Amphiphilic self‐folding random copolymers exhibit different solution behaviors depending on the identity of the hydrophobic/hydrophilic units. Herein, it is demonstrated that changing the hydrophilic unit from poly(ethylene glycol) to the sugar trehalose causes increased discrepancy in the polarity difference with a fluorinated hydrophobic segment and changes the aggregation state of the polymer in water. The PEG‐fluorinated and trehalose/PEG‐fluorinated amphiphilic random copolymers were the most efficient at encapsulating a fluorinated agrochemical. The small‐molecule agrochemical exerts a strong influence on the self‐assembly of the polymers, demonstrating that fluorous interactions result in not only intramolecular self‐folding behavior but also intermolecular polymer association to form well‐defined nanoparticles. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem.
Carbohydrates are the fundamental building blocks of many natural polymers, their wide bioavailability, high chemical functionality, and stereochemical diversity make them attractive starting materials for the development of new synthetic polymers. In this work, one such carbohydrate,
- NSF-PAR ID:
- 10075711
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Journal of Polymer Science Part A: Polymer Chemistry
- Volume:
- 57
- Issue:
- 3
- ISSN:
- 0887-624X
- Page Range / eLocation ID:
- p. 432-440
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
More Like this
-
ABSTRACT 2019 ,57 , 352–359 -
ABSTRACT Herein, we present a facile and comprehensive synthetic methodology for the preparation of polyester‐polyamidoamine (PAMAM) (i.e., polyester: polylactide [PLA] (hydrophobic) and polyamidoamine, PAMAM [hydrophilic]) polymers. A library of PLA‐PAMAM linear dendritic block copolymers (LDBCs) in which both
l andd ,l polylactide were employed in mass ratios of 30:70, 50:50, 70:30, and 90:10 (PLA:PAMAM) were synthesized and analyzed. When placed in aqueous media, the immiscibility of the hydrophilic and hydrophobic segments leads to nanophase‐segregation exhibited as the formation of aggregates (e.g., vesicles, worms, and/or micelles). By employing both stereochemical configurations of PLA, the differentiation in mass ratios of PLA‐PAMAM aided in elucidating the structure–property relationships of the LDBC system and provided a means toward the control of nanoparticle morphology. Transmission electron microscopy and dynamic light scattering afford the size and shape of the nanoparticles with diameters ranging from 10.6 for low mass ratios to 122.4 nm for high mass ratios of PLA‐PAMAM and positive zeta‐potential values between +24.7 mV and +48.2 mV. Furthermore, small‐angle X‐ray scattering (SAXS) studies were employed to obtain more detailed information on the morphological assemblies constructed via direct dissolution. Such insights provide a pathway toward nanomaterials with unique morphologies and tunable properties deemed relevant in the development of next generation biomaterials. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019, 57, 1448–1459 -
ABSTRACT Polymers with multiple tunable responses were achieved by incorporating boronic acid functionality along the backbone of a thermoresponsive polymer. The inherent Lewis acidity and diol‐sensitivity of boronic acid moieties allowed these polymers to respond to changes in pH and glucose concentration. Through reversible addition‐fragmentation chain transfer copolymerization of boronic acid‐containing monomers with
N ‐isopropylacrylamide, well‐defined block copolymers were synthesized containing a hydrophilicN ,N ‐dimethylacrylamide block and a second, responsive block with temperature‐dependent water solubility, making the resulting polymers capable of self‐assembly into nanostructures upon heating. By incorporating boronic acids within the thermoresponsive block, the cloud point of the polymer depended on the solution conditions, including pH and diol concentration, allowing tunable cloud point ranges. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem.2017 ,55 , 2309–2317 -
ABSTRACT Block copolymers with donor and acceptor conjugated polymer blocks provide an approach to dictating the donor–accepter interfacial structure and understanding its relationship to charge separation and photovoltaic performance. We report the preparation of a series of donor‐linker‐acceptor block copolymers with poly(3‐hexylthiophene) (P3HT) donor blocks, poly((9,9‐dioctylfluorene)‐2,7‐diyl‐alt‐[4,7‐bis(thiophen‐5‐yl)‐2,1,3‐benzothiadiazole]‐2′,2″‐diyl) (PFTBT) acceptor blocks, and varying lengths of oligo‐ethylene glycol (OEG) chains as the linkers. Morphological analysis shows that the linkers increase polymer crystallinity while a combination of optical and photovoltaic measurements shows that the insertion of a flexible spacer reduces fluorescence quenching and photovoltaic efficiencies of solution processed photovoltaic devices. Density functional theory (DFT) simulations indicate that the linking groups reduce both charge separation and recombination rates, and block copolymers with flexible linkers will likely rotate to assume a nonplanar orientation, resulting in a significant loss of overlap at the donor–linker–acceptor interface. This work provides a systematic study of the role of linker length on the photovoltaic performance of donor–linker–acceptor block copolymers and indicates that linkers should be designed to control both the electronic properties and relative orientations of conjugated polymers at the interface. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys.
2018 ,56 , 1135–1143 -
ABSTRACT Neodymium‐based catalysts coordinated with phosphate ligands (NdCl3·3L), where L = triethyl phosphate (TEP) or tris(2‐ethylhexyl) phosphate (TEHP), were synthesized. The ring‐opening polymerizations (ROP) of ɛ‐caprolactone (ɛ‐CL) with these catalysts in the presence of benzyl alcohol initiator were performed, yielding polymers with well‐defined molecular weights and relatively narrow polydispersity index (PDI = 1.22–1.65).
In situ NMR analysis of the reaction between NdCl3·3TEP and benzyl alcohol indicated that ROP proceeds through a coordination‐insertion mechanism. The end groups of the resultant polymers were determined using MALDI‐ToF mass spectrometry and NMR spectroscopy. Thequasi‐living nature of this catalytic system was demonstrated by kinetic studies and the successful synthesis of the block copolymer poly(ɛ‐caprolactone)‐block ‐poly(l ‐lactide) by sequential monomer addition. Kinetic studies revealed that the catalyst with the bulkier TEHP ligand increased the rate of ROP of ɛ‐CL as compared to the TEP ligand. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem.2018 ,56 , 1289–1296