摘要
Development of block copolymer(BCP)microparticles with switchable morphology in response to external stimuli is important for exploiting new intelligent materials.In this work,thermo/p H dual-responsive nanoparticles(NPs)were employed as a cosurfactant to modulate the self-assembly morphology of polystyrene-b-poly(2-vinylpyridine)(PS-b-P2VP)microparticles within confined emulsion droplets.The co-surfactant was synthesized by grafting poly(acrylic acid)-b-poly(N-isopropylacrylamide)onto the surface of Fe3O4NP.The introduction of the dual-responsive co-surfactant enabled thermo/p H dual-responsive reversible morphology transition of the PS-b-P2VP microparticles by tailoring the hydrophobicity and interfacial affinity of the cosurfactant.By using this strategy,the thermo-inert PS-b-P2VP self-assembled into pupa-like microparticles at T=10℃ and p H7.5,which could transform into tulip-like microparticles when T was increased to 50℃.When the p H value was increased to 11,the pupa-like particles turned into onion-like microparticles although the PS-b-P2VP was inert to alkali.However,the pupa-like microparticles remained unchanged when both T and p H were simultaneously increased.The PAA-b-PNIPAM-grafted Fe3O4NP surfactants showed obvious advantages over the linear PAA-b-PNIPAM surfactants in modulating the morphology transition,since the linear PAA-b-PNIPAM could not induce the reversible shape transition of microparticles.Our work provides an efficient strategy to achieve reversible shape transformation of BCP microparticles while the internal phase structure is preserved,which may be utilized to switch the structural color properties of BCP microparticles.
基金
supported by the National Natural Science Foundation of China (52222304,52293474,51933005,51903098)
the Open Research Fund of State Key Laboratory of Polymer Physics and Chemistry (2021–13)
Changchun Institute of Applied Chemistry,Chinese Academy of Sciences
the Analytical&Testing Center (HUST)and the Research Core Facilities of Life Science (HUST)for their support on TEM,H NMR,and FT-IR。
