Synthesis of Polymer Nanoparticles via Vapor Phase Deposition onto Liquid Substrates

Abstract

In this article, the growth of polymer nanoparticles formed at the liquid-vapor interface via vapor phase polymerization is studied. The particles grow by polymer aggregation, which is driven by the surface tension interaction between the liquid and polymer. It is demonstrated that the mechanism of particle growth is determined by whether polymer particles remain at the liquid-vapor interface or submerge into the liquid. The position of the particles depends on the interaction between the polymer and the liquid. For example, the deposition of poly(n-butyl acrylate) onto poly(dimethyl siloxane) and Krytox liquids leads to the formation of nanoparticles that remain at the liquid-vapor interface. The size of these particles increases as a function of deposition time. The deposition of poly(4-vinylpyridine) onto poly(dimethyl siloxane) and Krytox leads to the formation of nanoparticles that submerge into the liquid. The size of these particles does not significantly change with deposition time. Our study offers a new rapid, one-step synthetic approach for fabricating functional polymer nanoparticles for applications in catalysis, photonics, and drug delivery.

Plasma Processing of Low Vapor Pressure Liquids to Generate Functional Surfaces

“…In contrast to metal films, the deposition of parylene resulted in transparent and stable yet extremely flexible films. Other polymer materials, such as poly(2-hydroxyethyl methacrylate) (PHEMA), were deposited via iCVD as films, encapsulations or nanoparticles on ionic liquids, silicone oils or liquid PDMS [ 37 , 38 , 39 , 40 , 41 , 42 ]. The mechanisms which are discussed to be responsible for film and particle formation at the liquid’s surface are similar to the processes described for the deposition of metals.…”

“…The mechanisms which are discussed to be responsible for film and particle formation at the liquid’s surface are similar to the processes described for the deposition of metals. The authors describe an initial nucleation and subsequent formation of bigger aggregates due to film-forming material randomly diffusing across the liquid’s surface [ 40 , 41 , 42 ]. Whether the precursor material arriving at the liquid substrate forms floating clusters or submerges into the liquid depends on the intermolecular forces predominating gravitational effects [ 27 , 41 , 42 , 43 ].…”

“…The authors describe an initial nucleation and subsequent formation of bigger aggregates due to film-forming material randomly diffusing across the liquid’s surface [ 40 , 41 , 42 ]. Whether the precursor material arriving at the liquid substrate forms floating clusters or submerges into the liquid depends on the intermolecular forces predominating gravitational effects [ 27 , 41 , 42 , 43 ]. In accordance with the deposition of metal films, the occurrence of internal film stress and resulting wrinkling has been described for plasma-enhanced chemical vapor deposition (PECVD) processes which have been applied using monomers, such as ethylene, methane, hexamethyldisiloxane (HMDSO), silane or a mixture of carbon tetrafluoride and argon, to deposit closed films on liquids [ 27 , 43 ].…”

Microstructured Films Formed on Liquid Substrates via Initiated Chemical Vapor Deposition of Cross-Linked Polymers

“…34−40 The deposition of linear polymers leads to the formation of either dense polymer films or discrete polymer particles depending on the polymerliquid surface tension interactions. 41,42 In this paper, we demonstrate that we can synthesize unique microstructured films by depositing cross-linked polymers at liquid surfaces under standard iCVD processing conditions. The chemical cross-links result in the formation of films containing micron-sized coral-like features.…”

Strategies for Drug Encapsulation and Controlled Delivery Based on Vapor‐Phase Deposited Thin Films

“…As afore‐mentioned, such an encapsulating shell often acts then as diffusion membrane in order to have a timed release and/or as protective barrier, which allows the drug release to occur when specific conditions are met (e.g., barrier disintegration at a specific site in the body). Several vapor phase techniques have been employed for the direct encapsulation of drugs or drug loaded media, taking into account the possibility to treat a vast variety of substrates, such as solid surfaces, nanostructured/engineered surfaces, particles, but also on delicate substrates like amorphous drug films or liquid thin films …”