Table 3.

CaCO₃ micro- and nanoparticles synthesized by emulsion method.

No.	Size (nm)	Microemulsion Composition	Surfactants	Results	References
1	60	Bis(2ethylhexyl) phosphoric acid, sodium hydroxide (NaOH), NaNO3, Na2CO3, span 83, Ca(NO3)2	Span 83	CCNPs were synthesized in a pseudo-vesicular system by double emulsion method in which size, structure, and mineralizing phase within the vesicle can be controlled using the aqueous phase composition. It was found that with increase in pH of the aqueous phase the vaterite particles aggregate changed to calcite of micro-sized single-crystalline rhombs	Hirai et al. (1997)
2	10–60 /80–100	Lubrizol (polybutene–succinimide pentamine), cyclohexane, CaCl2, Na2CO3	Lubrizol (polybutene–succinimide Pentamine)	Amorphous CaCO3 was synthesized by miniemulsion by using surfactants. Higher surfactant concentration which increases the reactive functional groups could help in better CaCO3 binding efficiency and adsorption ability	Pai and Pillai (2008)
3	1000–5000	n-Dodecane oil, 1% w/v stearic acid, 0.01 M NaOH, CaCl2/MgCl2 solution	Stearic acid, DHBC	A core–shell particle with an outer wall of CaCO3 was synthesized using the microemulsion method. The method is useful in templating porosity into the mineral shells Such a system is used in extraction processes, such as overdosed drug uptake from the blood	Patel et al. (2004)
4	5–20	CaCl2, Na2CO3, span 80, tween 80, toluene, methanol (CH3OH)	Tween 80 Span-80	The CCNPs were synthesized using growth and collapse of microbubbles under the ultrasonic field influence in the solution The method shortens the reaction time and saves more than 80% of energy, and controls the morphology and size of the nanoparticles	Badnore and Pandit (2015)
5	5–25	P-octyl polyethylene glycol phenyl ether (OP), and n-amyl alcohol, cyclohexane, CaCl2, Na2CO3, NaOH, acetone, ethyl alcohol, HCl, DL-Aspartic acid (Asp)	P-octyl polyethylene glycol phenyl ether (OP), and n-amyl alcohol, Cyclohexane, DL-Asp	CaCO3 nanocrystals with various polymorphs and multi-morphologies were controlled in the DL-Asp/OP bicontinuous microemulsion by maintaining the pH. Nucleation and growth of CaCO3 nanocrystal in OP bicontinuous microemulsion were done. DL-Asp was an important factor inducing the vaterite stable phase	Shen et al. (2007)
6	Not reported	Span -60, Tween-80, non-ionic surfactant, benzene, CaCl2, potassium carbonate, polypropylene	Span -60, Tween-80, Non-ionic surfactant	The shape and crystal structure were affected by the mixing method in the emulsion phase where the vaterite was used as a nucleating agent for polypropylene and the composite’s tensile strength with vaterite was greater than other crystal forms	Lyu et al. (1999)
7	40/36/21	CaCl2, Na2CO3, span-80, tween-80, toluene (99%), CH3OH, Stearic acid,	Tween-80, Span-80	Different sizes of surface-modified CCNPs were synthesized using a reverse microemulsion method With the increase in the concentration of surfactants, the water–surfactant molar ratio reduces, resulting in the developed nanoparticles size reduction	Ghadami Jadval Ghadam and Idrees (2013)
8	< 100	APS, SDS and n-pentanol, triethoxyvinyl silane (TEVS), PMMA	SDS and n-pentanol	Nano-CaCO3/PMMA core–shell particles with nano-CaCO3 acting as a core and PMMA working as a shell were synthesized successfully with the help of an atomized microemulsion method. This method of synthesis leads to wider industrial usage of core–shell nanoparticles because of their thermal stability and better dispersion	Chatterjee and Mishra (2013)
9	1–3	AM, MBAM, PVA, CaO, FC4430 and potassium persulfate (K2S2O8, KPS)	FC4430 (Fluro surfactant), PVA	Porous CaCO3/PAM composites were formed using CO2 in the water emulsion templating method. It involves the production of inorganic/polymer composites hydrogels, which are porous, by combining the emulsion templating with a reaction	Bing et al. (2007)
10	562	CaCl2 and Na2CO3 solutions, SDS, DTAB (dodecyl trimethylammonium bromide), n-Hexane	n-Hexane, DTAB, SDS	Vaterite nanocrystals were obtained in the stable water–oil emulsion with a high amount of non-ionic surfactants. Any decrease in surfactant content results in the precipitation of vaterite and aragonite crystals of a bigger size	Szcześ (2009)
11	100	CaCl2.2H2O, Na2CO3, SDS; CH3–(CH2)11–O–SO3–Na + ; iso-octane, CH3OH and 10X phosphate-buffered saline (PBS)	SDS	Micron-sized vaterite CaCO3 capsules were synthesized by the double emulsion method. The sulfate group of surfactants SDS which is negatively charged plays an important role to stabilize the vaterite polymorph which is metastable. The calcite capsules were developed from vaterite capsules after calcination at 500 °C. After being immersed in a PBS solution for 5 days, these vaterite capsules begin to collapse, showing their biodegradability which can have promising applications in controlled release of drug	Wu et al. (2008)