PMID- 33404247
OWN - NLM
STAT- PubMed-not-MEDLINE
LR  - 20210422
IS  - 1520-5827 (Electronic)
IS  - 0743-7463 (Print)
IS  - 0743-7463 (Linking)
VI  - 37
IP  - 2
DP  - 2021 Jan 19
TI  - Formation Mechanism of Multipurpose Silica Nanocapsules.
PG  - 918-927
LID - 10.1021/acs.langmuir.0c03286 [doi]
AB  - Core-shell structures containing active materials can be fabricated using almost 
      infinite reactant combinations. A mechanism to describe their formation is 
      therefore useful. In this work, nanoscale all-silica shell capsules with an 
      aqueous core were fabricated by the HCl-catalyzed condensation of tetraethyl 
      orthosilicate (TEOS), using Pickering emulsion templates. Pickering emulsions 
      were fabricated using modified commercial silica (LUDOX TMA) nanoparticles as 
      stabilizers. By following the reaction over a 24 h period, a general mechanism 
      for their formation is suggested. The interfacial activity of the Pickering 
      emulsifiers heavily influenced the final capsule products. Fully stable Pickering 
      emulsion templates with interfacially active particles allowed a highly stable 
      sub-micrometer (500-600 nm) core-shell structure to form. Unstable Pickering 
      emulsions, i.e., where interfacially inactive silica nanoparticles do not adsorb 
      effectively to the interface and produce only partially stable emulsion droplets, 
      resulted in capsule diameter increasing markedly (1+ mum). Scanning electron 
      microscope (SEM) and transmission electron microscope (TEM) measurements revealed 
      the layered silica "colloidosome" structure: a thin yet robust inner silica shell 
      with modified silica nanoparticles anchored to the outer interface. Varying the 
      composition of emulsion phases also affected the size of capsule products, 
      allowing size tuning of the capsules. Silica capsules are promising protective 
      nanocarriers for hydrophilic active materials in applications such as heat 
      storage, sensors, and drug delivery.
FAU - Graham, Michael
AU  - Graham M
AUID- ORCID: 0000-0001-6678-2496
AD  - Stephenson Institute for Renewable Energy, University of Liverpool, Peach Street, 
      Liverpool L69 7ZF, U.K.
FAU - Shchukin, Dmitry
AU  - Shchukin D
AD  - Stephenson Institute for Renewable Energy, University of Liverpool, Peach Street, 
      Liverpool L69 7ZF, U.K.
LA  - eng
PT  - Journal Article
DEP - 20210106
PL  - United States
TA  - Langmuir
JT  - Langmuir : the ACS journal of surfaces and colloids
JID - 9882736
SB  - IM
PMC - PMC8057668
COIS- The authors declare no competing financial interest.
EDAT- 2021/01/07 06:00
MHDA- 2021/01/07 06:01
PMCR- 2021/04/20
CRDT- 2021/01/06 12:14
PHST- 2021/01/07 06:00 [pubmed]
PHST- 2021/01/07 06:01 [medline]
PHST- 2021/01/06 12:14 [entrez]
PHST- 2021/04/20 00:00 [pmc-release]
AID - 10.1021/acs.langmuir.0c03286 [doi]
PST - ppublish
SO  - Langmuir. 2021 Jan 19;37(2):918-927. doi: 10.1021/acs.langmuir.0c03286. Epub 2021 
      Jan 6.