Rheological properties of poly(ethylene glycol)/poly(N‐isopropylacrylamide‐co‐2‐acrylamido‐2‐methylpropanesulphonic acid) semi‐interpenetrating networks

Abstract

For the increasing demands of multifunctional materials in applications such as drug delivery system, a pH-and temperature-responsive polyelectrolyte copolymer gel system was studied using rheometry. Rheological properties, determined by plate-plate rheometry in oscillatory shear, of hydrogels formed by free radical initiated copolymerization of N-isopropylacrylamide (NIPA) and 2-acrylamido-2-methylpropanesulphonic acid (AMPS) in the presence of methylene bisacrylamide (MBAA) as crosslinker are compared with the properties of semi-interpenetrating network (SIPN) polyelectrolyte gels made by incorporation of poly(ethylene glycol) with molar mass 6000 g mol 21 (PEG6000). Based on our systematic studies for this PEG/SIPN system, the effects of initiator and crosslinker concentration, relative proportions of comonomer units in the main chains, PEG6000 content and temperature on viscoelastic properties, unusual high storage moduli at small strain for the SIPN were discussed. The SIPN gel with characteristics of PEG molecules as well as pH and temperature responsiveness from AMPS and NIPA units has potential application in drug delivery system design. Ice-like rheological behavior of the PEG/AMPS-NIPA SIPN gels at low temperature was first time reported and water remains homogeneous without phase separation in PEG/AMPS-NIPA SIPN hydrogels at low temperature may be considered as an ideal candidate for water storage material.

Regimes of microstructural evolution as observed from rheology and surface morphology of crosslinked poly(vinyl alcohol) and hyaluronic acid blends during gelation

“…The G ′ of pure PVA is high at 12,900 Pa. With the addition of HA, the G ′ is lower by an order of magnitude, and varies from 894 to 1940 Pa. For PVAHA 26, the G ′ was found to be very low, since the gel did not form till 20 min. As many of the drug delivery hydrogel systems have G ′ in the range from 500 to 2000 Pa, most of the PVAHA hydrogels investigated in this work can be used for drug delivery applications …”

“…WILEYONLINELIBRARY.COM/APP many of the drug delivery hydrogel systems have G 0 in the range from 500 to 2000 Pa, most of the PVAHA hydrogels investigated in this work can be used for drug delivery applications. [29][30][31][32][33] Swelling characteristics of the membranes were evaluated, as these characteristics provide an insight into stability of the membrane structure and diffusion of water. The degrees of swelling for different compositions are listed in Table II.…”

Encapsulation of diclofenac sodium with acidic copolymer hydrogels based on PEG/poly(N‐isopropylacrylamide‐co‐2‐acrylamido‐2‐methyl‐1‐propanesulfonic acid) semi‐interpenetrating network using in situ loading technique

“…[1][2][3][4][5][6] PEG/(AMPS-co-NIPA) SIPN hydrogels (PEG-SIPN) are acidic polymer matrices in association with copolymer composition. 3 AMPS-based hydrogels, as a low-friction hydrogel layer that is fixed on the surface of a medical device such as a catheter, becomes a lubrication layer and reduces the friction.…”

“…As a pH‐ and temperature‐responsive functional copolymer system, poly(ethylene glycol)/poly(2‐acrylamido‐2‐methyl‐1‐propane sulphonic acid‐ co ‐ N ‐isopropylacrylamide) semi‐interpenetrating network PEG/(AMPS‐ co ‐NIPA) SIPN copolymers have been systematically studied elsewhere 1–6. PEG/(AMPS‐ co ‐NIPA) SIPN hydrogels (PEG‐SIPN) are acidic polymer matrices in association with copolymer composition 3.…”