Colloids and Crystal Engineering Laboratory
Indian Institute of Technology Gandhinagar
Mechanical Behaviour of Organic Molecular Crystals
Solid-state materials composed of discrete organic molecules held together by weak non-covalent interactions, such as hydrogen bonding, π-π stacking, and van der Waals forces. Upon exposure to external mechanical, thermal, or optical stress, these crystals can exhibit mechanical behaviors, including reversible elastic bending, permanent plastic deformation, superelasticity, and photo-induced actuation. This dynamic compliance enables the use of organic crystals in applications such as flexible optoelectronics, soft robotics, optical waveguides, and pharmaceutical solid-state formulations. Our research efforts are focused on the crystal engineering of flexible molecular solids and understanding the effect of anisotropic molecular packing, intermolecular network motifs and crystal defects on the mechanical responsiveness, stability, and functional performance of organic molecular crystals.
Self-Healing Behaviour of Organic Molecular Crystals
Organic molecular crystals are dynamic solid-state materials composed of discrete organic molecules linked via non-covalent networks, including hydrogen bonds, halogen bonds, and van der Waals interactions. Upon mechanical damage, cleavage, or microcracking, these crystals can undergo autonomous or stimulus-triggered (such as thermal or optical) self-healing through directional molecular mobility and the spontaneous reformation of broken intermolecular bonds across fractured interfaces. Our research efforts are focused on the rational design of self-healing molecular solids and understanding the effect of crystal packing anisotropy, surface energy, molecular diffusion, and environmental conditions on the healing kinetics, structural restoration, and functional longevity of organic single crystals.
Engineering Microbubbles for Biomedical Applications
Microbubbles are colloidal particles with 0.1 to 10 μm diameter and consist of a shell made of lipid or protein molecules. The shell encapsulates a gaseous core containing gases such as Perfluorobutane (PFB), Sulphur Hexafluoride (SF6) or Oxygen (O2). The microbubble shell can contract and expand upon exposure to ultrasound. This phenomenon enables the use of microbubbles in applications such as contrast imaging, sonoporation and as drug/gene delivery vehicles. Our research efforts are focused on synthesis of microbubbles and understanding the effect of shell material, additives, storage medium and transport properties of core gas on the stability and biocompatibility of aqueous microbubble suspensions.
Engineering Microbubbles for Wastewater Treatment
Micro-nanobubbles (MNBs) are gas bubbles ranging from the micro- to nanoscale that are dispersed in water and exhibit relatively high stability, surface activity, and enhanced mass-transfer capabilities. In our work, MNBs are generated through surfactant-free hydrodynamic cavitation using fluid-mechanical principles and specialized pump systems. The formation and collapse of these bubbles can generate localized micro-jets and reactive oxygen species (ROS), which contribute to wastewater remediation through micro-flotation, enhanced oxygen transfer, and oxidation of contaminants. Our research focuses on understanding the hydrodynamic generation of MNBs and the factors that influence their behavior and treatment performance. In particular, we study how pump operating conditions, multiphase flow characteristics, and water chemistry affect bubble size, stability, ROS generation, and contaminant removal kinetics. The overall aim is to understand these interactions and optimize MNB-based treatment processes for efficient and sustainable wastewater remediation.
Drug Polymorphism Through Experiments and MD Simulations
Polymorphism is defined as the ability of a compound to exist in different solid crystalline phases, which have different arrangements and/or conformations of molecules in solid state. Studies related to the polymorphism are highly important for drug development as different polymorphs have different physicochemical properties and different solubilities. It is therefore neccessary to gain control over the formation of polymorphs during precipitation/crystallization and prevent polymorphic transformations during storage. We are trying to identify the thermodynamic and kinetic factors that significantly affect the polymorphism which can help in facilitating formation of desired polymorphs during crystallization.
Liquid and Gas Marbles
Liquid droplets encapsulated in a layer of hydrophobic particles are called as Liquid Marbles (LM). The hydrophobic shell provides a protective cover making the LM selectively permeable to gases and restrict contact of solid or liquid with the liquid inside the hydrophobic shell. LMs can be used as effective microreactors for biological/chemical processes and as gas sensors due to their selective permeability to gases. LMs can be synthesized by rolling or shaking of droplets on a hydrophobic powder bed, by mixing of liquid and particles in an optimal liquid to particle ratio or by releasing liquid droplets on a hydrophobic powder bed from a certain height. We are trying to understand the dynamics of LM formation during its impact on the bed of hydrophobic particles and estimate the effect of various process parameters such as viscosity, surface tension, and the nature of particles on LM formation.
