An Emerging Pore‐Making Strategy: Confined Swelling‐Induced Pore Generation in Block Copolymer Materials

Wang, Yong; Li, Fengbin

doi:10.1002/adma.201004022

Cited by 157 publications

(158 citation statements)

References 100 publications

Supporting

Mentioning

158

Contrasting

Order By: Relevance

“…We broke through this limitation by elevating the swelling temperatures to be comparable to the glass transition temperature (T g ) of the majority blocks in the swelling agent, and established a new pore-making strategy of selective swelling-induced pore generation that is capable of creating pores in BCPs with any dimension including bulk materials in macroscopic dimensions. 11,12 Starting in 2010, we have focused on swelling-induced pore generation in bulk BCP materials because they are expected to find many important applications beyond lithography, which is currently the main target application of ultrathin BCP films. 18 This Account will summarize and analyze our new insights and discoveries of this burgeoning pore-making method with an emphasis on the development of ordered porosities in bulk BCP materials, mainly focused on the morphology evolution, mechanistic understanding, pore tuning, and applications of the produced porous bulk materials.…”

Section: Introductionmentioning

confidence: 99%

Nondestructive Creation of Ordered Nanopores by Selective Swelling of Block Copolymers: Toward Homoporous Membranes

Wang

2016

Acc. Chem. Res.

Self Cite

108

View full text Add to dashboard Cite

Pores regulate the entry and exit of substances based on the differences in physical sizes or chemical affinities. Pore uniformity, ordering, and the homogeneity of the surface chemistry of the pore walls are vital for maximizing the performance of a porous material because any scattering in these parameters weakens the capability of pores to discriminate foreign substances. Most strategies for the creation of homogeneous pores are destructive, and sacrificial components in the precursor materials must be selectively removed to generate porosities. The incorporation and subsequent removal of the sacrificial components frequently make the pore-making process complicated and inefficient and impose greater uncertainty in the control of the pore homogeneity. Block copolymers (BCPs) have been demonstrated to be promising precursors in the fabrication of highly ordered nanoporous structures. Unfortunately, BCP-derived porosities are also predominantly dependent on destructive pore-making processes (e.g., etching or extraction). To address this problem, we have developed a swelling-based nondestructive strategy. In this swelling process, one simply needs to immerse BCP materials in a solvent selective for the minority blocks for hours. After removing the BCPs from the solvent followed by air drying, pores are generated throughout the BCP materials in the positions where the minority blocks initially dwell. This Account discusses our recent discoveries, new insights, and emerging applications of this burgeoning pore-making method with a focus on the development of ordered porosities in bulk BCP materials. The initial morphology and orientation of the minority phases in BCPs determine the pore orientation and geometry in the produced porous materials. For nonaligned BCPs, three-dimensionally interconnected pores with sizes scattering in the 10-50 nm range are produced after swelling. There is a morphology evolution of BCP materials from the initial nonporous structure to the increasingly opened nanoporous intermediates, to interconnected networks of micellar nanofibers, and finally to isolated micellar spheres with increasing degrees of swelling. When the BCP films are aligned perpendicularly or in-plane, selective swelling results in uniform "standing" (perpendicular orientation) and "sleeping" (in-plane orientation) pores, respectively. Pore sizes can be tuned by changing molecular weights of the BCPs and swelling conditions without the loss of pore uniformity. Due to the nondestructive nature of this swelling process, nothing in the BCPs is lost during the pore-forming procedure, and consequently the formed pores can be progressively closed also by selective swelling. Such reversible pore opening/closing can be repeated many times, enabling the application of these materials in drug delivery and intelligent antireflective coatings. The monodispersed pore sizes, straight pore profile, and hydrophilic pore walls particularly favor the application of the porous BCPs in separations as homoporous membranes (HOMEs) exhibitin...

show abstract

Section: Introductionmentioning

confidence: 99%

Nondestructive Creation of Ordered Nanopores by Selective Swelling of Block Copolymers: Toward Homoporous Membranes

Wang

2016

Acc. Chem. Res.

Self Cite

108

View full text Add to dashboard Cite

show abstract

“…[14,55] Subsequently, cylindrical cavities are formed 1) by the selective degradation of the cylindrical microdomains through a chemical or photochemical reaction, [15] or 2) by the extraction/evaporation of small molecules or short homopolymers confined within the cylindrical domains. [16] The former strategy was first demonstrated on polyA C H T U N G T R E N N U N G (isoprene)-based microdomains that were degraded by ozonolysis, [56] and have been widely used to fabricate polystyrene-based nanoporous monoliths from PS-b-PLA (through the hydrolysis of the PLA domains) [57] and from PS-b-PMMA (through the UV-induced photodegradation of the PMMA domains). [58] The latter takes advantages of the selective incorporation of small template molecules, homopolymers, or solvents into cylindrical microdomains formed from BCPs, in particular, amphiphilic BCPs such as PS-b-P4VP.…”

Section: Bcp-derived Nanoporous Monoliths For Analytical Applicationsmentioning

confidence: 99%

“…[5,[15][16][17] The resulting well-ordered nanopores can serve as templates to fabricate nanodot/nanorod arrays, [5,6] as nanoscale cham- bers for crystal preparation, [18] and as chemical separation media for solution samples. [10,19] In chemical/biological sensing and separations, nanoporous media, such as three-dimensionally entangled polymers, have been widely used owing to their unique permeability, which reflects steric and electrostatic interactions within the nanoscale cavities.…”

Section: Introductionmentioning

confidence: 99%

Block Copolymer‐Derived Monolithic Polymer Films and Membranes Comprising Self‐Organized Cylindrical Nanopores for Chemical Sensing and Separations

Ito

2014

Chemistry An Asian Journal

View full text Add to dashboard Cite

Microphase separation of block copolymers (BCPs) has been extensively studied because it leads to the self-assembled formation of periodic structures controlled on the scale of tens of nanometers. In particular, BCP-derived cylindrical microdomains have attracted considerable interest for various applications owing to their well-defined shapes of uniform and tunable diameters. This focus review highlights recent efforts to apply BCP-derived monolithic films/membranes comprising cylindrical nanopores for chemical sensing and separations. The nanopores provide confined molecular pathways that exhibit enhanced selectivity based on steric, electrostatic, and chemical interactions, and thus, enable us to design unique electrochemical sensors and highly efficient separation membranes.

show abstract

“…[1][2][3] properties. [ 25,26 ] Ferritin (Horse spleen ferritin, HSF) is an iron storage protein in mammals and consists of a dodecameric protein cage of 12 nm in diameter with a 6 nm central cavity containing a phosphate ferrihydrite core.…”

Section: Introductionmentioning

confidence: 97%

Ultra‐Thin Self‐Assembled Protein‐Polymer Membranes: A New Pore Forming Strategy

Rijn

Tutuş

Kathrein

et al. 2014

Adv Funct Materials

View full text Add to dashboard Cite

Self‐assembled membranes offer a promising alternative for conventional membrane fabrication, especially in the field of ultrafiltration. Here, a new pore‐making strategy is introduced involving stimuli responsive protein‐polymer conjugates self‐assembled across a large surface area using drying‐mediated interfacial self‐assembly. The membrane is flexible and assembled on porous supports. The protein used is the cage protein ferritin and resides within the polymer matrix. Upon denaturation of ferritin, a pore is formed which intrinsically is determined by the size of the protein and how it resides in the matrix. Due to the self‐assembly at interfaces, the membrane constitutes of only one layer resulting in a membrane thickness of 7 nm on average in the dry state. The membrane is stable up to at least 50 mbar transmembrane pressure, operating at a flux of about 21 000–25 000 L m−2 h−1 bar−1 and displayed a preferred size selectivity of particles below 20 nm. This approach diversifies membrane technology generating a platform for “smart” self‐assembled membranes.

show abstract

An Emerging Pore‐Making Strategy: Confined Swelling‐Induced Pore Generation in Block Copolymer Materials

Cited by 157 publications

References 100 publications

Nondestructive Creation of Ordered Nanopores by Selective Swelling of Block Copolymers: Toward Homoporous Membranes

Nondestructive Creation of Ordered Nanopores by Selective Swelling of Block Copolymers: Toward Homoporous Membranes

Block Copolymer‐Derived Monolithic Polymer Films and Membranes Comprising Self‐Organized Cylindrical Nanopores for Chemical Sensing and Separations

Ultra‐Thin Self‐Assembled Protein‐Polymer Membranes: A New Pore Forming Strategy

Contact Info

Product

Resources

About