© Copyright 2007 American Chemical Society
JANUARY 2, 2007 VOLUME 23, NUMBER 1
PREFACE
Stimuli-Responsive Materials: Polymers, Colloids, and Multicomponent Systems This special issue, Stimuli-Responsive Materials: Polymers, Colloids, and Multicomponent Systems, focuses on an area of intensive current study that has emerged from the application of bioinspired mechanisms to create functional systems using traditional materials. Two interconnected themes dominate this field: (1) the synthetic aspects and challenges related to the preparation of stimuli-responsive building blocks and (2) the physicochemical aspects connected to their processing. The articles in this issue of Langmuir provide a gauge of the importance of each theme. They center on diverse materials that have one common feature: they respond, in a controlled and reversible way, to an external stimulus, such as a mechanical deformation, light, electric or magnetic fields, or a change in temperature, pH, or ionic strength. The articles presented in this issue demonstrate that the field has evolved well beyond phenomenology and the demonstration of novel, intriguing, and perhaps interesting materials. The focus of these articles varies, including fundamental studies of the interactions driving the adaptation of materials to their changed environment, analytical methods to detect and quantify changes in material properties, and synthetic approaches that are successful in creating adaptative materials. The response of materials, such as polymer brushes or polyelectrolyte multilayers, often takes place at the air/water or solid/liquid interface, where favorable rearrangements can be created in environments with gradients of localized temperatures or concentrations. Nanoparticles, thick polymer films, or hydrogels also respond to environmental changes, and several articles in this issue demonstrate that the hierarchical organization of structural features across several length scales is one of the challenging aspects of the field. Scientists need to design spatial distributions that will facilitate simultaneous rearrangements of molecular arrays in space while maintaining their responsive character. A successful strategy, demonstrated in several articles, relies on the organization of multifunctional components in which stimuli-responsive objects, nanoparticles or nanotubes, are distributed in carefully designed microarrays. Applying an external or internal stimulus to such materials triggers the release of active agents serving functions as diverse as self-healing, controlled dosing of bioactive agents, or corrosion inhibitors. Most properties hinge on cooperative interactions, which depend on high- and low-density domain packing, together with interdomain manipulations. 10.1021/la0634490 CCC: $37.00 © 2007 American Chemical Society Published on Web 12/27/2006
2 Langmuir, Vol. 23, No. 1, 2007
This issue of Langmuir on stimuli-responsive materials is dedicated to current efforts in this field. The editors thank each author for his or her unique contribution and hope that taken together their work will initiate new endeavors and discussions among scientists working with continued inspiration and enthusiasm toward the design of the next generation of stimuliresponsive materials. Langmuir Senior Editor: Franc¸ oise M. Winnik Langmuir Editor-in-Chief: David G. Whitten Editorial Advisors: Marek W. Urban, University of Southern Mississippi; Gabriel Lopez, University of New Mexico, Albuquerque. LA0634490
Editorials
