To design versatile ordered nanomorphologies from the alternating sequence-controlled amphiphilic copolymers, in the current work, we have investigated the self-assembly behavior of a series of alternating copolymers, prepared through the reversible addition− fragmentation chain transfer (RAFT) polymerization of methoxy poly(ethylene glycol) (mPEG) functionalized styrene (VBP) and fatty acid attached maleimide (MF) monomers. The copolymers efficiently induced self-aggregation of the pendant side chains to afford both micelle and vesicle nanostructures in aqueous medium depending on the amphiphilicity of the side chains, as evident from dynamic light scattering (DLS) and transmission electron microscopy (TEM) analysis. The copolymers also induced thermoresponsive phase transition in water with lower critical solution temperatures (LCST) in the range of 69−88 °C depending on the mPEG side chain lengths, as determined from UV−vis spectroscopy. The hydrophobic dye and hydrophilic drug loading abilities of the synthesized copolymers were investigated using nile red and doxorubicin hydrochloride (DOX•HCl) as model compounds, respectively. The copolymers further formed reverse micelles in hexane owing to the presence of hydrophobic fatty acid pendants in the side chains, for which hexane is a good solvent. Additionally, the in vitro cytotoxicity study was performed for the synthesized alternating copolymers which revealed their nontoxic nature up to 500 μg/mL polymer concentration. Thus, the current work represents a fundamental strategy to construct biocompatible polymeric nanostructures from amphiphilic alternating copolymers, endowing noteworthy features for potential advantages.

A remarkable enhancement in crystalline melting temperature (Tm) was observed in a series of fatty acids and mPEG containing alternating copolymers with the lone increase in mPEG chain lengths.

A series of well-defined poly(D,L-lactide) and poly(ε-caprolactone) macromonomers (M n of ∼ 600 and ∼1200 Da) bearing a (meth)acrylate group at one side of the chain and either a hydrophobic nonpolar butyl group or a hydrophilic polar hydroxyl group at the other side of the chain were synthesized via 1,8-diazabicyclo[5.4.0]undec-7-ene-catalyzed ring-opening polymerization (ROP) of D,L-lactide and methanesulfonic acidcatalyzed ROP of ε-caprolactone, respectively. Then, a series of well-defined random copolymers (M n of ∼ 30 000 Da, Đ < 1.25) were prepared via reversible addition−fragmentation chain transfer (RAFT)-mediated copolymerization of N-isopropylacrylamide with these macromonomers. It was found that the cloud point temperature of the graft copolymers almost linearly decreased from 32.1 to ∼14 °C, with increasing the content of the polyester macromonomer with a hydrophobic butyl end group in a copolymer chain from 0 to 17 wt %. A much smaller shift in the transition temperature (from 32.1 to ∼ 23 °C) was observed for the graft copolymers of N-isopropylacrylamide with polyesters bearing a polar hydroxyl group at the chain end. The thermoresponsive behavior dependence on the copolymer composition of the synthesized graft copolymers or their binary mixtures with poly(N-isopropylacrylamide) (PNIPAM) was also demonstrated in this study. Finally, it was proved that the obtained graft copolymers showed no cytotoxicity, and films prepared from these copolymers displayed better cell adhesion as compared to those prepared from neat PNIPAM.

Application of poly-N-isopropylacrylamide (PNIPAM) and its more hydrophobic copolymers with N-tert-butylacrylamide (NtBA) as supports for cell sheets has been validated in numerous studies. The binary systems of these polymers with water are characterized by a lower critical solution temperature (LCST) in a physiologically favorable region. Upon lowering the temperature below the LCST, PNIPAM chains undergo a globule-to-coil transition, causing the film dissolution and cell sheet detachment. The character of the PNIPAM–water miscibility behavior is rather complex and not completely understood. Here, we applied atomic force microscopy to track the phase transition in thin films of linear thermoresponsive (co)­polymers (PNIPAM and PNIPAM-co-NtBA) prepared by spin-coating. We studied the films’ Young’s modulus, roughness, and thickness in air and in distilled water in a full thermal cycle. In dry films, in the absence of water, all the measured parameters remained invariant. The swollen films in water above the LCST were softer by 2–3 orders of magnitude and about 10 times rougher than the corresponding dry films. Upon lowering the temperature to the LCST, the films passed through the phase transition observed as a drastic drop of Young’s modulus (about an order of magnitude) and decrease in roughness in both polymers in a narrow temperature range. However, the films did not lose their integrity and demonstrated almost fully reversible changes in the mechanical properties and roughness. The thermal dependence of the films’ thickness confirmed that they dissolved only partially and required an external force to induce the complete destruction. The reversible thermal behavior which is generally not expected from non-cross-linked polymers is a key finding, especially with respect to their practical application in cell culture. Both the thermodynamic and kinetic factors, as well as the confinement effect, may be responsible for this peculiar film robustness, which requires overcooling and the aid of an external force to destroy the film.

A robust quantum dots-in-polymer composite based on a specially designed cross-linking polyisobutylene is developed. It possesses excellent photo- and chemical stability preserving the optical properties of Cu–Zn–In–S quantum dots.