Polymerization-induced thermal self-assembly (PITSA)† †Electronic supplementary information (ESI) available: Experimental details, characterization data, and additional figures. See DOI: 10.1039/c4sc03334e Click here for additional data file.
نویسندگان
چکیده
Polymerization-induced self-assembly (PISA) is a versatile technique to achieve a wide range of polymeric nanoparticle morphologies. Most previous examples of self-assembled soft nanoparticle synthesis by PISA rely on a growing solvophobic polymer block that leads to changes in nanoparticle architecture during polymerization in a selective solvent. However, synthesis of block copolymers with a growing stimuliresponsive block to form various nanoparticle shapes has yet to be reported. This new concept using thermoresponsive polymers is termed polymerization-induced thermal self-assembly (PITSA). A reversible addition-fragmentation chain transfer (RAFT) polymerization of N-isopropylacrylamide from a hydrophilic chain transfer agent composed of N,N-dimethylacrylamide and acrylic acid was carried out in water above the known lower critical solution temperature (LCST) of poly(N-isopropylacrylamide) (PNIPAm). After reaching a certain chain length, the growing PNIPAm self-assembled, as induced by the LCST, into block copolymer aggregates within which dispersion polymerization continued. To characterize the nanoparticles at ambient temperatures without their dissolution, the particles were crosslinked immediately following polymerization at elevated temperatures via the reaction of the acid groups with a diamine in the presence of a carbodiimide. Size exclusion chromatography was used to evaluate the unimer molecular weight distributions and reaction kinetics. Dynamic light scattering and transmission electron microscopy provided insight into the size and morphologies of the nanoparticles. The resulting block copolymers formed polymeric nanoparticles with a range of morphologies (e.g., micelles, worms, and vesicles), which were a function of the PNIPAm block length.
منابع مشابه
Overcoming aggregation in indium salen catalysts for isoselective lactide polymerization† †Electronic supplementary information (ESI) available: Experimental section, full characterization of compounds in solution and in the solid state, polymerization and polymer analysis, details of reactivity, tacticity determination, DSC, PGSE studies, in situ polymerization studies. CCDC 1062730–1062733 and 1062738. For ESI and crystallographic data in CIF or other electronic format see DOI: 10.1039/c5sc01584g Click here for additional data file. Click here for additional data file.
متن کامل
Self-assembling α,γ-cyclic peptides that generate cavities with tunable properties† †Electronic supplementary information (ESI) available: Synthetic experimental details, DFT calculation details, additional figures (relevant NMR data) and schemes (synthetic schemes for peptide and amino acid preparation). CCDC 1400134. For ESI and crystallographic data in CIF or other electronic format see DOI: 10.1039/c5sc03187g Click here for additional data file. Click here for additional data file.
متن کامل
An unprecedented amplification of near-infrared emission in a Bodipy derived π-system by stress or gelation† †Electronic supplementary information (ESI) available: Experimental details, synthesis procedures and characterization data of the compounds, and additional figures. CCDC 1523313. For ESI and crystallographic data in CIF or other electronic format see DOI: 10.1039/c7sc01696d Click here for additional data file. Click here for additional data file.
متن کامل
Temporal switching of an amphiphilic self-assembly by a chemical fuel-driven conformational response† †Electronic supplementary information (ESI) available: Experimental section, synthetic procedures and supporting figures. See DOI: 10.1039/c7sc01730h Click here for additional data file.
متن کامل
Multiplexed DNA detection based on positional encoding/decoding with self-assembled DNA nanostructures† †Electronic supplementary information (ESI) available: Experimental details, additional DNA detection figures, and DNA sequence information. See DOI: 10.1039/c4sc02696a Click here for additional data file.
متن کامل