Correct Option
The correct option is 1 only
Explanation
Hydrogels are three-dimensional, cross-linked networks of hydrophilic polymers that possess the unique ability to absorb and retain significant quantities of water or biological fluids without dissolving. This swelling behavior is governed by the presence of hydrophilic functional groups such as amino, carboxyl, and hydroxyl groups within the polymer backbone.
- Statement 1 is Correct: Hydrogels are extensively utilized in the pharmaceutical and biomedical sectors for controlled drug delivery. Their porous structure allows for the loading of drugs, which are then released at a predetermined rate in response to specific physiological stimuli such as changes in pH, temperature, or enzyme concentration. This ensures a sustained therapeutic effect and reduces systemic toxicity.
- Statement 2 is Incorrect: Mobile air-conditioning systems typically utilize refrigerants (such as R-134a or HFO-1234yf) and mechanical compressors to facilitate heat exchange. Hydrogels do not possess the thermodynamic properties or phase-change characteristics required to function as primary cooling agents or components in standard mobile air-conditioning cycles.
- Statement 3 is Incorrect: Industrial lubricants are primarily composed of base oils (mineral or synthetic) and additives designed to reduce friction and wear between moving surfaces. While some specialized water-based gels exist, hydrogels-due to their high water content and structural vulnerability under high shear stress-are not standard materials for the preparation of industrial lubricants.
Key Takeaway: Hydrogels are defined by their high water-retention capacity and biocompatibility, making them critical in medical applications like controlled drug delivery, while they lack the chemical and physical properties required for mechanical cooling or industrial lubrication.