Stimuli-Sensitive Behaviour of Binary Graft Co-polymers (PP-g-DMAEMA)-g-NIPAAm and (PP-g-4VP)-g-NIPAAm in Acidic and Basic Medium

Abstract

The thermo-sensitive behaviour of the graft co-polymers (PP-g-DMAEMA)-g-NIPAAm and (PP-g-4VP)-gNIPAAm, synthesized using gamma rays, was studied under basic and acidic conditions. Dependence of pH on the LCST value was also studied by measuring the swelling percentage at different temperatures. Both graft co-polymers were shown to have LCST and UCST behaviours. UCST behaviour was found at acidic pH for both co-polymers. Behaviour towards UCST or LCST transition of graft co-polymers was dependent of NIPAAm content in acidic medium below their pK a . Response to pH was also studied at temperature above LCST.

Thermo‐ and pH‐ responsive copolymers: Poly(n‐Isopropylacrylamide‐co‐IAM) copolymers

“…Recently, it shows the potential in biomedical applications such as controlled drug release . The most representative temperature responsive polymer, poly(NIPAAm), has a lower critical solution temperature (LCST) of 32°C which is close to the body temperature. Since poly(NIPAAm) has both hydrophilic (amide) groups and hydrophobic (isopropyl) groups, hydrogen bonds between poly(NIPAAm) and water are strong to show hydrophilicity and a mixture of poly(NIPAAm) and water is a homogeneous solution as the temperature is below its LCST.…”

Novel pH- and Temperature-Sensitive Behavior of Binary Graft DMAEMA/PEGMEMA onto LDPE Membranes

“…The LCST of PDMAEMA is higher than 40 • C at pH 7.0. It is, therefore, impractical to utilize such a high LCST for biomedical applications [21][22][23]. pH differentiation very often exist in the human body; for example, between various segments of the gastrointestinal tract, between tumors and normal tissues, and between extracellular and endosomal/lysosomal microenvironments.…”

Preparation of stimuli‐responsive nanogels of poly [2‐(dimethylamino) ethyl methacrylate] by heterophase and microemulsion polymerization using gamma radiation

“…This is because of polymer–water interactions (swollen state) are broken and polymer–polymer interactions become stronger when temperature is increased (collapsed state) causing deswelling of nanogels. The temperature at which the particle switches between swollen and collapsed conformations is known as the LCST . LCSTs from Fig.…”

“…Poly [2‐(dimethylamino) ethyl methacrylate] (PDMAEMA) is a cationic polyelectrolyte that has shown to be both temperature and pH sensitive . It has a critical pH point around 7 which is close to the physiological pH .…”