Budhlall Polymer Colloids & Soft Matter Group: Research Projects

Research Theme: Smart Stimuli-Responsive Polymers

Core-shell Microcapsules for Targeted, Controlled Delivery and Release

A major focus of our group's research is to create polymer colloids that can respond to stimuli by altering their properties or performing a desired task. We can do this through liquid-liquid interface driven assembly of colloidal building blocks and utilizing various heterogeneous polymerization strategies to fabricate a variety of microcapsules featuring multicore-crosslinked shell of poly(N-isopropylacryamide)(PNIPAm) particles. In this study, a multicore-shell structure was achieved through an oil/water/oil double emulsion method. We are interested in studying how these particles can be used for applications in encapsulation and delivery.

 

Layer-by-layer Polymer-Liposome Nanocapsules

Nanoengineered polymer capsules assembled via a layer-by-layer (LbL) deposition of polymers onto colloidal particles are promising candidates for their use as carriers in therapeutic delivery of anticancer drugs and protein and peptide vaccines. We have developed strategies to prepare temperature sensitive polymer-liposome capsules with enhanced temperature response, improved long-term stability and controlled release of anticancer drugs for chemotherapy. This project is in collaboration with Dr. Marta Ruano-Aldea of the Complutense University of Madrid, Spain.

 

Janus Colloids with Bulk and Surface Anisotropy

A versatile new concept was developed for the synthesis of Janus colloids composed of Laponite nanoclay armored poly(styrene) colloids with an anisotropic surface potential via a double Pickering emulsion template. First, polystyrene or poly(divinylbenzene) colloids stabilized with Laponite nanoclay are synthesized via a Pickering miniemulsion approach. These nanoparticle-stabilized colloids were then templated at a wax-water interface in a second Pickering emulsion in order to chemically modify one hemisphere of the colloids. Janus modification of the colloids was accomplished by cation exchange of sodium ions, originally present on the surface of the Laponite with various salts of modifying ions (Ca(2+), Fe(2+), and Fe(3+)) in the suspension.

 

Biodegradable Shape Memory Polymers

The focus of this work is to synthesize semicrystalline poly(e-caprolactone) (PCL) copolymer networks with stimuli-responsive shape memory behavior.  We are currently investigating a series of triblock copolymers with tunable shape memory transition temperatures, ranging from 54 C to close to body temperature. Our work establishes a general design concept for inducing a shape memory effect into any semicrystalline polyester network. More specifically, it can be applied to systems which have the highest transition temperature closest to the application temperature. An advantage of our novel copolymers is their ability to be cross-linked with UV radiation without any initiator or chemical cross-linker. Possible applications are envisioned in the area of endovascular treatment of ischemic stroke and cerebrovascular aneurysms, and for femoral stents.

 

Self-Healing Anticorrosion Coatings

The main goal of this research is to synthesize, characterize and formulate, fully renewable polyesters that are designed to be suitable for self-healing coating applications. Nanocontainers with encapsulated low-molecular-weight inhibitors allows for the immediate or prolonged release of the encapsulated active material triggered by specific changes in the environment surrounding the container or directly in the container shell.

 

Arterial Prototype Model for Biodegradation Studies of Polymers

There are currently no tests to determine degradation rates and characteristics of bioabsorbable materials that come in direct contact with blood. Blood follows a helical flow pattern and is momentum driven rather than pressure driven resulting in conditions not simulated in degradation tests. This is of concern to the degradation of stents because certain stent designs have the potential to liberate fragments large enough to induce strokes or other detrimental health concerns. A prototype designed to simulate in-vivo conditions including flow rates, pressures, temperatures, and flow characteristics was designed and built. This system was designed with a fast change testing chamber to allow sample removal and different configurations to simulate different sized arteries and conditions. The critical consideration for the testing chamber was the silicone artificial artery to simulate helical flow found in blood vessels. The effects of this flow pattern was compared to laminar and turbulent flow patterns and determined to best simulate actual body conditions. Degradation of polymers was characterized with weight loss of the sample, visual inspection via camera, and observations of liberated pieces running through meshes to indicate size.

 

Research Theme: Sustainability

Green Synthesis of Biosurfactants

The goal of our research is to develop a new class of safer surfactants as a sustainable alternative to toxic Nonylphenol ethoxylates (NPEs). Although effective as cleaning agents, NPEs are bio-accumulative and degrade into more toxic and less biodegradable compounds that are known to be endocrine disruptors, threatening both aquatic and human life. While there are several partly bio-based alternatives for NPEs available commercially, their efficacy and bio-degradability are not well established. Therefore, there is an immediate need for non-toxic, bio-based alternatives (from renewable resources) that can be as effective as NPEs. This project is in collaboration with Dr. Ramaswamy Nagarajan at UML.

 

Research Theme: Self and Directed Assembly

Monodispersed SWCNT for Chemical Sensors

In this project we apply the fundamental paradigm of materials science and engineering (structure-property-processing-performance) to hybrid hard (SWCNT) and soft materials (surfactants) at the nanometer length scale. This highly interdisciplinary project is enabled by a sophisticated suite of instrumentation including ultra-high vacuum (UHV) scanning tunneling microscopy (STM), and other equipment for studying the electrical and optical properties of materials. Ongoing research projects range from fundamental studies (e.g., zeta potential of monodispersed SWCNTs) to applied technology development (e.g., optimization of nanotubes for chemical sensor devices). This project is in collaboration with Prof. Carol Barry at UML.



DNA Directed Assembly of Janus Nanoparticles

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The goal of this project is to develop a process that will enable high-rate / high-volume “bottom-up”, precise, directed assembly of “Janus” particles with anisotropic functionality using DNA hybridization. Specifically, we will use the complementarily of DNA strands attached to different size latex particles to specifically control colloidal aggregation, in order to create templates for preparation of colloidal arrays of novel electro-optical properties. This project is in collaboration with Dr. Valeria Milam of Georgia Institute of Technology.