PNVCL

PNVCL, or poly(N-vinylcaprolactam), is a synthetic, water-soluble polymer that exhibits thermo-responsive behavior in aqueous environments. The polymer shows a lower critical solution temperature (LCST), above which it desolvates and undergoes coil-to-globule transition. For the homopolymer, this LCST is typically near body temperature, around 30–34°C, but it can be tuned by molecular weight, copolymerization, and formulation conditions.

Chemically, PNVCL consists of N-vinylcaprolactam monomer units polymerized into long chains. The amide and lactam groups promote strong hydration at temperatures below the LCST. Below the LCST, PNVCL is hydrated and soluble; above the LCST, it becomes less soluble and can form gels or phase-separate, depending on concentration and crosslinking. The LCST is sensitive to additives, ionic strength, pH, and co-solvents, allowing customization for specific applications.

Synthesis of PNVCL is typically achieved via free radical polymerization of N-vinylcaprolactam using initiators such as AIBN, in organic solvents or emulsion systems. To form hydrogels, crosslinkers such as N,N′-methylenebisacrylamide are used. Control of molecular weight and polydispersity is important for consistent thermo-responsive behavior and mechanical properties.

Applications of PNVCL focus on temperature-triggered systems. They include drug delivery platforms that release payloads as temperature crosses the LCST, injectable or self-healing hydrogels, tissue engineering scaffolds, surface coatings, and microgels for sensing and responsive materials.

Advantages and considerations: PNVCL offers tunable LCST and generally favorable biocompatibility in studies, but biodegradability is limited and long-term safety requires careful evaluation. Purification to remove residual monomer and precise control of synthesis conditions are important for reproducibility and processing.