# Colloidal Assembly ## expand\_more #### Colloidal Co-Assembly Nanoporous architectures use periodic arrays of hollow spaces to generate the intense structural colors of butterflies, beetles, and birds, enhance the mechanical stability of bones, and facilitate gas exchange through egg shells. Analogous synthetic periodic nanoporous structures, known as inverse opals, offer a compelling materials strategy for use in optics as well as in fields ranging from catalysis and energy storage to tissue engineering. While inverse opals and other 3D photonic structures can be produced by top-down processes, a much simpler, lower cost approach to generating uniform pore size and order is to use self-assembling colloidal spheres to construct a patterned, periodic colloidal crystal, or opal, which then acts as a sacrificial template for self-assembling the porous structure. However, this technique has been plagued by uncontrolled crack and defect formation over the length scales required for most applications. We have discovered that taking a simpler approach - letting colloids and a silicate sol-gel precursor co-assemble in one step rather than sequentially – generates highly ordered, crack-free, multilayered inverse opal films on the scale of centimeters. We are currently investigating the mechanism behind this long-range order; co-assembly not only avoids the cracking and inhomogeneities associated with liquid infiltration into a preassembled opal but also appears to take advantage of an interplay between the assembling template and matrix that leads to correction of incipient defects. The versatility of this approach enables us to fabricate hierarchical structures not achievable by conventional methods, such as introducing condensation-induced anisotropy. ![Colloidal co-assembly 3](/sites/g/files/omnuum6296/files/styles/hwp_1_1__720x720_scale/public/aizenberg/files/coassembly.possible_04.jpg?itok=C1-8VUqZ) Direct and inverse opals can be produced in a variety of form factors. ## Publications Download 7 citations download- [BibTeX](/bibcite/export?pager_style=standard_pager&number_of_items=15&sort_field=bibcite_year--desc&taxonomy_filters%5Bfield_hwp_c_researchtopics12%5D%5B0%5D%5Btarget_id%5D=106131&taxonomy_filters%5Bfield_hwp_c_project%5D%5B0%5D%5Btarget_id%5D=111586&taxonomy_filters%5Bfield_hwp_c_project%5D%5B1%5D%5Btarget_id%5D=111661&&&format=bibtex) - [EndNote X3 XML](/bibcite/export?pager_style=standard_pager&number_of_items=15&sort_field=bibcite_year--desc&taxonomy_filters%5Bfield_hwp_c_researchtopics12%5D%5B0%5D%5Btarget_id%5D=106131&taxonomy_filters%5Bfield_hwp_c_project%5D%5B0%5D%5Btarget_id%5D=111586&taxonomy_filters%5Bfield_hwp_c_project%5D%5B1%5D%5Btarget_id%5D=111661&&&format=endnote8) - [EndNote 7 XML](/bibcite/export?pager_style=standard_pager&number_of_items=15&sort_field=bibcite_year--desc&taxonomy_filters%5Bfield_hwp_c_researchtopics12%5D%5B0%5D%5Btarget_id%5D=106131&taxonomy_filters%5Bfield_hwp_c_project%5D%5B0%5D%5Btarget_id%5D=111586&taxonomy_filters%5Bfield_hwp_c_project%5D%5B1%5D%5Btarget_id%5D=111661&&&format=endnote7) - [Endnote tagged](/bibcite/export?pager_style=standard_pager&number_of_items=15&sort_field=bibcite_year--desc&taxonomy_filters%5Bfield_hwp_c_researchtopics12%5D%5B0%5D%5Btarget_id%5D=106131&taxonomy_filters%5Bfield_hwp_c_project%5D%5B0%5D%5Btarget_id%5D=111586&taxonomy_filters%5Bfield_hwp_c_project%5D%5B1%5D%5Btarget_id%5D=111661&&&format=tagged) - [Marc](/bibcite/export?pager_style=standard_pager&number_of_items=15&sort_field=bibcite_year--desc&taxonomy_filters%5Bfield_hwp_c_researchtopics12%5D%5B0%5D%5Btarget_id%5D=106131&taxonomy_filters%5Bfield_hwp_c_project%5D%5B0%5D%5Btarget_id%5D=111586&taxonomy_filters%5Bfield_hwp_c_project%5D%5B1%5D%5Btarget_id%5D=111661&&&format=marc) - [PubMedId](/bibcite/export?pager_style=standard_pager&number_of_items=15&sort_field=bibcite_year--desc&taxonomy_filters%5Bfield_hwp_c_researchtopics12%5D%5B0%5D%5Btarget_id%5D=106131&taxonomy_filters%5Bfield_hwp_c_project%5D%5B0%5D%5Btarget_id%5D=111586&taxonomy_filters%5Bfield_hwp_c_project%5D%5B1%5D%5Btarget_id%5D=111661&&&format=pubmed_id) - [RIS](/bibcite/export?pager_style=standard_pager&number_of_items=15&sort_field=bibcite_year--desc&taxonomy_filters%5Bfield_hwp_c_researchtopics12%5D%5B0%5D%5Btarget_id%5D=106131&taxonomy_filters%5Bfield_hwp_c_project%5D%5B0%5D%5Btarget_id%5D=111586&taxonomy_filters%5Bfield_hwp_c_project%5D%5B1%5D%5Btarget_id%5D=111661&&&format=ris) ### 2025 Lim KRG, Owen CJ, Kaiser SK, Routh PK, Mendoza M, Park K-CK, Kim T-S, Garg S, Gardener JA, Russotto L, et al. [Nanoscale wetting controls reactive Pd ensembles in synthesis of dilute PdAu alloy catalysts](/publication/nanoscale-wetting-controls-reactive-pd-ensembles-synthesis-dilute-pdau-alloy-catalysts). Nature Communications. 2025;16:6293. Lim KRG, Owen CJ, Kaiser SK, Routh PK, Mendoza M, Park K-CK, Kim T-S, Garg S, Gardener JA, Russotto L, et al. [Nanoscale wetting controls reactive Pd ensembles in synthesis of dilute PdAu alloy catalysts](/publication/nanoscale-wetting-controls-reactive-pd-ensembles-synthesis-dilute-pdau-alloy-catalysts). Nature Communications. 2025;16:6293. - add\_circle\_outline do\_not\_disturb\_on Abstract - [ descriptionPublisher's Version](https://doi.org/10.1038/s41467-025-61540-4) The performance of bimetallic dilute alloy catalysts is largely determined by the size of minority metal ensembles on the nanoparticle surface. By analyzing the synthesis of catalysts comprising Pd8Au92 nanoparticles supported on silica using surface... - [ descriptionPublisher's Version](https://doi.org/10.1038/s41467-025-61540-4) ### 2020 Phillips KR, Zhang CT, Yang T, Kay T, Gao C, Brandt S, Liu L, Yang H, Li Y, Aizenberg J, et al. [Fabrication of Photonic Microbricks via Crack Engineering of Colloidal Crystals](/publications/fabrication-photonic-microbricks-crack-engineering-colloidal-crystals-0). Advanced Functional Materials. 2020;(30):1908242. doi:10.1002/adfm.201908242 Phillips KR, Zhang CT, Yang T, Kay T, Gao C, Brandt S, Liu L, Yang H, Li Y, Aizenberg J, et al. [Fabrication of Photonic Microbricks via Crack Engineering of Colloidal Crystals](/publications/fabrication-photonic-microbricks-crack-engineering-colloidal-crystals-0). Advanced Functional Materials. 2020;(30):1908242. doi:10.1002/adfm.201908242 - add\_circle\_outline do\_not\_disturb\_on Abstract Evaporation-induced self-assembly of colloidal particles is one of the most versatile fabrication routes to obtain large-area colloidal crystals; however, the formation of uncontrolled “drying cracks” due to gradual solvent evaporation represents a... ### 2015 Kaplan C, Wu N, Mandre S, Aizenberg J, Mahadevan L. [Dynamics of evaporative colloidal patterning](/publications/dynamics-evaporative-colloidal-patterning). Physics of Fluids. 2015;27(9):092105. doi:10.1063/1.4930283 Kaplan C, Wu N, Mandre S, Aizenberg J, Mahadevan L. [Dynamics of evaporative colloidal patterning](/publications/dynamics-evaporative-colloidal-patterning). Physics of Fluids. 2015;27(9):092105. doi:10.1063/1.4930283 - add\_circle\_outline do\_not\_disturb\_on Abstract - [ descriptionPublisher's Version](http://nrs.harvard.edu/urn-3:HUL.InstRepos:23670482) Drying suspensions often leave behind complex patterns of particulates, as might be seen in the coffee stains on a table. Here, we consider the dynamics of periodic band or uniform solid film formation on a vertical plate suspended partially in a drying... - [ descriptionPublisher's Version](http://nrs.harvard.edu/urn-3:HUL.InstRepos:23670482) ### 2014 Phillips K, Vogel N, Hu Y, Kolle M, Perry C, Aizenberg J. [Tunable Anisotropy in Inverse Opals and Emerging Optical Properties](/publications/tunable-anisotropy-inverse-opals-and-emerging-optical-properties). Chem. Mater. 2014;26(4):1622–1628. doi:10.1021/cm403812y Phillips K, Vogel N, Hu Y, Kolle M, Perry C, Aizenberg J. [Tunable Anisotropy in Inverse Opals and Emerging Optical Properties](/publications/tunable-anisotropy-inverse-opals-and-emerging-optical-properties). Chem. Mater. 2014;26(4):1622–1628. doi:10.1021/cm403812y - add\_circle\_outline do\_not\_disturb\_on Abstract - [ descriptionPublisher's Version](https://pubs.acs.org/doi/abs/10.1021/cm403812y) Using self-assembly, nanoscale materials can be fabricated from the bottom up. Opals and inverse opals are examples of self-assembled nanomaterials made from crystallizing colloidal particles. As self-assembly requires a high level of control, it is... - [ descriptionPublisher's Version](https://pubs.acs.org/doi/abs/10.1021/cm403812y) Phillips K, Vogel N, Burgess I, Perry C, Aizenberg J. [Directional Wetting in Anisotropic Inverse Opals](/publications/directional-wetting-anisotropic-inverse-opals). Langmuir. 2014;30(25):7615–7620. doi:10.1021/la5015253 Phillips K, Vogel N, Burgess I, Perry C, Aizenberg J. [Directional Wetting in Anisotropic Inverse Opals](/publications/directional-wetting-anisotropic-inverse-opals). Langmuir. 2014;30(25):7615–7620. doi:10.1021/la5015253 - add\_circle\_outline do\_not\_disturb\_on Abstract - [ descriptionPublisher's Version](https://pubs.acs.org/doi/abs/10.1021/la5015253) Porous materials display interesting transport phenomena due to restricted motion of fluids within the nano- to microscale voids. Here, we investigate how liquid wetting in highly ordered inverse opals is affected by anisotropy in pore geometry. We... - [ descriptionPublisher's Version](https://pubs.acs.org/doi/abs/10.1021/la5015253) ### 2012 Mishchenko L, Hatton B, Kolle M, Aizenberg J. [Patterning Hierarchy in Direct and Inverse Opal Crystals](/publications/patterning-hierarchy-direct-and-inverse-opal-crystals). Small. 2012;8(12):1904–1911. doi:10.1002/smll.201102691 Mishchenko L, Hatton B, Kolle M, Aizenberg J. [Patterning Hierarchy in Direct and Inverse Opal Crystals](/publications/patterning-hierarchy-direct-and-inverse-opal-crystals). Small. 2012;8(12):1904–1911. doi:10.1002/smll.201102691 - [ picture\_as\_pdf2012Small.Mishchenko.patt...](/sites/g/files/omnuum6296/files/2012Small.Mishchenko.patterning_hierarchy_0.pdf) - [ picture\_as\_pdf2012Small.Mishchenko.patt...](/sites/g/files/omnuum6296/files/2012Small.Mishchenko.patterning_hierarchy_0.pdf) ### 2010 Hatton B, Mishchenko L, Davis S, Sandhage KH, Aizenberg J. [Assembly of large-area, highly ordered, crack-free inverse opal films](/publications/assembly-large-area-highly-ordered-crack-free-inverse-opal-films). Proc. Nat. Acad. Sci. USA. 2010;107:10354–10359. Hatton B, Mishchenko L, Davis S, Sandhage KH, Aizenberg J. [Assembly of large-area, highly ordered, crack-free inverse opal films](/publications/assembly-large-area-highly-ordered-crack-free-inverse-opal-films). Proc. Nat. Acad. Sci. USA. 2010;107:10354–10359. - [ picture\_as\_pdf2010\_PNAS.pdf](/sites/g/files/omnuum6296/files/2010_PNAS_0.pdf) - [ picture\_as\_pdf2010\_PNAS.pdf](/sites/g/files/omnuum6296/files/2010_PNAS_0.pdf) ## Media Coverage [The dynamics of evaporative patterning](http://www.seas.harvard.edu/news/2015/10/dynamics-of-evaporative-patterning), Harvard press release, October 6, 2015. [Controlling Evaporative Patterning Transitions](https://www.aip.org/publishing/journal-highlights/controlling-evaporative-patterning-transitions), American Institute of Physics, September 29, 2015.