TEMPLATED SYNTHESIS OF NANOVOIDED POLYMERS
A method of forming a voided polymer includes forming a polymerizable composition containing a polymer precursor and a solid templating agent, forming a coating of the polymerizable composition, processing the coating to form a cured polymer material having a solid phase in a plurality of defined regions, and removing at least a portion of the solid phase from the cured polymer material to form a voided polymer layer.
1 . A method comprising:
forming a polymerizable composition comprising a polymer precursor and a solid templating agent;
forming a coating of the polymerizable composition;
processing the coating to form a cured polymer material comprising a solid phase in a plurality of defined regions; and
removing at least a portion of the solid phase from the cured polymer material to form a voided polymer layer.
2 . The method of claim 1 , further comprising processing the polymerizable composition to form a homogeneous solution.
3 . The method of claim 1 , wherein removing at least a portion of the solid phase comprises subliming the templating agent at a temperature between approximately 30° C. and approximately 300° C.
4 . The method of claim 1 , wherein the templating agent comprises a polyaromatic hydrocarbon.
5 . The method of claim 1 , wherein the templating agent is selected from the group consisting of 2-naphthol, anthracene, benzoic acid, salicylic acid, camphor, saccharin, quinine, cholesterol, palmitic acid, stearic acid, acetylsalicylic acid, atropine, arsenic, piperazine, and 1,4-dichlorobenzene.
6 . The method of claim 1 , wherein the plurality of defined regions comprise templating material-rich domains having a maximum dimension of less than approximately 20 μm.
7 . The method of claim 1 , wherein removing at least a portion of the solid phase comprises sublimation.
8 . The method of claim 1 , wherein the voided polymer layer has an elastic modulus of from approximately 0.2 MPa to approximately 500 MPa.
9 . The method of claim 1 , wherein the polymerizable composition further comprises an initiator selected from the group consisting of a UV radical initiator, a thermal radical initiator, and a redox radical initiator.
10 . A method comprising:
forming a homogeneous solution comprising a polymer precursor and a solid templating agent;
forming a layer of the solution on a substrate;
processing the layer to form a cured polymer material comprising discrete domains of a solid templating agent phase; and
removing at least a portion of the solid phase from the domains to form a voided polymer layer.
11 . The method of claim 10 , wherein the templating agent comprises a polyaromatic hydrocarbon.
12 . The method of claim 10 , wherein the templating agent is selected from the group consisting of 2-naphthol, anthracene, benzoic acid, salicylic acid, camphor, saccharin, quinine, cholesterol, palmitic acid, stearic acid, acetylsalicylic acid, atropine, arsenic, piperazine, and 1,4-dichlorobenzene.
13 . The method of claim 10 , wherein removing at least a portion of the solid phase comprises sublimation.
14 . A voided polymer comprising:
a polymer matrix having a plurality of voids non-homogeneously dispersed throughout the polymer matrix.
15 . The voided polymer of claim 14 , wherein the voids exhibit a dendritic pattern.
16 . An actuator element comprising a layer of the voided polymer of claim 14 , wherein the voided polymer layer is disposed between conductive electrodes.
17 . An acoustic element comprising the voided polymer of claim 14 .
18 . A method comprising:
introducing a vaporized reactant composition into a reaction chamber, the vaporized reactant composition comprising a polymer precursor and an organic templating agent;
forming a coating comprising the reactant composition over a substrate located within the reaction chamber; and
processing the coating to cure the polymer precursor and crystallize the organic templating agent to form a composite layer.
19 . The method of claim 18 , further comprising removing at least a portion of the crystallized organic templating agent from the coating to form a voided polymer layer.
20 . The method of claim 18 , further comprising forming a polymer layer over a surface of the composite layer.
21 . The method of claim 18 , further comprising pretreating substrate to locally promote crystallization of the organic templating agent.
22 . The method of claim 18 , further comprising forming a photoalignment layer over the substrate prior to forming the coating.
23 . A composite structure comprising:
organic crystalline domains dispersed among polymer domains.
24 . The composite structure of claim 23 , wherein the crystalline domains are characterized by a preferred crystallographic orientation.
25 . The composite structure of claim 23 , wherein the polymer domains are characterized by a glassy state.
26 . The composite structure of claim 23 , wherein the polymer domains are mechanically elastic.