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FROM:
Dayu Liu (1), Xinxing Peng (1,2), Binghui Wu (1,2), Xueyun Zheng (1), Tracy T. Chuong (1), Jialuo Li (1), Shigang Sun (2) and Galen D. Stucky (1)
(1) Department of Chemistry and Biochemistry, University of California, Santa Barbara, California 93106, United States
(2) State Key Laboratory for Physical Chemistry of Solid Surfaces, Collaborative Innovation Center of Chemistry for Energy Materials and Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
“Uniform concave polystyrene-carbon core-shell nanospheres by a swelling induced buckling process”, Journal of the American Chemical Society, Vol. 137, No. 31, pp 9772-9775, 2015, DOI: 10.1021/jacs.5b05027
ABSTRACT: We have developed a facile procedure that can create asymmetrical building blocks by uniformly deforming nanospheres into C∞v symmetry at low cost and high quality. Concave polystyrene@carbon (PS@C) core–shell nanospheres were produced by a very simple microwave-assisted alcohol thermal treatment of spherical PS@C nanoparticles. The dimensions and ratio of the concave part can be precisely controlled by temperature and solvents. The concavity is created by varying the alcohol-thermal treatment to tune the swelling properties that lead to the mechanical deformation of the PS@C core–shell structure. The driving force is attributed to the significant volume increase that occurs upon polystyrene core swelling with the incorporation of solvent. We propose a mechanism adapted from published models for the depression of soft capsules. An extrapolation from this model predicts that the rigid shell is used to generate a cavity in the unbuckled shell, which is experimentally confirmed. This swelling and deformation route is flexible and should be applicable to other polymeric nanoparticles to produce asymmetrical nanoparticles.
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