**2.4 Transformation of soybean and sunflower oil to colloidosomes**

Colloidal particles are elementary to nature and technology. Self-assembly of colloids at liquid - liquid interface is well documented. Recently, there has been mounting concern in using this self-assembly system to form efficient superstructures, such as emulsions, microcapsules, particles and colloidal crystals. One of the most significant applications of this method is to formulate microcapsules known as colloidosomes, whose shells are composed of coagulated or fused colloid particles.

Based on this method, noval colloidosomes with coagulated or colloidal particles were produced in the presence of oil in water emulsion. Mineral medium with sunflower oil in the presence of marine *Bacillus* sp. and its hydrolytic enzyme and biosurfactants transform the oil into emulsion. Presence of Janus particle (amphiphilic compound nothing but the biosurfactant) stabilizes the emulsion and transform into stable colloidosomes. The presence of the particles at the water/oil interface minimizes the surface energy and therefore stabilizes the emulsion. The wettability and mobility of the particles will determine the stability of the emulsion and those factors are highly dependent on the hydrophobic/ hydrophilic character of the particles and transform into self-assembled supramolecular colloidosomes.

The largest yield of colloidosomes is obtained when using a surfactant to stabilize the oil/water interface. This introduces an electrostatic driving force to take the latex particle to the emulsion interface. The hydrophobicity of the latex particles is the driving force in the surfactant free case but it is evident that the particles are held a short distance apart, presumably due to an electrostatic repulsion in the plane of the emulsion. This repulsion is well known and is thought to operate through the organic phase. The following figure demonstrates the morphological features of colloidosomes obtained from soybean oil (A) and sunflower oil (B).

Transformation of Soybean Oil to Various Self-Assembled Supramolecular Structures 289

The obtained STLM was creamy-white in colour with soft nature, partially soluble in polar and non-polar solvents, however, completely soluble in ethylacetate and methanol. STLM showed layered, honeycombed, porous structure with channeled network in Scanning electron microscope. Different damages mode such as cracking, punching, cutting and delamination were made. Since minor damages like cracking healed at the very faster rate (24 hours) and however, healing of punching, cutting and delamination damages, took more than 96 hours and the healing rate differs with the depth of the damage. Figure 5 illustrates

However, STLM obtained in the present study, heal upon various damages (punching, delamination and cutting) without any inducers and also demonstrate more flexibility upon ageing (more than six months). Further, we found, surface rearrangement, diffusion and reunion of the self-healing material in the presence of aqueous atmosphere as evidenced through spread test conducted. The lower surface tension moieties at the end of the chain make the molecules migrate to the surface, and the diffusion and the interface results in the cross-linking and self-healing property. As reported by Wool (2008), healing of polymers proceeded with various stages of healing mechanisms, viz., surface rearrangement, wetting, diffusion and randomization and also suggest, the fibrillar morphology, nature of molecules

Further, wetting and spreading of the fluid on the surface of the material, enhances the healing process (Brochard, 1986). In the present study, while damaging the self-assembled tissue like material, the released imbibed materials (hydrophobic and hydrophilic) diffuse through cut ends and trigger the repairing and healing process. The attractive force between the molecules present inside the material and on the surface of the material assembles by itself due to the Van der Waals forces. Here, the driving forces were the hydrophobic components (free fatty acid and unhydrolyzed oil) present in multilayered channeled

With regard to wetting and dewetting processes of semi solid and liquid materials, in general, wetting makes the material to spread over the surface of the water, and in dewetting, the material shrinks and again wetting, spreading of a material transform the substrate to a very thin film (Scheludko, 1968 and lsraelachvili, 1985). However, in contradict to the said natural phenomena of wetting and dewetting, in the present study, we observed, a complete wetting (soaking), make STLM to shrink and the partial wetting, make it to spread. In the partial wetting state, (i) hydrostatic pressure makes the polymer to migrate towards the edge of the petriplate, which, (ii) further triggered by non-covalent bonding between the layers of the material and the hydrophobic components imbibed; (iii) the interface between the water and the material also acting as a driving force; (iv) Surface tension between the air and water interface also pull the material towards the edge. Presence of intramolecular bonding between the dimerized molecules gives the stability and

We herein report, transformation of soybean oil to macro-sized self-assembled organogel in the aqueous medium containing mineral salts, glucose and peptone. Experiments were carried out at 37C under agitation (200 rpm) for the period of 240 hours. Though different concentrations (0, 2.5, 5.0 and 10% (w/v)) of soybean oil was examined, the formation of macro-sized organogel was observed only with 10% concentration and the flasks receiving

the self-healing pattern of delamination damages of STLM.

at the end of the chain and *in situ* oxidation – reduction reactions.

structures.

it helps in the structure retrieval.

**2.6 Transformation of soybean oil to organogel** 

Fig. 4. Colloidosomes from (A) Soybean oil; (B) Sunflower oil.
