorillonite, microcline (K-feldspar) and Arizona test dust. It is investigated how accurate different CNT formulations (with the estimated fit parameters) reproduce the measured freezing curves, especially the time and particle size dependence of the freezing process. The results are compared to a simplified deterministic freezing scheme. It is evaluated in this context which CNT based parameterization scheme to represent particle properties is a good choice to describe immersion freezing in a GCM.

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