Huda A. Jerrihuda@engr.psu.edu

Advisor: Darrell Velegolvelegol@engr.psu.edu

Fabrication of Stable,Anisotropic Microcapsules

Funding: National Science Foundation (CBET Grant #0651611)

hole

Particle Lithography Key to Anisotropic Assemblies

Snyder, C. et al (Velegol). Langmuir 2005, 21, 4813-4815

Dual-Functionalized Particles by Particle Lithography

Yake, A. et al (Velegol). Biomacromolecules 2007, 8,1958-1965

Plan A: Processing Dye-Loaded Capsules

Initial Plan: form, load, settle capsules and lithograph

pH pH Fuse120oC

CONTROL, NO FUSERd6G Loaded (PSS/PAH)6 Capsules

Many Challenges Processing Delicate Capsules

pH pH Fuse120oC

(PSS/PAH)9 loaded and fused capsules

CONTROL, NO FUSERd6G Loaded (PSS/PAH)6 Capsules

Problematic Results: Collapsed Capsules, Agglomerates, Dye unloading, Low Yields…

Plan B: Patched Capsules Formed Around Solid Cores

BREAKTHROUGH: Functionalize and fuse with core intact

Masking Substrate Masking Substrate Masking Substrate

Uniform Fine and Coarse Coatings Created

(a)(a)

5μm

(b)

5μm

(b)

60 nm FYG 190 nm FYG

4 gL aR

Microcapsules Swell and Shrink After Fusing Still pH responsive after heat treatment Patch and shell completely intact Survive pH range 1 - 12

5μm

(a) (b)

5μm

(a) (b)

pH 2.5 pH 5

10 % reduction in capsule diameter

Microcapsules Retain Dye after Loading

Incubate with Rd6G, a cationic low MW dye

Loading

Overlay

Dried and Collapsed Lithographed Capsules Rehydrate

Bare Capsules ControlLithographed Capsules

(f)(a) (b) (c)5 µm (f)(a) (b) (c)5 µm (d) (e) (f)(d) (e) (f)

Dried 20 min 35 min Dried 25 min 120 min

H2O H2O

Spherical Morphology Restored Still Collapsed and Adhered to Substrate