Crystallization in Microemulsions: A Generic Route to Thermodynamic Control and the Estimation of Critical Nucleus Size

Cooper, Sharon J.; Cook, Oliver; Loines, Natasha

doi:10.5772/47977

Cited by 3 publications

(4 citation statements)

References 42 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Importantly, this particle growth rate is significantly reduced compared to that of bulk solution where the reactants are spatially unrestricted, and it is this that enables the formation of nanographitic aggregates rather than humins. The formation of nanographite via this novel microemulsion route is similar to a thermodynamic control of crystallization methodology. , …”

Section: Resultsmentioning

confidence: 98%

“…The formation of nanographite via this novel microemulsion route is similar to a thermodynamic control of crystallization methodology. 24,25 A reversible reaction pathway is a prerequisite for thermodynamic control. This reversibility ensures that less stable but quicker growing nuclei readily dissolve, thus enabling an equilibrium population of nuclei dominated by the most stable form to be achieved.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Nanographite Synthesized from Acidified Sucrose Microemulsions under Ambient Conditions

Hargreaves

Cooper

2016

Crystal Growth & Design

View full text Add to dashboard Cite

We show here that nanographite can be synthesized at room temperature and pressure through a simple process of acidifying sucrose microemulsions. This is in contrast to conventional wisdom, which stipulates that graphite can only be produced using high temperatures. Natural graphite arises via progressive metamorphisms of carbonaceous material subjected to temperatures above ∼600 K and pressures >2 kbar. Synthetic pyrolytic graphite requires temperatures >2500 K, and even nanographite formation from amorphous carbons requires temperatures >850 K. Our synthesis route utilizes the dehydration of sucrose by concentrated sulfuric acid, a variant of the well-known carbon black snake experiment, which produces an amorphous carbonaceous product. Crucially, though, we conduct the reaction in nanometer-sized microemulsion droplets to exert control over the reaction and sheet stacking process. This ensures that only sufficiently pristine graphene nanosheets can stack, thereby producing nanographite in a simple one-step synthesis under ambient conditions. The primary nanographitic particles of size ∼3–30 nm stack in crystallographic registry to form larger 250 nm- to μm-sized nanographitic aggregates. The amount of nanographite produced from the microemulsions is limited, however, because the sucrose concentration must be kept very low to slow the reaction kinetics. Hence, this is not a viable method for commercially producing nanographite.

show abstract

Section: Resultsmentioning

confidence: 98%

Section: ■ Results and Discussionmentioning

confidence: 99%

Nanographite Synthesized from Acidified Sucrose Microemulsions under Ambient Conditions

Hargreaves

Cooper

2016

Crystal Growth & Design

View full text Add to dashboard Cite

show abstract

“…For example, Tester et al 32 looked at calcium carbonate crystallisation in vesicles, around 100 nm across. Cooper and coworkers 33,34 have studied crystallisation (of glycine and other molecules, and of graphene) in microemulsions, where nucleation is believed to occur in microemulsion droplets of order 10 nm across. Ward and coworkers, and others, have studied crystallisation in nanoscale pores, 35 including, for example, glycine in nanoscale diameter cylindrical pores.…”

Section: Resultsmentioning

confidence: 99%

Estimation of the Scaling of the Nucleation Time with Volume When the Nucleation Rate Does Not Exist

Sear

2013

Crystal Growth & Design

View full text Add to dashboard Cite

Recent experimental [Diao et al., J. Am. Chem. Soc. 2011 133, 3756.] and simulation results [Sear, J. Phys. Cond. Matt. 2012 24, 052205.] are not consistent with a nucleation rate that is in the thermodynamic limit. This has consequences, if the rate is not in the thermodynamic limit, the time for nucleation will not necessarily scale as one over system size.Here, I show how to analyse data for nucleation times to test for the existence of a well defined nucleation rate. I also show how to estimate the scaling of the nucleation time with the number of nucleation sites. The prediction is that the farther the system is from the thermodynamic limit, the more rapidly the nucleation time varies with system size. To make this prediction, I use extreme-value statistics. I also show how nucleation data can be analysed to extract information on the heterogeneity in the surfaces nucleation is occurring on.

show abstract

“…It can be seen that the nucleation rate I remains negligibly small until the supersaturation or supercooling reaches a critical value, the Ostwald metastable limit, at which point I suddenly and dramatically increases. Hence, the onset crystallization temperature, Tc, can be identified with this metastable limit, and the corresponding nucleation rate can be set, with little loss in accuracy, to a suitable detection limit for the technique monitoring the crystallization [46]. In many experiments, the critical supersaturation is defined as the supersatuation that leads to a nucleation rate J equal to 1 nucleus cm -3 s -1 [47,48].…”

Section: Homogeneous Nucleationmentioning

confidence: 99%

Sol-gel derived icephobic coatings for large outdoor structures

Fu¹

View full text Add to dashboard Cite

Ice accretion possesses serious challenges for maintaining the operation and performance of large outdoor structures in cold climate. Icephobic materials have attracted much attention recently because they have demonstrated good promise in mitigating the problems. Superhydrophobic materials provide a viable option for the development of icephobic materials, as they have several advantages including slower heat transfer and lower sliding angle, which could potentially be exploited for decreasing the icing temperature, increasing the icing lag time, and reducing the ice adhesion strength, etc. However, based on the literatures, not all superhydrophobic materials show icephobic properties. The effect of surface energy, roughness, morphology and condensation should be carefully considered. In this report, investigation of ice nucleation behaviour and ice adhesion has been presented. The commonly adopted anti-icing tests and materials system for anti-icing applications were summarized based on existing literatures. In order to investigate the effect of surface properties on icephobicity, several series of samples were prepared by mechanical grinding and spraying sol-gel coating. The surface energy, roughness, wettability at different temperatures, ice adhesion and icing temperatures were measured. It was found out that the intrinsic surface energy and surface morphology of the coatings play important roles together in terms of anti-icing performance. Not all superhydrophobic surfaces, as indicated by the water contact angle at room temperatures, could remain water repellent with reduced ice adhesion at low temperatures. The anti-icing performance are closely correlated with the surface properties at lower temperatures instead of that at room temperature. The two aspects of the anti-icing performance, i.e., ice adhesion and icing temperature, are not xvii

show abstract

Crystallization in Microemulsions: A Generic Route to Thermodynamic Control and the Estimation of Critical Nucleus Size

Cited by 3 publications

References 42 publications

Nanographite Synthesized from Acidified Sucrose Microemulsions under Ambient Conditions

Nanographite Synthesized from Acidified Sucrose Microemulsions under Ambient Conditions

Estimation of the Scaling of the Nucleation Time with Volume When the Nucleation Rate Does Not Exist

Sol-gel derived icephobic coatings for large outdoor structures

Contact Info

Product

Resources

About