Upper or lower critical solution temperature, or both? Studies on cationic copolymers of N-isopropylacrylamide

Single molecule tracking studies of lower critical solution temperature transition behavior in poly(N-isopropylacrylamide).

Spatial and temporal heterogeneities in expanded and collapsed surface bound poly(N-isopropylacrylamide), pNIPAAm, films are studied by single molecule tracking (SMT) experiments. Tracking data are analyzed using both radius of gyration (R(g)) evolution and confinement level calculations to elucidate the range of behaviors displayed by single Rhodamine6G (R6G) molecules. Confined diffusion that...

Humidity effects on the wetting characteristics of poly(N-isopropylacrylamide) during a lower critical solution transition.

Poly(N-isopropylacrylamide) (PNIPAM) is expected to find utility in tissue engineering and drug delivery, among other biomedical applications. These applications capitalize on the intrinsic lower critical solution temperature (LCST) of the polymer: below the LCST, enthalpic gain from intermolecular hydrogen bonding between PNIPAM and water molecules dominates the solvation; above the LCST, entr...

Prediction of lower critical solution temperature of N-isopropylacrylamide-acrylic acid copolymer by an artificial neural network model.

In this paper, we have investigated the lower critical solution temperature (LCST) of N-isopropylacrylamide-acrylic acid (NIPAAm-AAc) copolymer as a function of chain-transfer agent/initiator mole ratio, acrylic acid content of copolymer, concentration, pH and ionic strength of aqueous copolymer solution. Aqueous solutions with the desired properties were prepared from previously purified polym...

Obesity: problem, solution, or both?

Effects of upper or lower abdominal surgery on diaphragmatic function.

Changes in abdominal (delta AB) and rib cage (delta RC) movements, and in vital capacity, were compared between 23 patients undergoing upper or lower abdominal surgery at 1, 3 and 7 days after surgery. Diaphragmatic index was obtained by measuring the relative abdominal motion (delta AB/delta AB + delta RC) using magnetometers. Electrical activity of abdominal muscles was assessed using needle ...