Internal damage in fiber-reinforced composites, materials used in structures of modern airplanes and automobiles, is difficult to detect and nearly impossible to repair by conventional methods. A small, internal crack can quickly develop into irreversible damage from delamination, a process in which the layers separate. This remains one of the most significant factors limiting more widespread use of composite materials.
However, fiber-composite materials can now heal autonomously through a new self-healing system, developed by researchers in the Beckman Institute's Autonomous Materials Systems (AMS) Group at the University of Illinois at Urbana-Champaign, led by professors Nancy Sottos, Scott White, and Jeff Moore.
Sottos, White, Moore, and their team created 3D vascular networks—patterns of microchannels filled with healing chemistries—that thread through a fiber-reinforced composite. When damage occurs, the networks within the material break apart and allow the healing chemistries to mix and polymerize, autonomously healing the material, over multiple cycles. These results were detailed in a paper titled "Continuous self-healing life cycle in vascularized structural composites," published in Advanced Materials.
"This is the first demonstration of repeated healing in a fiber-reinforced composite system," said Scott White, aerospace engineering professor and co-corresponding author. "Self-healing has been done before in polymers with different techniques and networks, but they couldn't be translated to fiber-reinforced composites. The missing link was the development of the vascularization technique."
"The beauty of this self-healing approach is, we don't have to probe the structure and say, this is where the damage occurred and then repair it ourselves," said Jason Patrick, a Ph.D. candidate in civil engineering and lead author.
The alien world of aquatic micro-organisms just got new residents: synthetic self-propelled swimming bio-bots.
A team of engineers has developed a class of tiny bio-hybrid machines that swim like sperm, the first synthetic structures that can traverse the viscous fluids of biological environments on their own. Led by Taher Saif, the University of Illinois Gutgsell Professor of mechanical science and engineering, the team published its work in the journal Nature Communications.
"Micro-organisms have a whole world that we only glimpse through the microscope," Saif said. "This is the first time that an engineered system has reached this underworld."
The bio-bots are modeled after single-celled creatures with long tails called flagella – for example, sperm. The researchers begin by creating the body of the bio-bot from a flexible polymer. Then they culture heart cells near the junction of the head and the tail. The cells self-align and synchronize to beat together, sending a wave down the tail that propels the bio-bot forward.
This self-organization is a remarkable emergent phenomenon, Saif said, and how the cells communicate with each other on the flexible polymer tail is yet to be fully understood. But the cells must beat together, in the right direction, for the tail to move.
"It's the minimal amount of engineering – just a head and a wire," Saif said. "Then the cells come in, interact with the structure, and make it functional."
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UNIVERSITY OF ILLINOIS AT URBANA CHAMPAIGN
Department of Atmospheric Sciences
School of Earth, Society, and Environment
—Tenure Track Assistant or Tenure Track/Tenured Associate Professor Search—
The Department of Atmospheric Sciences within the School of Earth, Society, and Environment at the University of Illinois at Urbana-Champaign invites applications for a full-time, tenure-track/tenured faculty position at the rank of Assistant or Associate Professor in climate science. The position is a nine-month academic appointment with a target start date of August 16, 2012.
The area of research, within the context of climate science, is open. Possible areas of emphasis include, but are not limited to, causes of past and future climate change; studies of climate and climate change at regional to global scales using numerical modeling, data analysis, and/or remote sensing techniques; climate change impacts and the mitigation of, and adaptation to future impacts of a changing climate. Candidates with exceptional strengths in other related research areas are also welcome to apply.
The successful candidate must have a Ph.D. degree by the date of appointment. The candidate must show the potential to establish a quality research and teaching program and collaborate effectively with other faculty. For consideration at the Associate level, the candidate must also demonstrate a strong external funding and publication record. A tenured Associate Professor appointment is possible for a candidate with the appropriate research credentials who has demonstrated excellence in teaching at either or both the graduate and undergraduate levels, commensurate with tenure guidelines at the University of Illinois at Urbana-Champaign.
The Department currently comprises 10 faculty, 5 emeritus faculty, 8 affiliated and adjunct faculty, 1 lecturer, 1 instructor, 9 research scientists, 51 graduate students, and 80 undergraduates. The members of the Department work in a broad range of research areas. Opportunities are available for collaborations with departments across the university, with linkages already existing with the Departments of Geography and Geology within the School of Earth, Society, and Environment, the Illinois State Water Survey, the National Center for Supercomputing Applications (NCSA), the Electrical and Civil Engineering Departments and many others. More information about the department can be found at www.atmos.illinois.edu, and about the School of Earth, Society and Environment at www.earth.illinois.edu.
A competitive salary, commensurate with qualifications and experience, and benefits package will be offered. To ensure full consideration applications must be submitted online by December 15, 2011. Create your U of I application through http://jobs.illinois.edu and upload your application materials: cover letter, vita, list of publications, record of research funding, teaching record, description of research and teaching interests, and names and email addresses of at least 3 references. Applicants may be interviewed before the closing date; however, no hiring decision will be made until after that date.
Questions can be addressed to Prof. Atul Jain, Chair of the Search Committee, at Email: jain1@illinois.edu or Phone: 217-333-2128.
The University of Illinois is an Affirmative Action /Equal Opportunity Employer and welcomes individuals with diverse backgrounds, experiences, and ideas who embrace and value diversity and inclusivity. (www.inclusiveillinois.illinois.edu)
