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Inorganic Protection of Polymer Nanocapsules: A Strategy to Improve the Efficiency of Encapsulated Optically Active Molecules
Author(s) -
Katta Kartheek,
Busko Dmitry,
Landfester Katharina,
Baluschev Stanislav,
MuñozEspí Rafael
Publication year - 2018
Publication title -
israel journal of chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.908
H-Index - 54
eISSN - 1869-5868
pISSN - 0021-2148
DOI - 10.1002/ijch.201800111
Subject(s) - nanocapsules , chemistry , miniemulsion , polymer , chemical engineering , perylene , polystyrene , polymerization , photochemistry , polymer chemistry , molecule , nanoparticle , organic chemistry , engineering
We demonstrate that the efficiency under ambient conditions of optically active molecules encapsulated in polymer nanocapsules can be significantly improved by depositing an inorganic layer onto the polymeric shell. A triplet‐triplet annihilation upconversion (TTA‐UC) system consisting of a porphyrin derivative and perylene is used as a representative case. Different inorganic materials are deposited on the surface of functionalized polymer nanocapsules synthesized by free‐radical polymerization in miniemulsion. First, a silicate clay with formula [Si 8 (Mg 5.45 Li 0.4 )O 20 (OH) 4 ]Na 0.7 is deposited on the surface of positively charged polystyrene nanocapsules via layer‐by‐layer deposition. Second, controlled in situ mineralization of hydroxyapatite and cerium(IV) oxide are carried out on the surface of negatively charged polystyrene nanocapsules. In both cases the inorganic materials on the nanocapsule surface act as a scavenger and avoid the entry of oxygen from the external environment. By avoiding the entry of oxygen, the photo‐oxidation process of perylene molecules is avoided within the system, and an increase in the TTA‐UC properties occurs.