Supramolecular self-assembly and controllable drug release of thermosensitive hyperbranched multiarm copolymers

Delayed Crosslinking Amphiphilic Polymer Gel System with Adjustable Gelation Time Based on Competitive Inclusion Method

Delayed crosslinking polymer gel systems are widely utilized in deep profile control processes for water production control in oilfields. In this paper, a kind of delayed crosslinking amphiphilic polymer gel system with adjustable gelation time based on competitive inclusion was prepared and its delayed crosslinking gelling properties were studied. The amphiphilic polymer of P(acrylamide (AM)⁻sodium acrylate (NaA)⁻N-dodecylacrylamide (DDAM)) was synthesized and it showed much better salt resistance, temperature resistance, and shear resistance performance compared with hydrolyzed polyacrylamide (HPAM). Phenol can be controlled released from the the cavity of β-cyclodextrin (β-CD) ring in the presence of the hydrophobic group used as the competitive inclusion agent in the amphiphilic polymer backbone. Accordingly, the gelation time of the delayed crosslinking amphiphilic polymer gel system is closely related to release rate of the crosslinker from the the cavity of β-CD ring. This study screened an amphiphilic polymer with good salt resistance and temperature resistance performance, which can be used in high temperature and high salinity reservoirs, and provided a feasible way to control the gelation time of the polymer gel system by the competitive inclusion method.

The Synthesis of Backbone Thermo and pH Responsive Hyperbranched Poly(Bis(N,N-Propyl Acryl Amide))s by RAFT

Hyperbranched poly(methylene-bis-acrylamide), poly(bis(N,N-propyl acryl amide)) (HPNPAM) and poly(bis(N,N-butyl acryl amide)) were synthesized by reversible addition-fragmentation chain transfer polymerization. HPNPAMs showed lower critical solution temperature (LCST) due to an appropriate ratio between hydrophilic and hydrophobic groups. The effects of reaction conditions on polymerization were investigated in detail. The structure of HPNPAM was characterized by ¹H NMR, FT-IR, Muti detector-size exclusion chromatography (MDSEC) and Ultravioletvisble (UV-Vis). The α value reached 0.20 and DB was 90%, indicating HPNPAMs with compact topology structure were successfully prepared. LCSTs were tuned by M_w and the pH value of the solution. The change of molecular size was assayed by dynamic light scattering and scanning electron microscope. These results indicated that the stable uniform nanomicelles were destroyed and macromolecules aggregated together, forming large particles as temperature exceeded LCST. In addition, after the cells were incubated for 24 h, the cell viability reached 80%, which confirmed this new dual responsive HPNPAM had low cytotoxicity.

Self-assembled micelles based on branched poly(styrene-alt-maleic anhydride) as particulate emulsifiers

The self-assembled micelles of branched poly(styrene-alt-maleic anhydride) (BPSMA) are prepared and exhibit much superior emulsifying performance over the corresponding linear copolymer micelles as particulate emulsifiers.